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                Coastal Zone                                                                 90-L -2 7 1970
                 Information
                   Center                     U.S. DEPARTMENT OF COMMERCE
                                   National Oceanic and Atmospheric Administration

                                                         PRELIMINARY

                          REVISED STANDARD PROJECT HURRICANE   CRITERIA FOR THE ATLANTIC AND GULF

                                                COASTS   OFTHE UNITED STATES

                                                    MEMORANDUM HUR 7-120

                                                        Prepared by
                                                14ydrome'teorol6gical granch
                                                   ..Office of Hydrology

                                                   r

            <3                                    National Weather Service
                     QC                               Silver Spring, Md.
                     944
                     N38'                                  IJune 1972
                     1972

                          Th is draft report gives some revisions to a study covering
                        the same subject published in 1958 [1]. In the last two years
                        effort has been directed towa rd providing more regional details
                        in the analysis of the generalized meteorological parameters
                        used to describehurricanes. Results of that study, to be
                        completed in 1974, may-necessitate changes in standard project
                        hurricane (SPH) criteria. Another draft study [31, giving
                        similar meteorological criteria for probable maximum hurricane
                        (PMH) wind fields, will also be effected. Studies now in
                        progress are reevaluating these criteria with plans for a
                        published report sometime in 1975. This report, based on
                        ,these more detailed studies, will provide consistent SPH and-
                        PMH wind fields.

                                                        CONTENTS

                    1. Introduction   .......................................................     I

                    II. Interpretation of the SPH    ..........................................   3

                    III. SPH parameters   ...................................................     4

                    IV. Revisions to NHRP Report no. 33   .....* ..............................   5

                    V. Other SPH criteria, not revised   ....................................     10

                    VI. Isovel wind field construction   ....................................     10

                    References  ..............................................................

                    Tables

                    Figures

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                                                      PRELIMINARY

                                                 MEMORANDUM HUR 7-120

                      REVISED STANDARD PROJECT HURRICANE CRITERIA FOR THE  ATLANTIC AND GULF COASTS

                                                OF THE UNITED STATES

                                              Hydrometeorological Branch
                                                  Office of Hydrology
                                            NOAA, National Weather Service

                      I. Introduction

                           This memorandum covers revisions to Standard Project Hurricane (SPH)

                      criteria given in National Hurricane Research Project Report No. 33 [1]. The

                      need for these revisions was prompted by a comparison of the wind fields in

                      well-developed hurricanes that occurred since 1956 with those used to develop

                      the SPH in the original study. It is Believed the wind fields or average

                      radial storm winds of NHRP No. 33 Should be stronger relative to the highest

                      winds near the center of the storm. This is supported by the number of storms

                      in recent years with winds that exceed those of NHRP No.  33.Figure  1 shows

                      a comparison of the earlier radial wind profiles used in  NHRP No. 33 with the

                      profiles estimated in the more recent storms that bears outthis contention.

                      In this figure both velocity and distance are drawn on a relative basis, i.e.,

                      by ratios of actual wind to maximum wind and ratios of distance from the storm
                      center to radius of maximum wind.

                           Memorandum HUR 7-84 [2] and several subsequent memoranda of that series

                      provide revisions to NHRP No. 33 in zones B and C of the Gulf coast in order

                      to better reflect the greater windspeeds of Hurricane Carla (1961) and others.

                      Revisions of the present study are consistent with the revised values in zones
                                                                           B and C.

                   While the revision of the relative wind fields provide the main motiva-

              tion for this work, other hurricane parameters were also updated, the most

              important being the Central Pressure Index (CPI). An important consideration

              in these revisions was to maintain consistency from zone to zone with a

              study giving meteorological characteristics of the probable maximum hurricane

              [3]. Criteria for the probable maximum hurricane (PMH) are the same meteoro-

              logical parameters, some with the same values and similar developmental techni-

              ques,as those of the SPH criteria.

                   One reason why meteorological parameters, such as the CPI, need revision

              is that in the earlierstorms the lowest pressure was seldom measured and

              therefore had to be estimated by indirect methods (4]. Exceptions were those

              storms where the center passed over a land station or a ship at sea. In

              recent storms  much more reliable central pressures are often obtained through

              dropsondes from airplanes into the hurricane center.

                   The period of record for the revised SPH criteria includes all-relevant

              storms in the 72-year period from 1900 through 1971.

                   Figure 2 shows revised values for maximum winds in the SPH along the

              Atlantic coast, wi.th moderate forward speeds and mean, radii of maximum

              winds, compared to the values previously published in NHRP No. 33. The

              increased winds up to about 35*N latitude are mainly due to lower CPI

              values in the revised analyses. The slightly lower winds farther

              north are due mainly to the adoption of a peripheral pressure that varies

              with latitude.

                   The present study is meant to be an interim report, giving the major

              changes in SPH criteria from that in NHRP No. 33. Many references are

                                                   2

                     made to that report. The planned publication of revised SPH criteria will
                     contain the necessary information so that these,references need not be made.
                     II. Interpretation of the SPH
                          The SPH is a hypothetical hurricane that is  intended to represent the
                     most severe combination of hurricane parameters that is "reasonably
                     characteristid'of a specified geographic,region, excluding extremely rare
                     combinations. The SPH is intended as a practicable expression.of the maximum
                     degree of protection that should be sought as a general rule in the planning
                     and design of coastal structures for communities where  protection of human
                     life and destruction of property is involved. The height of the storm-
                     generated surge-is the critical factor. This is mainly dependent on the
                     speed and direction of winds as a hurricane nears and enters the coast.
                     Thus, the important product of the study is the hurricane  wind field.
                          There have been-liumerous inquiries indicating there are some misunder-
                     standings concerning what the SPH criteria represent. NHRP No. 33 and the
                     present revision show frequency analyses of the CPI for large zones along
                     the gulf and Atlantic coasts   The SPH uses the arbitrary 100-year return
                     period of the CPI as a standard for comparison and consistency from zone
                     to zone. However, use of 100-year return-period CPI values does not.imply,
                     that the SPH has a 100-year return period for any place in a given zone,
                     since other meteorological parameters are also important.   Hence, the
                     standard project hurricane has no,frequency assigned to it. The angle
                     of storm approach to the coastline., the rate of travel, and.the radius
                     of maximum wind are important meteorological considerations for determining
                     the hurricane surge.
                          Although a CPI with a 100-year return period may be read  from figures
                     in this report for any point along the coast, it does not. mean the  value
                     is expect ed to occur once in 100 years at that point. Because  of the manner

                                                          3

              in which the statistics of the CPI were developed (see pp. 3 and 4 in

              NHRP No. 33) the 100-year CPI at any point on the Atlantic coast, say  x,

              must be interpreted as the CPI value which may be expected to occur once in

              100 years, on the average, at some point in a 300 n. mi. zone centered at x.

              The smooth 100-year line which interpolates the CPI value from the mid-point

              of one zone to another is a convenience which insures a smooth regional pro-

              gression of the CPI values.

                   Wind fields determined from NHRP No. 33 and this revision, represent

              10-minute average speeds, standardized to a height of 30 feetabove the

              surface. The 10-minute average was adopted as a standard sustained wind.

              Storm surges cannot be generated from wind gusts. The 30-ft height above the

              surface is used to standardize observations from instruments at differing

              heights.

              III. SPH parameters

                   The independent parameters used to develop the SPH criteria are:

                   1. Central Pressure Index (CPI). This is the lowest pressure at the

                   storm center. It is an independent variable for determination of the
                   maximum gradient windspeed (V gx).
                   2. Peripheral Pressure (p n). This  is the sea-level pressure at the

                   outer limits of the hurricane wind circulation. It should not be

                   confused with the assymptotic pressure discussed in [3]. Revised
                   maximum wind (Vx) values for this report (see Part IV, F) where p ndepends
                   on latitude are shown in figure 2.

                   3. Radius of maximum wind (R). This is the radial distance from the

                   hurricane center to the location of highest winds which usually occurs

                   just outward the hurricane eye-wall cloud.
                                                   4

                      4. Forward speed (T). This is the rate of translation of the

                 hurricane center from one geographical point.to another.

                 IV.. Aevisions to NHRP Report No.33

                      .A. Added storm data

                          Table A lists hurricanes with central pressures of less than 29.00 inches

                     within each coastal zone for the 72-ydar period of record..(1900-1971). There

                     are 32 more storms than shown for a similar list in NHRP No. 33.

                          Table B lists all tropical storms which reached hurricane intensity

                      at some time and moved through one or more of the zones during the 72-4year

                      petiod of record (1900-1971). There is an increase of 50 in the number of

                      storms over those in NHRP No. 33.

                      B. Central Pressure Index (CPI) frequency analyses

                          New frequency analyses, figures 3-9., were made for each zone using
                      central pressures (p0) from table A. Changes in zone B were dictated pri-
                      mar.ily by Hurricane,Camill.e.(1969,).

                      C. Coastal profile of CPI.

                          The variation of CPI along the coast was,-obtained by fitting smooth

                      curves to the frequency analyses of the CPI values platted at the coastal

                      center of each zone. Analysis of thediscrete 100-year return-period CPI

                      values.resulted in smooth profiles along the Atlantic toast, figure 10,

                      and Gulf coast, figure 11, and gravides the necessary continuity and con-

                      sistency between the Atlantic and Gulf coasts.

                      D. Nomogram for wind field profiles

                          The generalized SPH wind field is paracentric. However, since it is

                      symmetrical, a radial wind profile taken along the line of maximum wind

                      (line M) may be used to reconstruct the entire wind field. This is done

                      by rotating the profile about the storm center, adjusting the windspeed

                      according to a simple cosine function.

                      A wind profile nomogram, figure 12, was developed from hurricane wind

                patterns observed along the Atlantic and Gulf coasts through 1971. From the

                nomogram the radial wind profile for a given radius of maximum wind is defined

                by relative wind values read from isolines of radial distance (r.in n. mi.) from
                the storm center. The relative wind (V/V     x  is the ratio of the wind (V) at a
                radial distance W to the maximum wind (V         along that radius. Profiles
                                                              x

                are defined for all radii of maximum wind from 4 to 50 n. mi. This covers

                the SPH range from small (RS) to large (RL) radius.
                      Relative wind (V/V X) profiles of some storms exceed those of the nomogram
                (see  fig. 1). The percent of storms undercut is uncertain, but it is probably

                in the range of 10-15 percent. For instance in the period 1957 through 1971,

                4 or 5 out of 32 hurricanes in the Gulf and Atlantic coastal,areas had some

                portion of their relative wind profile undercut. The storms that were

                partially undercut are: Carla (1961); Donna (1960); Ione (1955); Hazel

                (1954); Gracie (1959); and Camille (1969). This, however, does not mean that
                the actual SPH winds undercut all of these storms since the maximum wind (V       x

                must also be considered.

                                                        6

                        Profiles from the nomogram, figure 12, provide higher windspeeds

                   relative to the maximum wind (V    than did NHRP No. 33 over the entire wind

                   field in all zones. This is shown in figure 13, for zone C where the avewage

                   increase along the profile is about 10 percent. The figure also shows profiles

                   used in two earlier SPH wind field revisions (2, 51. The increase over NHRP

                   No. 33 for other zones ranges to about 20 percent for mean (RM) and large

                   (RL) radii of maximum winds.
                        E. Maximum gradient windspeed (V  gx
                            The maximum gradient windspeed equation
                                              V gx . K'Vpn@ po -R (0.575T)
                        from [4), provides a means for computing the maxi-im windspeed in a
                        SPH whose other parameters are known. V  gx is in mph when P n and p0 are in
                        inches, R is in n. mi. and f is in hr-1.   The coefficient (kyvaries with

                        latitude [3] in the revised SPH criteria as opposed to a constant value of

                        73.0 used in NHRP No. 33. The peripheral pressure (p      also varies with
                        latitude. Figure 14 shows a plot of p  n versus latitude in storms and the

                        adopted curve.

                            The central pressure (p 0), the radius of maximum wind (R), and storm
                       speed (T) .are given In table 1. The values of V gx for mean (RM) and large
                       (RL) radius of maximum wind were computed and also appear in table 1, after

                       conversion to knots.

                        F. Maximum windspeed (V  x
                            The maX4-um windspeed, in knots, adjusted to 30 feet above the water

                        surface is defined by the equation:

                                             V - 0.865 V    + 0.5T                          (2)
                                              x          gx

                                                       7

                      where the gradient windspeed, V  gX , from equation (1) is in knots and
                      the forward speed, T, is in knots. V   x was evaluated at 48 discrete

                      geographical locations on the Atlantic and Gulf coasts using the two

                      values of V    (for RM and RL) for slow (ST), moderate (MT), and fast
                                  gx
                      (HT) forward speeds. These values are listed in table 1. The same

                      overwater friction coefficient, 0.865, for reducing the gradient wind

                      to 30 feet above the.surface, was used in all zones.

                      G. Wind fields

                          Construction of isovel patterns involves rotation of the radial pro-

                      file of windspeed about the hurricane center. If this is done by hand

                      computation techniques, it is necessary to first sketch the wind profile

                      along the radius of maximum wind, using figure 12. Under normal cir-

                      cum tances this radius, or line of maximum winds, extends to the right

                      of the direction of motion vector of the storm, making an angle of 115*

                     with the direction vector. To get the windspeed, V... at any point
                     x, a distance r from the center of the SPH, and that does not lie on line

                     M, the expression

                                                     V     V       (1-cose)                 (3)
                                                      XP    x    2

                      is used.    x is the windspeed along the-profile on   M at a distancer

                      from the  center and 6 is the angle between line M and radius vector

                      through x.

                          Although an angle of 115* between line M and the direction of storm

                      motion is preferred, this angle may be any value from 15* to 165*. This

                      agrees with the limits of rotation given in NHRP No. 33.

                                                       8

                           The wind direction is defined as the angle of incurvature over the
                        wind field. The angle of incurvature is the angle between the wind
                        direction and a tangent to a circle centered over the storm, and is
                        consider ed to be positive when the wind has a component directed toward
                        the storm center. The angle of incurvature criteria, the same as that

                        shown in NHRP No. 33, is as follows.

                                       Radius                Angle of incurvature
                           1. Center out to region of              00-100

                               maximum winds (R)

                           2.  R out to 1.2 R,                    100-250

                           3.  1.2 R and outward                    250

                        Radial wind profiles for each zone from this study are compared with

                        those in NHRP No. 33, in figures 15 through 21. The profile for zone C,

                        figure 21, was used to construct a sample'wind field, figure 22. This

                        is for mile 360 with a moderate forward speed and mean radius.

                        H. Radius Of maximum winds (R)-and forward speed (T)
                           Some of the values of the CPI (p .) were revised, and since R is some-
                        what dependent on p0 (see figure 7 and 17, NHRP No.'33) the values of the
                        three categories oi.R (small,'mean, and large)were accordingly revised.

                        The new values in table 11&re only slightly different from'those in table 1

                        of NHRP No. 33.

                           The values of the three categories 6f the forward speed (slow, moderate,

                        and fast), read from figures 9 and 20, NHRP No. 33, resulted in slight

                        differences from those originally published in table 1.

                                                      9

                   I. Frictional adjustment for windspeeds over land

                       In NHRP No. 33, a constant factor of 0.70 was used for reducing

                   over-water winds to over-land. For the present revision,,,we recommend a

                   variation in this reduction factor with the windspeed. The basis for

                   this is shown in figure 30 of HMR #32 [4]. For windspeeds less than

                   10 knots, use 0.40, for speeds greater than 73 knots use 0.78. In-

                   terpolate linearly for intermediate speeds. These reduction factors

                   for any over-water speed represent lower limiting values for the over-

                   land windspeed at a point which is at least 10 miles inland along a

                   trajectory starting at the coast. In other words, the reduction

                   should be accomplished in about 10 miles over land. The speed-up when

                   the trajectory leaves land to go back over water also occurs in about

                   10 miles.

              V.* Other SPH crtteria, not revised

                   Other criteria for the SPH, such as adjustment for filling over land,

              and adjustment of windspeeds near shore, have not undergone revision.

              VIo Isovel wind field construction

                   The procedure for constructing a revised SPH,wind field is illustrated

              by the following example for a location,along the Atlantic coast at 25.5*N.

              latitude. This example uses a mean radius of maximum wind (RM) and a moderate

              forward speed (MT).

                   1. From table 1, mean radius of maximum wind, (RM),,for the location
              is 8 n. mi., maximum windspeed (Vx) is 109 knots, and moderate forward speed

              (MT) is 10 knots.

                                                  10

                         2. Using figure 12, read off relative windspeeds (V/Vx) at various
                   distances from the center for RM of 8 n. mi. For this example, the
                   following table gives the V/V    x and the actual wind, V, at the given     Idistances.

                              Distance from                V/V x            V (kts)
                             center (n. mi.)

                                      8                   1.000              109

                                      9                    .995              108

                                    12                     .970              106

                                    16                    -916               100

                                    20                     .823                90

                                    30                     .698                76

                                    40                     .619                67

                                    50                     .559                61

                                    60                     0506                55

                                   @80                     .431'               47

                                   100                     .368                40

                                   120                     .317                35

                                   150                     .244                27

                                   200                     .158                17

                         3. For the   values of V inside    RM, read off relative'distances from

                   the center and relative windspeeds from      figure 23. Construct table, as in

                   step 2.

                   Relative distance        Relative        V    V/V x 109      r = r/R x 8
                   from center (r/R)      speed (V/V                 x
                                                     x           (knots)           (n. mi.)

                           .2                  .025                  3               1.6

                           .4                  .117                13                3.2

                           .5                  .227                25                4.0

                           .6                  .450                49                4.8

                           .7                  .735                80                5.6

                           .75                 .835                91                6.0

                           .8                  .900                98                6.4

                           .9                  .970                106               7.2

                      4.   Plot the values of steps 2 and 3, (V versus distance from centert
                 r,) on graph paper, as in figures 24     1, upper right, and upper left. This

                 ,gives the windspeed values for any point along the line of maximum winds.

                      5. On a large sheet (2'x2'), lay off a line (M), scaled with distance

                 from a point designated as the center of the SPH. On this line, plot winds

                 computed in steps 2 and 3 or interpolated from step 4*(See figure 24.)
                      6. To compute the windspeed V      XP , at any point x in the SPH wind field
                 that does not lie on line M, use the following equation:

                                                  VxP = V-T/2 (1-cosB),

                 where V is the windspeed along line M at the distance r from the center.

                      To show, in general,'how the equation is used consider the point, X,

                 50 n. mi. from the storm center making an angle e of 60* with line M.

                  The plot, figure 24, should be on a reasonably large graph paper in order
                  to obtain deatils on winds within RM. We suggest a sheet about 2'2'.

                                                         12

                          a. On figure 24 read V, Atong line M, of 61 knots at a distance of

                              50 n. mi. from the center.

                          b. Substituting in the equation gives

                                                          10
                                                V     61-  2 (1-.5)   58.5 knots

                          7.  To determine a particular isovel, say for 40 knots, the, following

                              is suggested.

                          a.  Mark the 40-knot point on line M, using figure 24, upper right,

                              to get distance from the center.

                          b.  Using the nomogram, figure 25, sketch in selected radial lines

                              that indicate factors applied to forward speed (T) to find the

                              40-knot value at other points. These are tick marks .1,..2, etc.,

                              on figure 24, lower portion. Note that the 1.0 mark is.diametrically

                              opposite to line M.

                          c.  To get the distance of the 40-knot valu6,from the center.,along the

                              radial tick mark OA, multiply 10 (the value-of T) by OA to get,

                              4. Add 4 to 40 to get 44.

                          d.  From upper right profile of figure 24, find the,distance from center

                              (along M), of the 44 knots and plot along line marked 0.4., This

                              gives the location of the 40-knot wind on radial 0.4. Make similar

                              computations for other radials to provide a smooth isovel around full

                              circle of the pattern. Since the wind field is symmetrical about

                              line M, half the pattern may be folded over to obtain the complete

                              wind field.

                                                       13

                     e. For determining other isovels outside of R, follow the same

                         procedure.

                     f. For isovels inside of R, use the same procedure, utilizing

                     the wind profile in the upper left corner of figure 24.

                     A little experimenting will make the following evident. All isovels

                that have values larger than the differences between the maximum wind and the

                forward speed of the storm will be crescent or kidney-shaped. For the

                particular example above, where V - 109 and T = 10, all isovels with values
                                                  x

                between 99 and 109 are crescent-ahaped. See example of the 100-knot isovel

                in figure 24. All other isovels are more or less circular.

                Alternate to detailed approach. Without sacrificing much accuracy, all nearly
                circular isovels may be drawn as true circles, provided the forward speed, T,

                is relatively low, say, 12 knots or less. To do this for the 40-knot isovel

                as an example, perform step 7a above. To find the 40-knot point on the ex-

                tension of M on the opposite side of the center use figure 24 again and find

                the distance from center to the 50 knot (40 + T = 50) value. Find the mid-

                point, on line M of the two points above, and using this as a center, draw

                a circle through the two points. This is the 40-knot isovel. Other isovels

                are determined in a similar manner.

                                                    14

                                                    REFERENCES

                    1.   U. S. Weather Bureau,."Meteorological Considerations Pertinent to

                         Standard Project Hurricane, Atlantic and Gulf Coasts of the United

                         States," National Hurricane Research Project Report No. 33, 1958.

                    2.   Memorandum HUR 7-84, Standard Project Hurricane Wind Field Patterns

                         (revised) to replace existing patterns in NHRP Report No. 33,.for

                         Zones B & C, August 17, 1965.

                    3.   Memoranda HUR 7-97 and HUR 7-97A, "Interim Report - Meteorological

                         Characteristics of the Probable Maximum Hurricane, Atlantic and Gulf

                         Coasts of the United States," May 7, 1968, along with "Peripheral

                         Pressures for Probable Maximum Hurricanes," December 3, 1968.

                    4.   U. S. Weather Bureau, "Characteristics:of United States,Hurricanes'

                         Pertinent to Levee Design for Lake Okeechobee, Florida," Hydrometeoro-

                         logical Report No. 32, 1954.

                    5.   MEMORANDUM HUR 7-94, Surface Winds (30 ft.).in Standard Project

                         Hurricane Critical to Espiritu Santo Bay (Matagorda Bay, Texas), for

                         Large Radius of Maximum Winds and For Fast, Moderate and Slow Forward

                         Speed.

                                                        15

                                                           Table 1.--Standard project hurricane index characteristics

                        Coastal Location             CPI            Radius of Max. Wind       Forward Speed (T)                   Renregentative Maximum Wind Speeds (Knots)
                      Zone      Lat. (ON.)     (inches    (ab)         (Nautical  Miles)           (Knots)            Mean Radius of Max. Wind                  Large Radius of Max. Wind
                                                                         RS   RM    Rt        ST      MT       HT    V (RM) V (ST) V (14T) V (HT)              V (RL) V,(ST) V (MT) V (HT)
                                                                                                                        9z       x        x         x            gx       x        x       X

                                   23           26.56     899.1           4    7    11          4     10       16       123      .109     112       115           123     108      111     114
                                   24           26.61     901.1           4    8    11          4     10       16       122      108      ill       114           122     108      ill     114
                                   25           26.68     903.5           4    8    12          4     10       16       121      107      110       113           121     106      109     112
                                   25.5         26.73     905.2           4    8    13          4     10       17       120      106      109       112           119     105      108     112
                                   26           26.77     906.5           4    9    14          4     11       17       119      105      109       112           119     105      108     ill
                                   27           26.88     914.0           5   10    17          4     11       18       117      103      107       110           116     102      106     109

                        2

                                   28           27.02     915.0           5   12    21          4     11       19       114      101      104       108           113     100      103     107
                                   29           27.21     921.4           6   14    27          4     11       20       110       97      101       105           108      96      99      104
                                   30           27.38     927.2           7   16    31          4     11       21       105       93        97      102           103      91      95      100
                                   30.5         27.43     928.9           7   16    32          4     11       22       104       92        95      101           l0i      90      94        99
                                   31           27.46     929.9           7   17    34          4     11       23       103       91        95      101           101      89      93        99
                                   32           27.49     930.9           7   16    32          4     12       26       102       90        94      101            99      88      9i        99

                        3

                                   33           27.48     930.6           7   16    31          4     13       30       100       89        93      102            98      87      92      100
                                   34           27.46     929.9           6   15    30          5     15       34       100       89        94      103            97      87      92      101
                                   35           27.44     929.2           6   15    29          5     17       39        98       88        94      105            96      86      92      103
                                   35.5         27.44     929.2           6   15    29          5     18       41        98       87        93      105            .95     85      92      103
                                   36           27.45     929.6           6   15    29          6     20       42        96       87        94      105            94      85      92'     103
                                   37           27.49     930.9           7   16    31          8     23       45        94       85        93      104            91      83      91      102

                       4

                                   38           27.55     933.0           7   17    34        10      26       47        90       83        91      102            88      81      89        99
                                   39           27.63     935.7           7   18    38        12      29       49        87       81        90      100            84      78      87        97
                                   40           27.72     938.7           8   19    43        14      32       51        83       79        88       98            79      76      85
                                   40.5         27.77     940.4           8   20    46        15      34       51        81       78        87       96            77      74      83        92
                                   41           27.82     942.1           8   21    50        16      35       52        79       76        86       94            74      72      82        90
                                   42           27.92     945.5           9   23    56        17      36       53        75       73        83       91            69      68      78        86
                                   43           28.03     949.2           9   26    64        17      37       53        71       70        80       88            64      64      74        82
                                   44           28.15     953.3          10   28    72        17      38       153       67       66        77       84            59      59      70        77
                                   45           28.26     956.7          11   31    80        17      39       53        63       63        74       81            53      55      66        73.

                                                                                                Table l.-Continued

                                                                                         Radius of Max. Wind Forward Speed (T)                Representative Maximna Wind Speeds (Knots),
                      Coastal Location          Near City or                   CPI           (Nautical Miles)           (Knots)        Mean Radius of Max. Wind         .   Large Radius of Max. Wind
                    Zone   Mile   Let (*N)     Other Landmark             (In)    (mb)         RS   RM   RL        ST    MT    HT      V9x (RM) VX(ST) VX(MT) VX(HT) V,.(RL) V          x(ST) V.0U) V  x (UT)

                     A
                           1335      24                                   26.65   902.5         4     7  11        4     16    17         123     107     110      114        121       107    110     113
                           1280      25                                   26.77   906.5         4     8  12        4     10    17         119     105     108      112        119       105    108     ill
                           1215      26      Marco, Fla.                  26.91   911.3         4     9  14        4     11    17         117     103     106      109        116       102    106     109
                           1150      27      Lemon Bay,    Fla.           27.04   915.7         5     9  16        4     11    is         114     101     104      108        113       100    103     107
                           1085      28      Dunedin, Fla.                27.16   919.7         5   10   18        4     11    19         ill      98     102      106        110       98     101     105
                           1025      29      Yankeetown, Fla.             27.24   922.5         5   11   19        4     11    20         110      97     100      105        109       96      99     104
                            960      30      Carbur, Fla.                 27.31   924.8         6   12   21        4     11    21         107      95       98     103        106       94      97     102

                     B
                            900      29.7    Apalachicola, Fla.           27.34   925.8         6   12   22        4     11    28         107      94       98     106        106       93      97     105
                            840      31.5    Grayton, Beach, Fla.         27.36   926.5         6   12   22        4     11    28         105      93       97     105        104       92      95     104
                            780      31.6    Pensacola, Fla               27.36   926.5         6   12   22        4     11    28         105      93       97     105        104       92      95     204
                            720      30.3    Mobile, Ala.                 27.36   926.5         6   12   22        4     11    28         106      94       97     106        105       93      96     105
                            660      29.1    New'Orleans, La.             27.36   926.5         6   12   22        4     11    28         107      94       98     106        105       93      97     105
                            600      29.3    Lake Barre, La.              27.36   926.5         6   12   22        4     11    28         107      94       98     106        105       93      97     105
                            540      29.5    March Island, La.            27.36   926.5         6   12   22        4     11    28         106      94       98     106        k05       -93     97     105
                            480      29.7    Grand Chenier,,La.           27.34   925.8         6   12   22        4     11    28         107      94       98     106        106       93      97     105

                     C
                            420      30      Part Arthur, Tex.            27.31   924.8         6   12             4     11    28         107      95       98     107        106       94      97     106
                            360      29      Galveston, Tex.              27.28   923.8         6   11   20        4     11    28         109      96     100      108        108       95      99     107
                            300      29      Bay City, Tex.               27.24   922.5         5   11   19        4     11    28         110      97     100      109        109       96      99     108
                            240      28      San Antonio Vay,    Tex.     27.21   921.4         5   11   19        4     11    28         110      97     101      109*       109       97     100     109
                            180      27      Sarita, Tex.                 27.15   919.4         5   10   18        4     11    28         112      99     102      ill        Ill       98     101     110
                            120      26      Brownsville, Tex.            27.09   917.4         5   10   18        4     11    28         113     100     103      112        112       99     102.    Ill

                    CPI  - central pressure index, estimated minimum pressure
                    RS   - representative    small radius to region of maximum winds
                    RM   - representative    mean radius to region of maximum winds
                    RL   - representative large radius to region of maximum winds
                    ST   - representative slow speed of translation of hurricane center
                    MT   - representative moderate speed of translation of hurricane center
                    HT   - representative high speed of translation of hurricane center
                    T    - speed of translation of hurricane center
                    VgX  . maximum theoretical gradient wind computed for each CPI with Pn-29.92
                    Vx     estimated maximum 30-ft wind speed computed from V         x -0.865 V  gx + 0.5T

                              Table A.--Hurricanes with central pressure index less than 29.00 inches (1900-1967) ranked by CPI

                                                                                          Max. 30-ft wind                                                                          max. 30-ft wind
                                                                                          speed estimated                                                                          speed estimated
                                                                                          from analyses                                                                            from analyses
                       Date                 CH        R       vgx       Lat.         T       of data            Date                CH        R:                 IAt.          T      of data
                                                                                                                                                      vgX
                                           (in.)   (n.mi.) (kts)      (deg. N.)    (kts)       (kts)                               (in.)   (n.mi.) (kts)      (deg. N.) (kts)           (kts)

                                                         ZONE 1                                                                                   ZONE 3
                       Sept. 2, 1935       26.35      6       119       24.8         9                          Sept. 27, 1958     27.66     25       01         34.0       18
                       Sept. 9, 1919       27.44     15         94      24.8         8                          Oct. 15, 1954      27.66     36       80         33.0       26           82
                       Oct. 20, 1926       27.52     21         85      24.6       16                           Sept. 21, 1938     27.86     50       72         33.7          -
                       Sept.  10, 1960     27.55     22         -       24.5         9                          Sept. 14, 1944     27.88     17       98         35.2       23
                       Sept.  18, 1926     27.59     24         96      25.8       17                           Sept. 10, 1954     27.97      -        -          -            -
                       Sept.  16, 1928     27.62     53       102       26.7       13                           Sept. 16,1933      28.25     42       73         35.2          9
                       Sept.  17, 1947     27.76     34         89      26.2       10                           Aug. 28, 1958      28.26      -        -         34.0       17
                       Sept.  4, 1933      27.98     29         88      26.9       11                           Aug. 30, 1954      28.35      -        -         33.4          -
                       Sept.  15, 1945     28.09     24         86      25.5       10                           Sept. 11, 1960     28.35     36        -         37.4       30
                       Sept.  8, 1965      28.11     22         -       25.2       11                           Aug. 12, 1955      28.40     45       63         34.5          7
                       Sept.  28, 1929     28.15     28         85      24.9       10                           Sept. 19, 1955     28451     so       68         35.0          9
                       Aug. 26, 1949       28.16     23         86      26.7       14            78             Sept. 18, 1936     28.53     34       55         35.2       16
                       Oct.  17. 1950      28.20      -         -       25.8         6                          Aug. 23, 1933      28.63     36       50         36.9       18           53
                       Oct.  11, 1909      28.30     22         82      24.5       10                           Aug. 25, 1924      28.70     34       68         35 2       22
                       July  28, 1926      28.34     14         77      28.0         -                          Sept. 3, 1913      28.81     41       63         35:8       16;
                  oo   Sept. 22, 1948      28.41     16         74      26.8       11                           Aug. 24o 1949      28.86     24       70         33.5       22
                       Sept. 27, 1964      28.57      -
                                                                -       25.5         9                          Dec. 2, 1925       28.95,    54       54         34.2       14
                       Nov. 4, 1935        28.73      -         69       -           -                          Sept. 16,  1967    28.97      -        -         36.6          9
                       Oct.  20, 1924      28.83     .25        54      25.8         6                          Sept. 17,  1906    28.98     61       63         34.0       16
                       Sept. 11, 1903      28.84     43         66      25.8         8
                       Oct.  18, 1906.     28.84     35         58      26.9         6
                       Oct.  5, 1948       28.85     31         58      25.8       13                                                             ZONE 4
                       June  17, 1906      28.91     26         63      26.9       12                           Sept. 21,  1938    27.86     50       72         41.8       47           83
                                                                                                                Sept. 11,  1954    27.97      -        -         41.3       40
                                                          ZONE  2                                               Sept. 16,  1933    28.25      -       73          -            -
                                                                                                                Sept. 14,  1944    28.31     48       62         41.4       30           83
                       Sept. 26, 1958      27.52     19         -       32.7       12                           Sept. 11,  1960    28.35      -        -         38.0       32
                       Oct.  15, 1954      27.66     36         80      32.0                     82             Aug. 31, 1954      28.38     22        -         .41.8      33
                       Sept. 29, 1959      28.05     10         -       32.0       12           100             Sept. 18, 1936     28.53     34       55         38.0          -
                       July  28, 1926      28.34     14         77      28.4         8                          Aug. 26, 1924      28.70     66       51         41.3       29
                       Aug.  30,   1954    28.35      -         -        -                                      Aug. 29, 1958      28.73      -        -         39.0       21
                       Aug.  12,   1955    28.40     45         63      32.5         7                          Aug. 15, 1971      28.88      -        -         42.5       11           75
                       Oct.  19, 1968      28.47      -         -       31.0       17                           Sept. 9, 1969      28.91      -        -         43.8       40
                       Sept. 10, 1960      28.47     33         -       32.9       26
                       Sept.  19, 1955     28.51     50         68      32.8       10
                       Sept.  9, 1964      27.82     20         -       29.1         7           100
                       Oct. 15, 1947       28.59     13         63      32.1       17
                       Sept. 16, 1928      28.75      -         -       29.5         -
                       Aug. 11, 1940       28.78     27         67      32.0         9            90
                       Oct. 25, 1921       28.91      -         -       29.0       10
                       Sept. 15, 1945      28.91      -         -       29.0         -
                       Aug. 28, 1911       28.92     27         63      32.1         8

                                                                                                       Table A.--Continued

                                                                                                                                                                                                  Has. 30-ft wind
                                                                                                                                                                                                    speed estimates'
                                                                                                                                                                                                    from analyses
                                  Date                 CPI       R       vgx       T      Lat.        Long.       Date                 CPI        R      vgx        T       Lat.       Long.           of data
                                                     (in.)   (n.mi.) (kts)      (kts) (deg.N.) (deg.W.)                               (in.)   (n.mi.) (kts)      (kts)   (deg.N.)    (dej.W.)            Mts)
                                                                   ZONE A                                                                             ZONE B
                                  Sept. 2, 1935      26.35       6       119       9      24.8        90.9        Aug.  17,  1969     26.61     15       ill        -       28.6       88.5                130
                                  'Sept. 9, 1919     27.44       15       94       8      24.6        82.9        Sept. 8,   1900     27.64       -        90       -       27.0       90.5                77
                                  Oct. 20, 1926      27.52       21       97     16       23.8        81.3        Sept. 10, 1965      27.79     32         -      17        28.9       89.8
                                  Sept. 10, 1960     27.55       20       -        9      25.5        81.5        Sept. 29, 1915      27.70     29         92     10        29.9       90.1                74
                                  Sept..21, 1948     27.62       7        0        8      24.5        81.8        June  27, 1957      27.95     19         95     14        29.8       93.6                91
                                  Oct. 17, 1910      27.80       16       73-    11       24.5        82.5        Sept. 14. 1919      28.00       -               20        26.9       90.2
                                  Sept. 8, 1965      27.99       19       -      15       25.2        81.5        Sept. 20, 1926      28.20     17.        85       7       30.5       87.5
                                  Oct. 18, 1944      28.02       27       91     13       24.6        82.8        July  21, 1909      28.31     19         86       -       26.8       91.0
                                  Sept. 17. 1947     28.03       34       -        -      26.4        81.3        Aug.  25, 1926      28.31     27         87     10        29.6       90.7
                                  Sept. 18. 1926     28.05       24       -      17       26.5        81.0        Oct.  3, 1964       28.33     21         -        7       29.0       91.4
                                  Sept. 28, 1929     28.15       28       -      10       24.8        81.1        July  5, 1916       28.38     50         70     25        30.7       8&0
                                  Get. 25, 1921      28.29       18       70     10       28.1        82.8        July  31, 1936      28.46     19         70       9       30.5       86.5
                                  Oct. 11, 1909      28.30       22       82     10       @24.3       81.7        Sept. 28. 1917      28.48     33         70     13        30.4       87.2
                                  Sept. 16, 1928     28.30       53       -               2M          81.4        Sept. 27, 1906      28.50     73         72     16        30.6       88.5
                                  Sept. 4, @950      28.30       -        -        -      -29.1       83.1        June  16, 1934      28.52     37         70     16        29.9       91.7
                                  Aug. 26, 1949      28.37       23              14       27.2        81.2        Sept. 19, 1947      28.54     33         63     16        29.9       90.1                83
                                  Sept. 15. 1945     28.39       24       -      10       25.5        81.0        Aug.  14, 1901      28.72     33         72     14        29.9       90.1
                                  Oct. 6. 1964       28.47       -        -      15       24.0        83.0        Oct. 18, 1916       -28.76    19         70     21        30.4       87.2
                                  Sept. 4, 1933      28.48       29       -      11       27.8        81.6        Aug.  7, 1940 ,     28.76     11         62-      8       29.0       92.8
                                  June 9. 1966       28.64       -        -        9      30.0        84.3        Sept. 23, 1956      28.76     22         64     10        30.0       86.5                71
                                  Oct. 18, 1968      28.70       -        -      10       29.3        82.2        July  27, 1943      28.78     16         68       8       28.2       92.0
                                  Oct. 19, 1924      28.70       19       -        8      25.0        83.0        Sept. 30, 1929      28.80     65         61       6       30.1       85.7
                                  Nov. 4, 1935       28.73       -        69       -      25.0        81.0        Aug.  30, 1950      28.92     21         56     23        30.2       88.0
                                  Sept. 11, 1903     28.84       43       66       7      27.0        81.5        Sept. 21, 1920      28.93     28         58     28        29.6       90.7
                                  Oct. 18. 1906      28.84       35       58       6      25.0        81.0        Sept. @O, 1909      28.94     88         63     11        29.9       90.1
                                  Oct. 5, 1948       28.85       31       58     13       24.0        81.2        Oct.  7, 1941       28.98     Is         68     11        29.9       BC7
                                  Oct. 18, 1950      28.88       -        -        -      28.0        81.6        Sept. 15, 1960.     28.98                       10        28.1       89.0
                                  June 17, 1906      28.91       26       63       -      25.1        80.9
                                  Oct. 4, 1966       28.94       -        -        7      24.2        84.0                                             ZONE C
                                  Oct. 7, 1941       28.98       is       68     11       29.8        84.7        Sept. 20, 1967      27.26     25       118        8       26.0       97.1                95
                                                                                                                  Sept. 11, 1961      27.64     20         -        6       27.2       94.9
                                                                                                                  Sept. 8. 1900       27.64     14         90     10        29.2       95.9                77
                                                                                                                  Aug.  13, 1932      27.83     12         94     15        29.1       95.6
                                                                       Legend                                     Aug.  3. 1970       27.85       9      113      14        27.9       97.2
                                                                                                                  June  27,  1957     27.95     19         83     14        29.2       93.8
                                                       CPI - central pressure index                               Aug.  18,  1916     28.00     35       101      11        27.5       97.5
                                                       R    - radius of maximum winds                             Sept. 14, 1919      28.00       -        -      20        27.7       97.5
                                                       V gX - maximum gradient wind speed                         Sept. 5, 1933       28.02     20         91       8       25.9       97.5
                                                       T    - forward speed of the storm                          Aug.  30, 1942      28.07     18         77     14        28.5       96.7
                                                                                                                  Aug.  16,  1915     28.14     32         72     11        29.8       95.0                63
                                                                                                                  June  22,  1921     28.17     17         84     11        29.7       95.4
                                                                                                                  July  21,  1909     28.31     19         86     12        29.0       96.0
                                                                                                                  Sept. 23, 1941      28.31     21         70     13        29.7       95.4
                                                                                                                  Aug.  27, 1945      28.57     is         77       4       29.0       96.2
                                                                                                                  June  28, 1929      28.62     13         71     15        28.5       96.5
                                                                                                                  Sept. 11, 1970      28.73       -        -      11        23.9       96.3
                                                                                                                  Aug.  7, 1940       29.76     11         62       8       29.9       93.9
                                                                                                                  July 27, 1943       28.78     16         68       8       29.5       95.0
                                                                                                                  Aug.  4, 1933       28.80     25         66     10        25.9       97.5
                                                                                                                  Sept. 161, 1971     28.85       -        -      15        29.4       93.2
                                                                                                                  Oct.  4. 1949       28.45     28         68     11        28.9       95.4                71
                                                                                                                  Sept. 10, 1971      28.91       -                 5       28.5       96.0                80

                              Table B.-Average direction of center movement of all tropical storms in the zone                                                     which reached
                                                                        hurricane intensity at any time (1887-1971)

                                          Avg. Direction of                         Avg. direction of                         Avg. direction of                         Avg. direction of
                                                movement                                  movement                                  movement                                  movement'
                                             within zone                               within zone                               within zone                                within zone
                       Date                   (degrees to)       Date                   (degrees to)       Date                   (degrees to)       Date                   (degrees to)

                                                       ZONE 1                                                                              ZONE  2

                       Aug. 18,  1887             306            Aug.  6, 1928 -            318            Aug.  20, 1887             018            July  21, 1934              215
                       Aug. 15,  1888             302            Sept. 15, 1928             303            Aug.  22, 1887             353            Aug.  10, 1940              .304
                       Sept. 3,  1888             192            Sept. 25, 1929             235            Octi; 10, 1888             052            Aug.  2, 1940               234
                       Sept. 7,  1888             272            Aug.  28, 1932             297            Sept. 9,  1888             031            Sept. 18, 1941              029
                       Aug. 23,  1891             289            Sept. 5, 1932              348            Oct.  12, 1893             355            Oct.  8, 1941               107
                       Oct. 11,  1893             318            Oct.  4, 1933              056            Aug.  26. 1893             346            Get.  19, 1944              016
                       Aug. 26,  1893             323            Aug.  31, 1933             286            Sept. 25, 1894             Oil            Aug.  1, 1944               350
                       Sept. 25, 1894             005            Sept. 2, 1933              299            Oct.  8, 1894              050            June  24, 1945              060
                       Oct. 20, 1895              030            July  29, 1933             293            Oct.  9, 1896              043            Sept. 16, 1945              016
                       Sept. 4, 1896              047            Sept. 6, 1934              328            Aug.  30, 1898             332            July  5, 1946               354
                       Oct. 9, 1896               049            Aug.  31, 1935             287            Oct.  1, 1898              300            Oct.  141, 1947             274
                       Aug. 1, 1898               290            Sept. 28, 1935             037            Oct.  30, 1899             000            Sept. 22, 19,48             058
                       Oct. 28, 1899              021            Nov.  3, 1935              237            Aug.  13, 1899             017            Sept. 5, 1950               345
                       Aug. 11, 1899              324            July  27, 1936             287            Oct.  20, 1904             318            May 16, 1951                019
                  Eli  Aug. 9, 1901               296            Oct.  5, 1941              287            Sept. 13, 1904             307            Oct.  2. 1951               302
                  C)   Aug. 10, 1903              291            Sept. 17, 1941             003            Oct.  19, 1906             213            Aug. 29. 1052               322
                       Sept. 11, 1903             293            Sept. 14, 1945             306            June  17, 1906             302            Sept. 21, 1953              068
                       Oct. 15, 1904              010            Sept. 12, 1946             025            July  28, 1908             001            Oct.  14, 1954,             094
                       June 16, 1906              032            Oct.  11, 1947             051            Oct.  18, 1910             015            Aug.  29, 1954              021
                       Oct. 17, 1906              036            Sept. 16, 1947             241            Aug.  26, 1911             295            Aug.  16, 1955              318
                       Sept. 30, 1908             002            Sept. 21, 1948             051            July  13, 1916             326            Aug.  11, 1955              348
                       July 27,  1908             336            Oct. 5, 1948               044            Oct.  25, 1921             075            Sept. 19, 1955              349
                       Oct. 11,  1909             052            Aug. 25, 1949              299            Sept. 29, 1920             043            Sept. 26, 1958              325
                       Nov. 21,  1912             034            Oct.  17, 1950             339            Sept. 22, 1920             314            Sept. 10, 1960              030
                       Nov. 15,  1916             062            Oct.  2, 1951              053            Sept. 16, 1924             060            Sept. 24, 1963              040
                       Sept. 7,  1919             270            May 17, 1951               125            Nov.  30, 1925             035            Sept. 9, 1964               218
                       Oct. 20,  1924             076            Oct. 24, 1952              052            July 26, 1926              335            June  5, 1968               343
                       Oct. 20,  1926             056            Sept. 10, 1960             315            Sept. 17, 1928             022            June  19, 1968              060
                       July 26,  1926             324            Aug.  27, 1964             345            Sept. 9, 1930              047            Aug.  10, 1968              034
                       Sept. 17, 1926             305            Sept. 8. 1965              270            Sept. 6, 1934              005            Oct.  19, 1968              043
                       Aug. 12, 1928              309            June  17, 1968             333                                                      Aug.  8, 1969               033
                                                                 Aug. 9. 1968               315

                                                                                               Table B.-Continued

                                              Avg. direction of                           Avg.-direction of                           Avg. direction of                           Avg. direction of
                                                    Movement                                    sovement                                            t                                   movemat
                                                  within zone                                within some                                 within zone                                  within zone
                         Date                      (degrees to)       Date                     (degrees to)       Date                   @(degrees  to)      Date                    ..(de$reds  to)
                                                             ZONE 3                                                                                  ZONE 4
                         Aug.  20, 1887                047            July 21     1934             247            Oct.  20, 1887               017           Sept. 16,    2933              044
                         Oct.  20, 1887                035            Sept. 7, 1934                023            Aug.  21, 1888               068           Sept. 8, 1934                  017
                         Oct.  11, less                038            Sept. 5. 1935                066            Sept. 10, 1888               *044          June 19, 1934                  057
                         Nov.  25, 1888                024            Sept. 17, 1936               339            Oct. 11, 1888                045           Sept. 6. 1935                  069
                         Sept. 24, 1889                057            Sept. 20. 1938               273            Now. 26, 1888                034           Sept. 18. 1936                 0"
                         Sept. 11, 1889                314            Aug. 31, 1940                025            Sept. 20, 1889               278           Sept. 24, 1936                 015
                         July 8, legi                  069            Aug. 16, 1940                037            Sept. 24, 1889               045           Sept. 21, 1938                 007
                         Oct.  11, 1891                015            Sept. 22, 1941               029            Oct. 12, 1891                040           Sept. 1, 1440                  027
                         Aug.  23, 1893                358            Oct. 8, 1941                 108            July 8. 1891                 066           Oct. 17; 1943                  007
                         Oct.  4. 1893                 104            Oct. 19, 1944                022            Aug. 23, 1893                003           Oct.-20, 1544                  647'
                         Oct.  13, 1893                006            Aug. 1, 1944                 358            Oct. 9, 1894*                032           Aug. 2. 1944                   061
                         Sept. 26, 1894                043            Sept. 13, 19"                008            Sept. 9, 1896                357           Sept. 14, 1944                 033
                         Oct. 9, 1894                  041            June 25. 1945                038            Aug. 19, 1899                064           June.26, 1945                  046
                         Oct.  30, 1899                004            Sept.  '17. 1945             013            June 29, 1902                098           Sept. 21,1950                  042
                         Aug.  15, 1899                034            July 5, 19"                  045            Oct. 12, 1902                066           Aug. 14, 1953                  046
                         July  10, 1901                256            Oct. 9, 1946                 086            Sept. 15, 1903               @332          Sept. 6. 1953                  019
                         Oct.  10. 1903                022            Aug. 23, 1949                035            Oct. 11, 1903                059           Aug. 30, 1954                  015
                         Sept. 15, 1903                347            Aug. 19, 1950                033            Sept. 14, 1904               039           Sept. 10, 1954                 030
                         Sept. 14, 1904                329            Oct. 3, 1951                 040            Sept. 15, 1912               078           Auj. lb, 1955                  074
                         Sept 16, 1906                 292            May 20, 1951                 025            July  20, 1916               028           Sept. 270 1956                 055
                         July  30, 1908                036            Aug. 13..1953                013            Sept..6, 1918                020           Aug. 29, 1958                  045
                         Oct.  19, 1910                058            Sept. 27, 1953               058            Sept. 30, 1920               022           Sept. U, 1960                  .028
                         Oct.  5, 1912                 241            Oct. 15. 1954                002            Aug.  25, 1924               028           Sept. 18, 1962                 046
                         Sept. 1, 1913                 315            Aug. 30, 1954                029            Dec.  3, 1925                068           Oct. 21. 1968                  032
                         July  19, 1916                012            Sept. 10, 1954               024            Aug.  23, 1927               034           Sept. 9, 1969                  030
                         July 13, 2916                 320            Aug. 11, 1955                012                                                       Aug. 12. 1969                  050
                         Sept. 22 1920                 315            Sept. 18, 1955               015                                                       Aug. 15, 1971                  033
                         Sept. 30: 1920                025            Aug. 16, 1955                324
                        ,Oct. 23, 1923                 348            Sept. 27.1956                050
                         Sept. 16, 1924                313            Aug. 28, 1958                045
                         Aug. 25, 1924                 284            Sept. 27. 1958               010
                         Dec. 1, 1925                  284            Sept. 11, 1960               028
                         Aug. 23j 1927                 003            Sept. 28, 1962               036
                         Sept. 17, 1928                306            Sept. 20, 1963               320
                         Sept. 11. 1930                304            Sept. 16, 1967               018
                         Aug. 22, 1933                 322            Aug. 11, 1968                067
                         Sept. 15, 1933                016            Oct. 20, 1968                043
                                                                      Sept. 9. 1969    -           040
                                                                      Sept. 30, 1971               315

                                                                                                      Table B.-Continued

                                                         Avg. direction of                            Avg. direction of                           Avg. direction of                             Avg. direction of-
                                                               m
                                                                   am t                                     Movement                                    movement                                      movement'
                                                                  ov   n'
                                                             within zone                                 within zone                                  within zone                                  within zone
                                    Date                     (degrees to)         Date                    (degrees to)         Date                   (degrees to)          Date                    (degrees to)

                                                                        ZONE A                                                                                   ZONE R
                                    Sept. 5, 1900                  217            Sept. 2, 1935                335           Sept. 7, 1900                 292            Sept.  29f 1929               000
                                    Aug. 10, 1901                  290            Nov. 4, 1935                 270           Aug. 12, 1901                 .325           Aug.  31, 1932                315
                                    Sept. 11, 1903                 292            Nov.  7. 1935                084           Oct. 9, 1902                  020            Aug.  2. 1933                 269
                                    Sept. 17, 1904                 10             July  28. 1936               303           Sept. 12, 1903                350            July  23, 1934                270
                                    June 16, 1906                  350            Aug.  2, 1938                250           Sept. 26, 1906                332            June  15. 1934                359
                                    Oct. 16. 1906                  038            Sept. 16, 1941               272           Aug. 10, 1911                 318            Aug.  26, 1934                295
                                    Oct. 10, 1909                  020            Oct. 6, 1941.                320           Sept. 11, 1912                315            Sept. 4. 1935                 000
                                    'Oct. 17, 1910                 002            Oct.  16. 1944               010           June 12_1912                  050            Nov.  7, 1935                 075
                                    Aug. 9. 1911                   325            June  23, 1945,              059           Sepit. 3, 1915                000            July  30, 1936                327
                                    Sept. 11, 1912                 294            Sept. 15, 1945               000           Sept. 28, i915                355            Aug.  4. 1938                 296
                                    Sept. 2, 1915                  327            Oct.  7, 1946                010           Oct. 17, 1916                 005            Oct.  6, 1941                 000
                                    Now. 15, 1916                  055            Sept. 17, 1947               289           July 4. 1916                  350            Aug.  18, 1942                304
                                    Nov. 9, 1919                   275            Aug. 18, 1947                276           Sept. 27, 1917                025            July  25, 1943                273
                                    Sept. 29, 1920                 065            Oct.  11, 1947               038           Aug. 6, 1918                  328            Sept. 19, 1943                   32
                                    Octi 24, 1921                  050            Oct.  4, 1948                040           Nov. 12, 1919                 280            Sept. 18, 1947                303
                                    Oct. 19, 1924                  060            Sept. 20, 1948               010           Sept. 21, 1920                350            Aug. 22. 1947                 315
                                    Nov. 30. 1925                  041            Aug. 26, 1949                325           Sept. 29, 1920                060            Sept. 3, 1948                 020
                                    July 28, 1926                  311            Oct.. 20, 1950               030           Oct. 15. 1923                 010            Oct. 18, 1950                 211
                                    Sept. 18, 1926                 300            Sept. 2. 1950                018           Sept. 13. 1924                035            Aug. 29. 1950                 005
                                    Sept. 16, 1928                 330            Oct. 18, 1950                338           Sept. 19, 1926                308            Sept. 25, 1953                041
                                    Aug. 8, 1928                   310            Oct. 1, 1951                 090           Aug.  24, 1926                000            Sept. 13, 1960                000
                                    Aug. 12, 1928                  321            Sept. 10, 1960               330           Aug.  9, 1928                 310            Oct.  3, 1964                 .355
                                    Sept. 27, 1929                 315            Oct. 14, 1964                040           Aug.  13, 1928                344            Sept. 10, 11965               315
                                    Sept. 7, 1930                  047            Sept. 8, 1965                280                                                        Aug.  17, 1969                340
                                    Aug. 29, 1932                  296            June 9. 1966                 346
                                    July  30, 1933                 270            Oct. 4, 1966                 080                                               ZONE C
                                    Sept. 1, 1933                  284            June 4, 1968                 030
                                    Oct. 4, 1933                   024            Oct. 18, 1968                053           Sept. 7, 1900                 305            Aug.  17, 1936                236
                                    Sept. 3, 1933                  325            May 24, 1970                 018           June  24, 1902                005            June  26, 1936                318
                                    July 22, 1934                  247                                                       July  20, 1909                276            Aug.  14, 1938                340
                                                                                                                             Aug.  27, 1909                292            Aug.  27, 1938                270
                                                                                                                             Sept. 13, 1910                000            Aug.  6. 1938                 307
                                                                                                                             June  11, 1912                018            Sept. 22, 1941                346
                                                                                                                             Oct.  15, 1912                319            Aug. 20, 1942                 299
                                                                                                                             June  27, 1913                295            Aug. 29, 1942                 313
                                                                                                                             Aug.  16, 1915                345            July  26, 1943                302
                                                                                                                             Aug.  18, 1916                290            Sept. 15. 1943                025
                                                                                                                             Aug.  6, 1918                 325            Aug. 24, 1945                 000
                                                                                                                             Nov.  13,   1919              270            Oct.  22, 1947                308
                                                                                                                             Sept. 6,    1921              320            Oct.  3, 1949                 000
                                                                                                                             June  20, 1921                346            June  24, 1954                316
                                                                                                                             June  13, 1922                305            Sept. 4. 1955                 280
                                                                                                                             June  28, 1929                320            June 27, 1957                 003
                                                                                                                             Aug.  12, 1932                329            Sept. 11, 1961                .330
                                                                                                                             Aug.  3, 1933                 255            Sept. 20, 1967                332
                                                                                                                             July  6, 1933                 240            Aug. 3, 1970                  203
                                                                                                                             Sept. 3, 1933                 278            Sept. 11, 1970                270
                                                                                                                             July  24, 1934                270            Sept. 16, 1971                037
                                                                                                                             Aug.  26. 1934                212            Sept. 10, 1971                260

                                                          ad SPH

                                                                                                                                 tow 14*
                                                      J
                                                                                                                             _46-
                                                                                                                                                                              Vi, 04:
                                                                          &Qqj60)
                                                                          R=XG
                                                  W@33

                                                                                                                                                                                     71
                         1) as
                                                                                                                                                                                                   L
                                                                                                                                                                                        i :j
                        AL

                                                                                                                                                         _7  @j -7
                                                                                                                                                                                                      1-L J-
                                          JL                                  41

                                                                                                                                                                                                                 4

                                                                     R=zo

                                                                                                                                                                           -no I I Tip
                                                  NMR[ Rot N&33@-A.,@,                                                                                           .3                                      7i4@@ 4
                                                                                                                                                                            1;_1   :7 1

                                                                                                                                    V --- Wind speed at point
                                                                                                                                    V --Maximum wind speed
                                                                                                                                    Rt Radi    of maximum wind
                                                                                                                                    r-Radial distance of point
                                                                                                                                    Revised SPH from nomogram (Fig. 12)
                                                                 74= @21

                             0                                     6
                                                                                                      ",?c/&-t(V,,* R.Adil        Disiay'lce

                                                                          Fig. 1---COMPARISON OF WIND PROFILES IN HURRICANES

                                                             X Revi c4 SPH

                           VX NMRP fyk N& .33
                     so

                     40-

                                                                                  For mean radius of maximum wind(RM)
                                                                                  and moderate storm speed(MT).

                       23   1            6   17    X15  I'l   30    31   31    55    SA-        .36   57         -3-1 40    '+l        43
                                                            V.

                                          N. .3

                               Fig    2.--MAXIMUM WIND SPEED (V      X  ALONG ATLANTIC COA     ST (Revis  ed SPH and NHRP No. 33)

                               7-9

                             in
                               A7
                             iL

                             Ul:

                                                                   10    20   30 40
                                             Frequency per.-100 years
                                                   -- VI+,

                                ATIVE FREQUENCIES@OF,@@
                  Fig. 3. - - cumuL                        E CENTRAL FRESSURES(1900-1971) ZONE I

                                                      25

                        2.7

                                   0.1                   5     10    20   so   .0
                                        Frequency per 100 years

          Fig. 4-cumuLATIVE FRE   QUENCIES OF HURRICANE CENTRAL PRESSURES (1900-197 1) ZONE 2

                                                 26

                               ;zq

                             w

                             (A
                             iL127

                             J

                             cr

                               26

                                           0.1         1,         5    10     Lo   30  40
                                               Frequency per 100 years
                                                                        o & F/4-

                   Fig. 5, CUMULATIVE FREQUENCIES    OF HURRICANE CENTRAL  PRESSURES(1906m--1971)ZONE 3

                                                           27

                       29

                      r
                     @J-

                     @e 27
                     0.

                                                               10     20  so   40
                                       Frequency per 100 years

           Fig. 6.--CUmULATIVE FREQUENCIES OF HURRICANE CENTRAL PRESSURES (1900-197 1) ZONE 4

                                                 28

                               LU

                               w
                               OL

                                 2.7

                               u 2(0

                                             0.1           1         5     10     ID   30   40  50
                                                  Frequency.per 100  years

                    Fig   7.-- CUM  UL,ATIVE FREQUENC.IES OF HURRI CANE CENTRAL PkESSURES(1900-1971)ZONE A

                                                              29

                       z
                       LLI

                                                            5    10     20   so  @o
                                         Frequency per 100 years

            Fig. 8.-- CUMULATIVE FREQUEliCIES OF HURRICANE CENTRAL PRESSURES (1900-197 1) ZONE B

                                                    30

                               7-9

                               28

                            H

                            lu

                               27

                               2AG

                                                                     10     10   30  40
                                              Frequency per 100 years

                 Fig. 9.--'CUMULATIVE FREQUENCIES'OF HURRICANE  CENTRAL PRESSURES(1900-1971)ZONE C

                                                         31

                                                     ----------------

                                                                                                                                                                                                                                                                       @r             44-
                                                                                                                                                                                                                               --t-d
                                                                                                             %0I
                                                                                                                    I a                                                                                                                                                                     41-4

                                                                                                                                                                                                                                                                           op
                                     29

                                                                                                      -- - --------- T- -----=
                                                                                                                                                                                                          4 -      4-

                                                                                                                                                                                                   j7

                                                                                                                                                                                             -4-A -
                                                                                                                                                                                                             07@     L
                                                                                                                                                                                                                                                                        I J@o

                                                                                                                                                                           7
                                 171

                                                                                                                                                                                                                  71

                                                                                                                                                                                                                                                                                                1     17

                                                                                                                                                                                                                                                              it  i I

                                                                                                                                                                                                         L

                                 41
                                 je
                                     2.7

                                                                                000
                                 u

                                                                                                                                        f                                                                                                                               i4
                                     26
                                                                                                                                                                                                                     -7- 1
                                                                                                                                                                                                                                                                                   -FIT

                                        9-3                                      Z7                                        31                                        56                                         3q
                                                                                                                                                                L &t Ctude              (DeBroes                     N)                                                                             47

                                                Fig.        10.--LATITUDINAL VARIATION                                         OF AVERAGE FREQUENCY PER                                      100 YEARS                OF      CPI,        ATLANTIC               COAST ZONES

                                                                . ..... . .. ..

                                                                                                                                                 t7--
                                                                                                                                                                                                                                   7  I      -,I @-7

                               29
                                            oc.c        FzREKc
                                                                                                                                                                                                                                                                                       46

                                                                                                                                                                                                                                                                      p
                            0)

                            M                                                                                                                                                                                                                                                                                      7.

                                                                                                                                                                                                                              77

                             03

                                                                     ZoNe

                                                                                                                                                                                                                                                                               7:-

                               2ro

                                                                                                                                                                                                                                                                                              4:
                                                                                                                                                rooo                                                                                                            1200
                                   0                                   200                                 400
                                                                                                                                                                 'n            ulfpwcoaLsL,(-n,-m0                        '0'0                                                                         400
                                                                                                                                 Dis-t&rpc;e              Alo-9

                                         Fig.         ll.--GEOGRAPHICAL VARIATION                                              OF AVERAGE FREQUENCY                                   PER 100             YEARS           OF CPI,               GULF COAST ZONES

                                                                 Distance -F-rovn Center (-a. w%L.)
                                         400          300     250          0         15,0      Azo         /00                          60

                                                                                                                                           0

                                                                                                                                          30

                    400

            U4
                  300

                                                                                                                                         -7

                                                                                                                                          6
                                                         A                                                                             -4
                                /1-0 loo       80       60    So     440                   zo -16                        Cl
                      od          O-Z          0-3          0-4-        0.5          0.6         0.7          0.8          0.9           /.o
                                                               Wi-nal aa@to (V/vx)

                                                    Fig. 12.--NOMOGRAM FOR DETERMINING WIND PROFILE

                                           HUR:7-84-

                                              Noymerarn i

                        NHRP RPT K*3-:@

                                                                                                       tA

                             z          4      57    6           8     G1                lz    13
                                             RactLa I    D L@i a-n c e-

                                 Fig. 13.--COMPARISON OF RELATIVE WIND FIELD PROF ILES FOR ZONE C

                   Q

                   QL 30-

                     125         26'         27           ZL9         31 LtLt,2.'            35          37          39          41          43          49

                         Fig. 14.--VARIATION OF P WITH LATITUDE IN STORMS AND ADOPTED VARIATION
                                                                  -n

                                                      A0

                                                      Ila

                                                      too- -

                                                      qo--

                                                                                rim
                                                      70

                                                   V 64

                                                    .940
                                                    j       HHRP FWr W3
                                                      30    FLS. 2-3,
                                                                                                        El
                                                                        For mean radius of maximum wind (RH)
                                                                        and moderate storm speed(mr).
                                                             ,20   40    40    so    100   110   140   160   180 2.00    zzo

                                      Fig. 15.--COMPARISON OF WIND FIELD PROFILES FOR ZONE 1

                                                                                   36

                                                                                                                 7:: !.:1:.

                                                                                                                      -1:71

                                      60

                                                                                                                  j

                                      40

                                      310                   Lat-30-514                                                 ba

                                                             For:mean.radjus of max@=sm wind(RK)
                                                             an@ moderate storm sp@ed()@r).
                                                                   __j - ----- J-
                                       0     20   40    60    80    /00    Mo   140   1 (66 too 200     120   240 A60
                                                                       Ractiad    Dis+.aviep- On. YnQ

                                        Fig.   16.@-COMPARISON      OF WIND   FIELD PROFILES-FOR        ZONE 2

                                         loco

                                         Co

                                         70

                                                 Rp  RP0633
                                               F@2-

                                         30

                                         20

                                                              For mean rodiu: of maximza wind(XK)
                                            \tv

                                                              and moderate 6 orm speed(Xr
                                                20   40   60    80   100   1         160 1w 200 X@ft-'
                                                                 RaodLal. Dt,+=.6 (-n. -"U)

                                        Fig.   17.--COMPARISON      OF WIND FIELD      PROFILES    FOR ZONE 3

                                                                          37

                              q0
                                                                                                                                      17

                                                                                                                                                  t

                          -4
                              -7

                                                                              r-SPH

                                                                                                                       7-
                           4D

                          -a40                fig. as Lat. 46-5@

                              to
                                                                  'For mean radius of maxim-m wind(RM)
                                                                   and moderate storm speed(MT).
                                      ZO      40      60     SID     100 /240       140     160 180 ZOO           120    246     266 Aso        3iz7-
                                                         Radia I        Dis+avica Oet. ynz.)

                                        Fig. 18.--COMPARISON OF WIND                     FIELD PROFILES           FOR ZONE-      4

                                                  9                        Ammmk $PH

                                                 .(ft  5b

                                                             NJM, Rrr
                                                              Fis- 13 -1, M.Ull I
                                                     30

                                                                      For  mean radius of maximas wind(M)
                                                                      and  moderate storm speed(MT).
                                                     oil

                                                                 40     so    go /,00     110 140     160 180 2PO Z20
                                                                                                        6".

                                       Fig. 19---COMPARISON                OF WIND FIELD PROFILES FOR                   ZONE A

                                                                                   38

                                    110
                                                                                                                         ss:
                                                                                                                        T

                                                                                                          -T-77    -'7-'

                                                                                                                         7

                                                                                                          7--             71-7,-l
                                    p

                                                                           IRA

                                  J44                                                                                            --4

                                   30-
                                                    4-3

                                     10
                                                                 For mean radius   of maximum wind(
                                                                 and moderate storm  speed(Mr).
                                      0    to    40    60    so     /00 IAO /40 /60 ISO 200 220 Zo                  260   260   3aa
                                                                           Distance (-et. vni)

                                           Fig. 20.--COMPARISON OF WIND              FIELD    PROFILES FOR       ZONE   B

                                               70

                                              060                                                                        7
                                             Ql,l

                                                       70"s C, MUM2

                                               20

                                               10
                                                 E

                                                                    For mean radius of maximum wind(SH)
                                                                    and moderate storm speed(Kr).
                                                            4"     60         100 120 /4V      160   1" 2"       12.0 2000
                                                                        R&AAi Distance (VI.ML),
                                          Fig. 2  -1.--COMPARISON       OF WIND FIELD PROFILES FOR              ZONE C

                                                                                  39

                                                     LL.
                                                                       0

                                                                           01@

                                                                               Vol

                                                            60
                                                                 50
                                                                                30
                                                                                            20KTS

                                                                                    101P
                                                                                         0#41

                     Fig. 22.---!EXAMPLE OF REVISED SPH WIND FIELD, ZONE C
                                 Mean radius of maximum wind and moderate storm speed.

                                                      40

              1.0

              o.q

        4:@

           14
           4j
            cc
              o.3-

             0.2

             0.1 -

              01      1
                    0-1       0-2-       0.3        0.4        0.6        0-6         0.7.       0.8        0.9
                                                    Relative RaAial Distance(r/R)

                Fig. 23.--VARIATION OF WINDSPEED (V/V x  WITH RADIAL DISTANCE (r/R) WITHIN THE RADIUS OF MAXIMUM WIND

                                                  ju
                    V                                                WIN01 FROFILr=.
                    J:NsipF- RM                43                     OurSIDE RM

                                                  so

                                                XL

                                                  40

                                        I     I     pal         I
                      0     2-          6     8 -nJhL.        40         180
                                               Ra4ial Distance

                                                   05
                                       0.7                      0.3          y
                                                                 40AIft
                                Ole                                  0,21

                                   lirts.                 MS.

                                  Fig. 24.--EXAMLE OF WIND FIELD CONSTRUCTION

                                                        42

                                            .8S    .8         .7        .6        .5

                        .98

                                                                                               .3

                        1.00

                                                      .-rat-
                        .95

                                                                                               .02

                                                                                                0

                         .7                                                                    .02.

                          .6                               .3         .2     .15      .7

                                      Fig. 25
                                      NGKOGRAM FOR WIND FIELD ASSYMETRY FACTOR
                                          Values are ratio of storm speed(T) to be
                                          subtracted from maximum wind profile.

                                                             43

                                                                           3 6668 14102 5629