[Federal Register Volume 60, Number 239 (Wednesday, December 13, 1995)]
[Notices]
[Pages 64020-64028]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-30246]
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DEPARTMENT OF COMMERCE
National Weather Service; Automated Surface Observing System
SUBJECT: Notice of Intent.
SUMMARY: The National Weather Service (NWS) implemented the
Supplemental Data Program effective October 1, 1995. This program
supplements data provided by the Automated Surface Observing System
(ASOS). Observations produced through the Supplementary Data Program
are transmitted separately from the ASOS operations and provide data to
support hydrometeorological operations and climatological applications.
This notice explains the reasons for the shift in reporting methods and
describes how to obtain and interpret hydrometeorological information
that was previously available in the surface aviation observation (SAO)
format.
EFFECTIVE DATE: October 1, 1995.
ADDRESSES: Requests for information should be sent to Steve Pritchett,
NWS, Office of Systems Operations, 1325 East-West Highway, Silver
Spring, MD 20910 or through electronic mail at suppdata
@smtpgate.ssmc.noaa.gov.
FOR FURTHER INFORMATION CONTACT:
Steve Pritchett at 301-713-1792.
SUPPLEMENTARY INFORMATION: As part of the NWS modernization, the NWS is
undergoing a major shift in the methods used to observe and report
surface weather information.
The NWS has developed and is installing ASOS to automate certain
observing functions, thereby taking advantage of advances in sensor and
microprocessor technology. At approximately 900 airports in the United
States during the 1990s, the U.S. Departments of Commerce,
Transportation, and Defense are deploying ASOS to support aviation
operations and weather forecasting and warnings, as well as general
needs of the hydrometeorological, climatological, and meteorological
research communities.
ASOS will provide greatly expanded coverage (locations and
observing hours), objective observations, a continuous weather watch,
and improved operating efficiency. ASOS, when integrated with advances
in remote sensing and weather information processing systems, is
expected to contribute to improved warning and forecast services. ASOS
will perform the basic observing functions necessary to generate a SAO.
However, because some weather parameters observed manually today will
not initially be observed by ASOS, the NWS is introducing two new
classes of observations to the array of meteorological surface
observations: the supplementary data observation (SDO) and the
supplementary climate data (SCD).
Supplementary observations are not appended to the ASOS
observation; rather, they are disseminated as separate messages. The
NWS will disseminate these reports to a variety of Federal and non-
Federal users of NWS data. Supplementary data will be made available
through NWS communication systems such as Family of Services, NOAA
Weather Wire, and various computer and commercial vendor services.
Surface observational data in the ASOS era will continue to come
from many sources. ASOS, along with complementary data derived from
remote sensing technologies, such as statellites, will form the
backbone of the surface observing network (SAO) system. Surface data
from over 20,000 automatic and manual hydrometerological sites,
including cooperative and hydrologic networks, will continue to play an
important role in NWS operational forecast programs. They comprise the
climatological data bases and supply information to users who currently
rely on surface observations from airports, as well as for non-aviation
related information.
The NWS Weather Forecast Offices (WFOs) will issue these new
supplemtary data reports. The SDOs will provide significant, event-
driven observations primarily intended to support weather forecasting
and general hydrometeorological needs. Elements may be reported in SDOs
on an ``as-observed'' basis and do not imply a continuous or basic
weather watch. SDOs will not generally include elements that are in
augmented ASOS observations from that location.
The SCD reports may provide routinely scheduled observations useful
for climatological applications, as well as hydrometeorological
operations. SCDs are routinely issued at designated hours at about the
same time as the recorded surface observation (note: the SDOs are
issued on an event basis, which may fall ``on the hour'' only by
chance).
Most offices issuing SCDs and SDOs will not issue the full suite of
SCD/SDO elements. There will be some variation among individual offices
in the elements they report. Elements reported in SCDs will generally
not be reported in SDOs. Exceptions are: (1) precipitation type and
intensity reported in SCDs may also be reported in SDOs when considered
significant by the on-site observer, and (2) volcanic ash reported in
SCDs will also be reported in SDOs. Observations of volcanic eruptions
and volcanic ash when first noted and severe weather (severe
thunderstorms and tornadic
[[Page 64021]]
activity) when first observed may be included in weather warnings and
statements issued by cognizant NWS offices rather than in supplementary
data reports. The same elements may be reported in both SDO's and
aviation observations from some sites (see enclosures).
In the future, non-Federal observers (volunteers, Cooperative
Observers, etc.) are expected to participate as members of the
supplementary data network. Their reports will focus on snow depth,
snowfall amount, hail and ice pellet occurrences. It is expected that a
subset of volunteer observers will report water equivalent of snow on
the ground.
Susan F. Zevin,
Deputy Assistant Administrator for Operations.
Report Format and Content
The information in supplementary data reports will follow the
syntax and abbreviations used in Federal Meteorological Handbook Number
1 for Surface Observations (FMH-1). (FMH-2 for synoptic cloud reports)
where practical. Supplementary data reports differ from surface
aviation observations in the following ways:
Only a limited set of observed elements is included in
supplementary data reports. A given supplementary report may contain
one or several elements.
Supplementary data reports are not issued on an hourly
basis. Time-scheduled SCDs are issued at main synoptic hours or at
other designated hours of the day depending on the variable(s) being
reported. Event-driven SDOs are issued when a significant phenomenon is
first observed. A follow-up ``termination'' SDO will be issued after
the cessation of certain events.
Some SDOs will contain a ``/'', solidus remarks separator.
The purpose of the remarks separator is to help computer decoders
differentiate between decodable (parsable) remarks and remarks not
readily amendable to decoding. SCDs will not inclde the ``/'' remarks
separator because all remarks in SCDs are decodable.
Supplementary data reports are encoded as follows:
SID--TYPE--(COR--)TIME--WX/--Decodable RMKS--/--Other RMKS (``--''
indicates a required space and ``/'' indicates a required solidus. The
``/'' will appear in an observation if and only if one or more ``WX''
elements are reported and are followed by remarks. The ``/'' remarks
separator will appear in an SDO, only if, the SDO contains both
decodable and noncodable remarks.
SID--Station identifier (3 to 5 alphanumeric characters).
TYPE--Type of observation (either SCD or SDO). If the observation is a
correction to a previously disseminated SCD or SDO, the contraction COR
will follow the type of observation (in which case the time (TIME) will
be the time of the observation being corrected).
TIME--Time of observation in hours and minutes UTC [0000 * * * 2359].
WX--Weather and/or obstructions to vision. This field will be from 1 to
15 characters in length including the precipitation intensity symbol
(-,+). The elements to be reported in the ``WX'' field are given in
Table 1 of this guide. Contractions for precipitation types are given
in Table 2; contractions for obstructions to vision are in Table 3.
Decodable RMKS, Other RMKS--Remarks are separated from the ``WX''
group with a solidus and a space. If no ``WX'' is reported, the remarks
are preceded with a space after the time (TIME) element.
SCD remarks are encoded in the following order:
8NNhCLhCMCH--Total cloud cover and synoptic cloud
types
931nnn--Depth of new snow (snowfall)
933RRR--Water equivalent of snow on the ground
4/sss--Depth of snow on ground
98xxx--Duration of sunshine
7R24R24R24R24--Calendar day total precipitation
(from designated sites)
4snTxTxTxsnTnTnTn--Calendar day
maximum and minimum temperature (from designated sites)
NIL--Nothing to report
SDO remarks are encoded in the following order:
Temination reports for ``WX'' elements (e.g., END IP)
SNOINCR x/x--Snow increasing rapidly
HLSTO x--Size of largest hailstone observed
`` / '' remarks separator
Other SDO remarks when considered significant by the on-site staff:
Local variation in visibility (e.g., VSBY N2; F BANK N-E2) (designated
stations)
Virga--Precipitation evaporating before reaching ground (designated
stations)
Precipitation not at station (e.g., RWU SW; SU OVR MTNS N) (designated
stations)
Clouds above 12,000 feet (types and/or layers) (designated stations)
Distant clouds obscuring mountains (designated stations)
Other meteorological information considered significant, such as
blowing volcanic ash
The SDO ``WX'' group, remarks of snow increasing rapidly (SNOINCR),
hailstorms (HLSTO), and termination reports for ``WX'' elements are
considered decodable.
Initiation and termination reports will be issued for selected
``WX'' elements (those listed in Table 2 of this guide). An exception
is hail, for which only an initiation report will be issued.
Termination reports will be issued for any weather and/or obstructions
to vision previously reported in the ``WX'' field of an SDO when the
event is determined to have ended. Termination reports are not required
for information reported in SDO remarks unless designated by NWS
regional headquarters.
The initiation report for a ``WX'' element is implicit in
the ``WX'' field (e.g., ``MCI SDO 1325 BS'' is an initiation report for
blowing snow). The initiation report for other significant events
carries the information in the SDO remarks section (e.g., ``MCI SDO
1325 BD/ RWU SW'' may be an initiation report for distant rain showers.
The blowing dust, previously reported, continues).
Termination reports contain the key word ``END'' followed
by a space and a description of the event which ended. All termination
information, even for a ``WX'' element, is considered to be in the
remarks category. Termination information for ``WX'' elements precedes
any `` / '' remarks separator (e.g., ``MCI SDO 1445 END BD / END RWU
SW'').
Termination reports for items listed under ``other SDO
remarks when considered significant by the on-site staff'' can have
several meanings: (1) the event ended, (2) the event is no longer
considered significant, but it may still exist, or (3) because of
darkness, it is not possible to determine if the event still exists.
Plain language remarks may at times be necessary to clarify
changing local conditions. For example, if a fog bank previously
reported to the north (e.g., ``ANC SDO 1205 F BANK N2'') moves over the
airport, ``ANC SDO 1330 F BANK MOVD OVR ARPT'' might be subsequently
reported.
Location of phenomena within 10 miles of the station will be
reported as ``VCNTY STN,'' followed by the direction from the station.
Phenomena between 10 and 30 miles of the station will be located by
direction from the station. Phenomena beyond 30 miles will be reported
as ``DSNT,'' followed by the direction from the station.
If there are no coded remarks or weather to report in a scheduled
SCD,
[[Page 64022]]
the SCD will be transmitted with ``NIL'' (e.g., ``PHL SC 1758 NIL'').
Table 1 gives the type of supplementary information reported, the
category of the supplementary data report, criteria for reporting, and
type of site making the report. It also gives the syntax of the element
and one or more examples. Examples of complete supplementary data
reports are given in the back of this guide. Except where explicitly
stated otherwise, the ``WFO'' column refers to all WFOs, whether or not
they have a collocated ASOS. The ``Other NWS Office'' column refers to
NWS staffed or manual observing sites with responsibility for
supplementary data reporting. This table represents the initial
supplementary data reporting configuration by office type (augmented
elements are excluded).
Table 1.--Description of Elements Reported as Supplementary Data
--------------------------------------------------------------------------------------------------------------------------------------------------------
Type of report Reported by
Element ---------------------------------------- When reported -------------------------------------- Format, example,
SDO SCD WFO Other NWS offices comments
--------------------------------------------------------------------------------------------------------------------------------------------------------
WX--Weather and/or obstructions .................. X................. at 6-hrly X................ Designated Format: Table 2 gives
to vision. Volcanic ash will synoptic times Stations. contractions for
--All precipitation types and not be included (00, 06, 12, and precipitation types;
intensities. in SCDs from 18 UTC) and Table 3 gives
--Volcanic ash................. sites with a staff is contractions for
collocated ASOS. available. obstructions to
vision.
Where: ``WX'' refers
to weather and
obstructions to
vision. Weather
refers to
precipitation and
tornadoes.
Obstructions to
vision refer to
phenomena that reduce
visibility but are
not precipitation.
Weather and
obstruction to vision
elements included in
SCDs and SDOs are
given in the
``Element'' column to
the left.
Examples: VOLCANIC
ASH; IF; HLSTO \1/4\;
IP-: END VOLCANIC
ASH; END IF
Comments: Visibility
specified by FMH-1
for qualifying
intensity of snow and
drizzle may not be
well resolved at
certain WFOs without
a collocated ASOS.
Consequently, snow
and drizzle
intensities reported
by non-ASOS WFOs must
be considered to be
estimates. A follow-
up ``termination''
SDO will be issued
upon termination of
the event (with the
exception of hail).
The termination SDO
will give the event
preceded by the key
world ``END.''
Volcanic ash will not
be reported in
supplementary data
originating from
sites which have
collocated ASOS.
Volcanic ash is
appended directly to
the ASOS observations
at those sites.
Visibility will not be
a factor in reporting
``VOLCANIC ASH'' as
present weather (WX)
in an SDO. Any
observed ``VOLCANIC
ASH'' will be
reported.
[[Page 64023]]
WX--Weather and/or obstructions X................. .................. when observed and X................ Designated ......................
to vision. Volcanic ash will staff is stations.
--Ice pellets.................. not be included available.
--Volcanic ash................. in SDOs from
--Other nonaugmented elements sites with a
when considered significant by collocated ASOS.
the on-site staff (ice
crystals, ice fog, smoke,
blowing snow, blowing sand,
blowing dust, and blowing
spray).
Daily total sunshine duration.. .................. X................. Once daily at 08 Reported at ................. Format: 98xxx.
UTC. If the official NWS Where: ``98'' is the
station is sunshine- code group indicator
closed at 08 duration and ``xxx'' gives the
UTC, the reporting sites. total minutes of
``98xxx'' group These sites may sunshine for the
will be reported be moved as previous calendar
in the first 6- required. day. ``xxx'' is
hrly observation encoded in hundreds,
after opening. tens, and units.
Equipment must Example: 98096; 98000.
be available. Interpretation: 96
minutes of sunshine;
0 minutes of
sunshine.
Missing data
indicator: 98///.
Calendar day total prescription .................. X................. 24-hour value Only reported by ................. Format: 7R24R24R24R24.
accumulation (water once daily at 00 WFOs which do Where: ``7'' is the
equivalent). LST and staff is not have a code group indicator;
available. collocated ASOS. R24R24R24R24 gives
precipitation amount
encoded in tens,
units, tenths, and
hundredths of inches.
Example: 70125.
Interpretation: 1.25
inches of
precipitation (water
equivalent) in the
preceding 24 hours.
Missing data
indicator: 7////.
Comment: Note that in
the SCD the ``7''
group refers to a 24-
hr precip total
ending at midnight
LST whereas the ``7''
group in the remarks
of an ASOS
observation or a
manual surface
observation refers to
a 24-hr precip total
ending at 12 UTC.
Calendar day maximum and .................. X................. 24-hour value Only reported by ................. Format:
minimum temperatures. once daily at 00 WFOs which do 4s,TxTxTxsnTnTnTn.
LST and staff is not have a Where: ``4'' is the
available. collocated ASOS. code group indicator;
sn gives sign of the
data (``1'' for
temperatures below 0
deg.F, ``0'' for
temperatures 0 deg.F
or higher); TxTxTx is
the maximum
temperature in whole
degrees F; TnTnTn is
the minimum
temperature in whole
degrees F.
Example: 400700045.
Interpretation: 24-hr
max temperature of 70
deg.F, 24-hr min
temperature of 45
deg.F.
Missing data
indicator: 4////////.
[[Page 64024]]
Snow increasing rapidly........ X................. X................. Hourly when snow Designated Designated Format: SNOINCR x/x.
depth increase stations. stations. Reference: FMH-1 Table
equals or A3-88, 2.e modified
exceeds 0.5''/hr to exclude the depth
and staff is increase since the
available. last 6-hrly report.
Where: ``SNOINCR'' is
the code group
indicator. ``x/x''
gives the snow depth
increase in the past
hour/total depth of
snow on the ground at
time of observation,
both of which are
reported in whole
inches.
Example: SNOINCR 1/6.
Interpretation: One
inch depth increase
in the past hour with
6 inches on the
ground at time of
observation.
Size of largest hailstone X................. .................. when first Designated Designated Format: HLSTOx.
observed. observed and stations. stations. Where: ``HLSTO'' is
staff is the group indicator.
available. ``x'' gives the
diameter (in inches)
of the largest
hailstone observed.
Hailstone size is
reported in \1/4\
inch increments. If
the hailstone size is
less than \1/8\ inch,
it will be encoded as
<\1/4\.
Example: HLSTO \1/2\.
Interpretation: The
largest hailstone
observed was \1/2\''
in diameter.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Other Significant Weather Information
--------------------------------------------------------------------------------------------------------------------------------------------------------
Significant local variations in X................. .................. when observed and Reported at ................. Format: Description
visibility. staff is specific, and direction from
available. currently station.
staffed NWS Examples: VSBY N2; F
observing sites Bank N-E2.
which are Interpretation: (1)
determined to be Visability to the
especially north is 2 miles. (2)
problematic with A fog bank exists
respect to north through east.
terrain, and Comment: Once
multiple reported, significant
visibility changes to ``local
sensors are not variations in
available or do visibility'' will be
not suffice. reported in updated
SDO reports.
Virga.......................... X................. .................. when observed and Reported at ................. Format: ``VIRGA'' and
staff is specific, direction from
available.. currently station.
staffed NWS Example: VIRGA NW.
observing sites Comment: Once
in mountainous reported, significant
areas lacking changes to ``virga''
radar coverage will be reported in
which are updated SDO reports,
determined to be e.g., VIRGA VCNTY STN
especially NW MOVG E.
problematic with
respect to
terrain.
[[Page 64025]]
Precipitation not at the X................. .................. when observed and Reported at ................. Format: Type and
station. staff is specific, intensity (or ``U''
available. currently if unknown) of
staffed NWS precipitation and
observing sites direction from
in mountainous station.
areas lacking Examples: RWU SW; SU
radar coverage OVR MTNS N.
which are Comment: Once
determined to be reported, significant
especially changes to
problematic with ``precipitation not
respect to at the station'' will
terrain. be reported in
updated SDO reports,
e.g., RWU VCNTY STN
SW MOVD NW.
Significant clouds above 12,000 X................. .................. When observed and Reported at ................. Format: ``CLD LYR''
feet AGL and significant cloud staff is specific, followed by one or
types. available. currently more cloud base
staffed NWS heights (generally
observing sites estimated, hundreds
in mountainous of feet AGL) and
areas which are amounts (SCT, BKN, or
determined to be OVC). Ceiling
especially designators (``E''
problematic with and ``M'') are not
respect to reported as this
terrain. layer may not be the
layer constituting a
ceiling. Only
significant cloud
layers above 12,000
feet AGL are
reported. Types of
significant clouds
associated with
orographic features,
such as ACSL and
rotor clouds, may
also be reported.
Example: CLD LYR 140
OVC; ACSL VCNTY STN
SW-W
Interpretation: A
significant overcast
cloud layer based at
14,000 feet above
ground level was
observed.
Comment: Once
reported, significant
changes to ``cloud
layers above 12,000
feet'' and
``significant cloud
types'' will be
reported in updated
SDO reports, e.g., CB
W MOVD N.
Significant distant clouds X................. .................. When observed and Reported at ................. Format: Description
obscuring mountains. staff is specific, and direction from
available. currently station.
staffed NWS Example: CLD BASES
observing sites OBSCG MTNS W.
which are Interpretation: Cloud
determined to be bases obscuring
especially mountains to the
problematic with west.
respect to Comment: Once
terrain. reported, significant
changes to ``distant
clouds obscuring
mountains'' will be
reported in updated
SDO reports.
Any other meteorological X................. .................. When observed and X................ X................ Format: Plain language
information when considered staff is using FMH-1
significant by the on-site available. contractions where
staff. practical.
Comments: Any
significant weather
information such as
convective cloud
types not covered
above may be entered
here if not included
in an ASOS
observation.
[[Page 64026]]
Depth of new snow.............. .................. X................. At 6-hrly Designated Designated Format: 931nnn.
synoptic times stations. stations. Where: ``931'' is the
(00, 06, 12, and code group indicator
18 UTC) when any for the amount of
amount of snow solid precipitation
has fallen in (i.e., snow, snow
the past 6 hours pellets, snow grains,
and staff is ice pellets, ice
available. crystals, and hail)
that fell in the past
6 hours, even if some
or all of it melted.
``nnn'' gives the
depth in the frozen
state to the nearest
tenth of an inch
using a leading zero
if less than 1 inch.
Trace amounts are
reported as 931000.
Example: 931012.
Interpretation: 1.2
inches of new snow
fell in the past 6
hours.
Missing data
indicator: The group
is not reported if no
solid precipitation
fell during the past
6 hours or if hail
was the only form of
solid precipitation.
Water equivalent of snow on the .................. X................. Once daily at 18 Designated Designated Format: 933RRR.
ground. UTC if the stations. stations. Where: ``933'' is the
average snow code group indicator
depth (to the and ``RRR'' is the
nearest inch) is water equivalent of
2 inches or more snow on the ground
and staff is reported in tenths of
available. inches.
Example: 933125.
Interpretation: 12.5
inches water
equivalent of snow on
the ground.
Missing data
indicator: Not
reported if no solid
precipitation fell
during the past 6
hours or if hail was
the only form of
solid precipitation.
Depth of snow on the ground.... .................. X................. At 6-hrly Designated Designated Format: 4/sss.
synoptic times stations. stations. Where: ``4/'' is the
(00, 06, 12, and code group indicator
18 UTC) and for depth of snow on
staff is the ground at
available. See observation time.
comments. ``sss'' gives the
snow depth encoded in
whole inches with
leading zeros.
Example: 4/009.
Interpretation: The
snow depth at
observation time was
9 inches.
Missing data
indicator: Not
reported if the
frozen precipitation
was comprised
exclusively of hail.
Comments: Report at 00
and 12 UTC whenever
there is more than a
trace of snow on the
ground and at 06 and
18 UTC if there is
more than a trace of
snow on wht ground
and more than a trace
of precipitation
(water equivalent)
occurred within the
past 6 hours.
[[Page 64027]]
Synoptic total cloud cover and .................. X................. At 6-hrly Designated ................. Format: 8NNh CL hCM
cloud types (low cloud base synoptic times stations. CH.
height; low cloud amount; low, (00, 06, 12, and Reference: FMH-2
middle, and high cloud types). 18 UTC) unless paragraph 4.2.7
the sky is clear. modified to include
``N'' (total cloud
cover) as described
in FHM-2 paragraph
4.2.2.1 and ``h''
(height of lowest
cloud) as described
in FMH-2 paragraph
4.2.1.3.
Where: ``8'' is the
code group indicator.
``N'' is total
fraction of oktas
(eighths) of the
celestial dome
covered by clouds,
where ``9''
represents sky
obscured by fog and/
or other
meteorological
phenomena and ``/''
in the ``N'' position
means cloud cover is
indiscernible for
reasons other than
fog or other
meteorological
phenomena, or the
observation was not
made. Nh gives the
total amount (oktas)
of all CL clouds. If
there are no CL
clouds, Nh gives the
total amount of all
CM clouds. Otherwise
Nh=0. Nh=9 for sky
obscured by fog and/
or other
meteorological
phenomena. Nh=/ for
cloud cover
indiscernible for
reasons other than
fog or other
meteorological
phenomena, or if the
observation is not
made. CL, CM, and CH
are types of low,
middle, and high
clouds respectively.
``0'' is coded for
clouds absent, except
that ``/'' is coded
in the cloud layer
subfield(s) above on
overcast layer if the
types are not
determinable. ``h''
gives the height with
respect to the
surface of the base
of the lowest cloud
seen. It is a single
digit coded in
accordance with FMH-
2. Table 3-3. ``h''
and CL CM CH are
coded with ``/'' if
there is a total
surface based
obscuration which
prevents an
observation of the
clouds.
Example: 8220850.
Interpretation: N=2
oktas total cloud
cover. Scattered
middle clouds (Nh=2
oktas cloud coverage
and CL=0) with bases
between 7,000 and
8,000 ft AGL (h=8);
no low clouds; middle
clouds are
altocumulus
progressively
invading the sky; no
high clouds.
Missing data
indicator: The ``8''
group is not reported
for clear skies.
--------------------------------------------------------------------------------------------------------------------------------------------------------
----------------------------------------------------------------------------------------------------------------
Precipitation types
-----------------------------------------------------------------------------------------------------------------
Weather Contraction Weather Contraction
----------------------------------------------------------------------------------------------------------------
Rain................................. R...................... Snow................... S
Rain Showers......................... RW..................... Snow Showers........... SW
Drizzle.............................. L...................... Snow Pellets........... SP
Freezing Rain........................ ZR..................... Snow Grains............ SG
Freezing Drizzle..................... ZL..................... Ice Crystals........... IC
Ice Pellets.......................... IP..................... Hail................... A
Ice Pellet Showers................... IPW.................... ....................... .......................
----------------------------------------------------------------------------------------------------------------
[[Page 64028]]
Table 2.--Precipitation Types and their Contractions
----------------------------------------------------------------------------------------------------------------
Obstructions to vision
-----------------------------------------------------------------------------------------------------------------
Obstruction Contraction Obstruction Contraction
----------------------------------------------------------------------------------------------------------------
Volcanic ash......................... VOLCANIC ASH........... Blowing Sand........... BN
Ice Fog.............................. IF..................... Blowing Dust........... BD
Smoke................................ K...................... Blowing Spray.......... BY
Blowing Snow......................... BS..................... Fog.................... F
Ground Fog........................... GF..................... Dust................... D
Haze................................. H...................... ....................... .......................
----------------------------------------------------------------------------------------------------------------
Table 3.--Obstructions to Vision and their Contractions
Examples of Supplementary Data Reports
CAESCDCHS
TTAA00 KCHS DDHHMM
CHS SCD 1758 IP-/ 8872// 931024 933009 4/009
This SCD shows the occurrence of weather (ice pellets) along with
coded remarks. 8872// indicates overcast low clouds (ragged shreds of
stratus or cumulus associated with precipitation) with low cloud base
height of 400-600 ft. 931024 represents a 6 hour snowfall amount of 2.4
inches. The water equivalent of snow on the ground was 0.9''. The snow
depth (4/009) at time of observation was 9 inches.
PHLSCDPHL
TTAA00 KPHL DDHHMM
PHL SCD 0455 70050 400700045
This SCD, issued at midnight EST, is from a WFO which does not have
a collocated ASOS. The 24-hour precipitation total (70050) was 0.50
inches water equivalent. The 24-hour maximum and minimum temperatures
were 70 deg.F and 45 deg.F respectively.
BISSCDBIS
TTAA00 KBIS DDHHMM
BIS SCD 0755 98096
This SCD from a network sunshine duration station reports 96
minutes of sunshine for the previous calendar day.
STLSDOMCI
TTAA00 KMCI DDHHMM
MCI SDO 0642 IP-
This SDO reports the onset of light ice pellets.
STLSDOMCI
TTAA00 KMCI DDHHMM
MCI SDO 0729 END IP
This SDO reports the cessation of ice pellets.
PHLSDOACY
TTAA00 KACY DDHHMM
ACY SDO 0759 SNOINCR \1/2\
This SDO indicates snow depth increase at a rate of more than 0.5
inches/hour. The snow depth increased 1 inch during the past hour. Two
inches of snow were on the ground at observation time.
PHLSDOACY
TTAA00 KACY DDHHMM
ACY SDO 2036 HLSTO \3/4\
This SDO reports a hail occurrence with the largest observed
hailstone size of \3/4\ inch.
SEASDOSMP
TTAA00 KSMP DDHHMM
SMP SDO 1756 END IP / RWU CAD LYR 140 OVC
This SDO was reported from a mountainous site where terrain is
problematic. Ice pellets ended. Rain showers of unknown intensity were
observed to the southwest. There was a significant overcast cloud layer
based at 14,000 feet above the observer's ground level. The ``/ ''
remarks separator separates decodable and nondecodable remarks.
DENSDODEN
TTAA00 KDEN DDHHMM
DEN SDO 1056 CLD BASES OBSCG MTNS W
This SDO was also reported from a mountainous site where terrain is
problematic. Clouds were observed obscuring mountains to the west.
/D ANC SDO HHMM
ANC SDO 1310 IF=
This SDO shows the initiation of ice fog. Notice that a different
communications header and message ending code (=) are used in Alaska.
/D ANC SDO HHMM
ANC SDO 1645 END IF=
This SDO terminates the ice fog event.
[FR Doc. 95-30246 Filed 12-12-95; 8:45 am]
BILLING CODE 3510--12-M