National Weather Service: Modernization Activities Affecting Northwestern
Pennsylvania (Letter Report, 09/26/97, GAO/AIMD-97-156).
Pursuant to a congressional request, GAO examined how the National
Weather Service (NWS) had implemented modernization and restructuring
activities in northwestern Pennsylvania, focusing on identifying: (1)
why the Erie, Pennsylvania, weather service office (WSO) was spun down
prior to the Department of Commerce's October 1995 report on 32 areas of
concern; (2) what types of services were provided to the counties served
by the Erie office before and after office spin-down, as well as what
public concerns have been raised, and how NWS responded to them; (3)
what safety concerns have been raised to weather services at the Erie
airport and to the timeliness of small-craft advisories for Lake Erie,
including how NWS responded to public concerns about these issues; and
(4) whether any reliable statistical or other evidence exists that
addresses whether a degradation of service in the Erie area has occurred
as a result of the modernization and office restructuring.
GAO noted that: (1) NWS started spinning down the Erie WSO by
transferring warning responsibilities to the three assuming Weather
Forecast Offices (WFO) in August 1994 before the Department of Commerce
began its review of the 32 areas of concern in June 1995; (2) concerns
about the Erie office closure, however, were made known as early as June
1994; (3) NWS continued with its plans to spin down the office because
officials believed that they would be providing the best service to the
area by relying on modernized radars in other offices; (4) the three
WFOs that assumed responsibility for the counties formerly served by the
Erie WSO provide generally the same types of services that the Erie
office had provided, with the exception of the general public's local or
toll-free telephone access to NWS personnel; (5) the major concerns
surrounding the transfer of responsibilities relate to whether radar
coverage over the counties formerly served by Erie would be adequate,
and whether forecasts and warnings are at least equal in accuracy and
timeliness to those previously issued by Erie; (6) NWS responses to such
concerns include analyzing its ability to detect severe weather
phenomena over northwestern Pennsylvania, as well as providing data on
how well the assuming offices are issuing forecasts and warnings; (7) a
few concerns also have been raised regarding NWS service to the Erie
airport and the timeliness of small-craft advisories for Lake Erie; (8)
the most commonly voiced concern regarded an automated surface observing
system (ASOS) and requirements for air traffic controllers to augment it
with human observations; (9) the Federal Aviation Administration (FAA)
has sponsored a study of the impact of its augmentation responsibilities
at airports such as Erie and will be issuing a report in the fall of
1997; (10) several studies present evidence that a degradation in
service has not occurred in northwestern Pennsylvania; however, the
ability to detect and predict lake-effect snow remains a concern; (11)
NWS is completing a lake-effect snow study to determine the
effectiveness of the modernized weather system in detecting and
forecasting lake-effect snow; (12) the Director of NWS' Office of
Meteorology told GAO that he will recommend a radar for the Erie area;
and (13) however, NWS has not yet taken a position on the need for a
radar, and the Secretary of Commerce is scheduled to make the final
decision on any action to be taken in northwestern Pennsylvania.
--------------------------- Indexing Terms -----------------------------
REPORTNUM: AIMD-97-156
TITLE: National Weather Service: Modernization Activities
Affecting Northwestern Pennsylvania
DATE: 09/26/97
SUBJECT: Weather forecasting
Meteorological research
Radar equipment
Warning systems
Federal agency reorganization
Federal downsizing
Air traffic control systems
IDENTIFIER: Pennsylvania
NWS Automated Surface Observing System
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Cover
================================================================ COVER
Report to Congressional Requesters
September 1997
NATIONAL WEATHER SERVICE -
MODERNIZATION ACTIVITIES AFFECTING
NORTHWESTERN PENNSYLVANIA
GAO/AIMD-97-156
National Weather Service: NW Pennsylvania
(511422)
Abbreviations
=============================================================== ABBREV
ASOS - Automated Surface Observing System
FAA - Federal Aviation Administration
NEXRAD - Next Generation Weather Radar
NOAA - National Oceanic and Atmospheric Administration
NRC - National Research Council
NWS - National Weather Service
WFO - weather forecast office
WSO - weather service office
Letter
=============================================================== LETTER
B-276777
September 26, 1997
The Honorable F. James Sensenbrenner, Jr.
Chairman, Committee on Science
House of Representatives
The Honorable Phil English
House of Representatives
As you know, the National Weather Service (NWS) has been modernizing
its systems and work processes since the 1980s to enable it to
provide better weather services to users. This effort is one of the
larger systems modernization programs within the federal government,
projected to cost about $4.5 billion. The modernization is vital to
NWS streamlining and downsizing and includes cutting its number of
field offices by over half. Before any weather service office is
closed, the Secretary of Commerce must certify that the affected
geographic areas will not experience a degradation of weather
service.\1
In your March 5, 1997, letter, you expressed concerns about radar
coverage and weather services provided to northwestern Pennsylvania,
an area that had been served by the Erie weather service office
(WSO). This office is slated for closure and has therefore been spun
down operationally (i.e., it is no longer providing operational
services to the public).\2 However, data from the Erie radar have
been used by one of the three NWS offices now providing services to
northwestern Pennsylvania. These offices are weather forecast
offices (WFOs) in Pittsburgh and State College, Pennsylvania, and
Cleveland, Ohio. NWS has not officially closed the Erie office,
however, because of ongoing concerns regarding services to the Erie
area. NWS officials said they will not close the office until they
have addressed all concerns about possible degradation of service,
including those regarding adequate radar coverage.
As agreed with your offices, we examined how NWS had implemented
modernization and restructuring activities in this area.
Specifically, our objectives were to identify (1) why the Erie,
Pennsylvania, WSO was spun down prior to the Department of Commerce's
October 1995 report on 32 areas of concern,\3 (2) what types of
services were provided to the counties served by the Erie office
before and after office spin-down, as well as what public concerns
have been raised, and how NWS responded to them, (3) what safety
concerns have been raised relating to weather services at the Erie
airport and to the timeliness of small-craft advisories for Lake
Erie, including how NWS responded to public concerns about these
issues, and (4) whether any reliable statistical or other evidence
exists that addresses whether a degradation of service in the Erie
area has occurred as a result of the modernization and office
restructuring.
--------------------
\1 This certification is required by the Weather Service
Modernization Act, Public Law 102-567, Sec. 706(b), 106 Stat. 4306
(1992).
\2 Spin-down is a term used by NWS to describe the actions taken at a
weather office slated for closure. It includes transferring weather
service responsibilities to other offices and reducing staff.
\3 This report was required by a joint agreement between the
Department and concerned members of the Congress. It assessed the
possibility of degradation of service in areas of concern identified
by the public primarily because of planned office closures.
Northwestern Pennsylvania was identified as an area of concern.
SCOPE AND METHODOLOGY
------------------------------------------------------------ Letter :1
To determine why the Erie WSO was spun down before completion of the
Secretary of Commerce's report on 32 areas of concern, we analyzed
documents that described the spin-down and reviewed the Secretary's
report. We also discussed the timeline of these events with NWS
officials.
To determine what weather services were provided before and after the
Erie office was spun down, we reviewed NWS site implementation plans
for the Cleveland, Pittsburgh, and Central Pennsylvania weather
offices, and interviewed former employees of the Erie WSO and
officials at each of the three WFOs. We also discussed the services
provided and concerns raised about the quality and types of services
with (1) members of Save Our Station, a group dedicated to saving the
Erie WSO, (2) Erie television station meteorologists, (3) the
National Air Traffic Controllers Association safety representative at
Erie International Airport, (4) officials at Presque Isle State Park,
Erie, (5) the officer in charge of the U.S. Coast Guard Station in
Erie, and (6) emergency management officials and representatives of
emergency volunteer organizations, such as Skywarn, in each of the
nine counties that constituted the Erie WSO warning area.\4 We
reviewed NWS' responses to concerns raised.
We identified safety concerns raised regarding the weather services
provided at the Erie airport and obtained NWS' responses to these
concerns through interviews with the National Air Traffic Controllers
Association safety representative at Erie International Airport, the
manager of the Aviation Weather Requirements Division, the Federal
Aviation Administration (FAA), and NWS officials. To identify
concerns raised about small-craft advisories on Lake Erie, we
interviewed (1) officials at Presque Isle State Park, (2) the officer
in charge of the U.S. Coast Guard station in Erie, (3) the commander
of the Greater Erie Boating Association, and (4) members of Save Our
Station. We reviewed NWS documents relating to aviation weather and
the small-craft advisories on Lake Erie and obtained NWS' responses
to safety concerns.
To determine if reliable statistical or other evidence existed that
addressed degradation of service, we reviewed NWS verification
statistics for severe weather events in the nine counties included in
the Erie WSO county warning area prior to and after spin-down of the
Erie office. We discussed the methodology and process used to
develop these statistics, and their reliability, with NWS officials.
In addition, we discussed NWS verification statistics and studies
with a professor emeritus and an associate professor of meteorology
at Pennsylvania State University and also with the chairperson of the
Modernization Transition Committee. Further, we reviewed available
NWS lake-effect snow study reports.\5 We interviewed the NWS Eastern
region team responsible for the lake-effect snow study and the
director of the Office of Meteorology at NWS headquarters. In
discussions with representatives of Save Our Station, county
emergency management directors, and volunteer organizations, we
obtained specific examples of weather events that these individuals
believed demonstrated evidence of degradation of service.
In addition, we reviewed the National Research Council (NRC) report
on NWS modernization and the Secretary's report on 32 areas of
concern, with specific reference to radar coverage. To understand
the ability of NWS' new radars and other data tools available to
forecasters to provide adequate coverage for severe weather event
warnings and lake-effect snow, we discussed this topic with NWS
officials and the study director of NRC, the chairperson of the
Modernization Transition Committee, a member of the Secretary's
report team who was the acknowledged expert on NWS radar, the former
chairperson of NRC's Modernization Committee (who is also a professor
emeritus of meteorology), and an associate professor of meteorology
at Pennsylvania State University.
We performed our work at NWS headquarters in Silver Spring, Maryland;
at the NWS Eastern region in Bohemia, New York; at the Cleveland,
Pittsburgh, and Central Pennsylvania WFOs; and at the Erie WSO. In
addition, we conducted telephone interviews with emergency management
officials and emergency volunteers in the Erie WSO county warning
area.
We performed our work from April to August 1997, in accordance with
generally accepted government auditing standards. As agreed with
your offices, we did not assess the adequacy of the NWS responses to
identified concerns, and we did not assess the adequacy of reports
discussed in this report. The Secretary of Commerce provided written
comments on a draft of this report. These comments are discussed at
the end of this report and are reprinted in appendix II.
--------------------
\4 Counties in the Erie WSO warning area were Cameron, Crawford, Elk,
Erie, Forest, McKean, Potter, Venango, and Warren.
\5 Lake-effect snow is localized snow that occurs over and along the
shoreline of lakes. It is caused by the flow of relatively cold air
over warm water, such as that occurring along the southern and
eastern shores of the Great Lakes during outbreaks of arctic cold
air.
RESULTS IN BRIEF
------------------------------------------------------------ Letter :2
NWS started spinning down the Erie WSO by transferring warning
responsibilities to the three assuming WFOs in August 1994 before the
Department of Commerce began its review of the 32 areas of concern in
June 1995. Concerns about the Erie office closure, however, were
made known as early as June 1994. NWS continued with its plans to
spin down the office because officials believed they would be
providing the best service to the area by relying on modernized
radars in other offices.
The three WFOs that assumed responsibility for the counties formerly
served by the Erie WSO provide generally the same types of services
that the Erie office had provided, with the exception of the general
public's local or toll-free telephone access to NWS personnel. These
ongoing services include issuing public forecasts, marine and
aviation forecasts and warnings, and severe weather warnings, and
conducting warning preparedness activities. The major concerns
surrounding the transfer of responsibilities relate to whether radar
coverage over the counties formerly served by Erie would be adequate,
and whether forecasts and warnings are at least equal in accuracy and
timeliness to those previously issued by Erie. NWS responses to such
concerns include analyzing its ability to detect severe weather
phenomena over northwestern Pennsylvania, as well as providing data
on how well the assuming offices are issuing forecasts and warnings.
A few concerns also have been raised regarding NWS' service to the
Erie airport and the timeliness of small-craft advisories for Lake
Erie. The most commonly voiced concern regarded an automated surface
observing system (ASOS) and requirements for air traffic controllers
to augment it with human observations.\6
While FAA accepted responsibility for the Erie system from NWS in
October 1996, concerns about using air traffic controllers to augment
ASOS are not limited to the Erie airport. Consequently, FAA has
sponsored a study of the impact of its augmentation responsibilities
at airports such as Erie and will be issuing a report in the fall of
1997.
Several studies present evidence that a degradation in service has
not occurred in northwestern Pennsylvania; however, the ability to
detect and predict lake-effect snow remains a concern. Studies by
NRC and the Department of Commerce show that the assuming WFOs have
the ability to detect most weather phenomena in the areas formerly
served by Erie as well as or better than that office. NWS is
completing a lake-effect snow study to determine the effectiveness of
the modernized weather system in detecting and predicting this
phenomena in the Erie area. Preliminary conclusions indicate that
service has not been degraded in detecting and forecasting
lake-effect snow; however, the service being provided to Erie is not
as good as the service provided to other lake communities whose
service has improved as a result of the NWS modernization. The
director of NWS' Office of Meteorology told us that as a result, he
will recommend a radar for the Erie area. However, NWS has not yet
taken a position on the need for a radar, and the Secretary of
Commerce is scheduled to make the final decision on any action to be
taken in northwestern Pennsylvania.
--------------------
\6 ASOS was implemented during modernization to replace human
observation of many elements, such as wind speed and direction, and
visibility. However, because the system cannot detect all elements
that were historically reported through human observation, such as
thunderstorms, tornadoes, and cloud layers above 12,000 feet, system
augmentation is needed to report these elements.
BACKGROUND
------------------------------------------------------------ Letter :3
NWS began a nationwide modernization program in the 1980s to upgrade
observing systems, such as satellites and radars, and design and
develop advanced forecaster computer workstations. The goals of the
modernization are to achieve more uniform weather services across the
nation, improve forecasts, provide better detection and prediction of
severe weather and flooding, permit more cost-effective operations
through staff and office reductions, and achieve higher productivity.
As part of its modernization program, NWS plans to shift its field
office structure from 52 Weather Service Forecast Offices and 204
WSOs, to one with 119 WFOs.\7
NWS field offices provide basic weather services such as forecasts,
severe weather warnings, warning preparedness, and--where
applicable--aviation and marine forecasts. Warnings include
"short-fused"--events such as tornadoes, flash floods, and severe
storms--and "long-fused"--events such as gales and heavy snow. NWS
broadcasts forecasts and warnings over the National Oceanic and
Atmospheric Administration's (NOAA) Weather Radio. NWS offices
transmit hourly weather updates and severe weather warnings as they
are issued on hundreds of NOAA Weather Radio stations around the
country. Warning preparedness includes coordinating with local
emergency management, law enforcement agencies, and the media on
notification of and response to severe weather events, and training
volunteer weather observers to collect and report data under a
program commonly called Skywarn. NWS relies heavily on supplemental
data provided by Skywarn volunteers' reports on severe weather
events.
Under NWS' restructuring plan, the Erie WSO is slated for closure and
has been spun down operationally. When fully functioning, this
office's primary role was to provide severe weather warnings to nine
counties in northwestern Pennsylvania, operate an on-site radar, and
take surface-condition weather observations. Under the NWS field
office restructuring, responsibility for Erie's nine counties is
divided among three WFOs: Erie and Crawford counties are served by
the Cleveland WFO; Venango and Forest counties are served by the
Pittsburgh WFO; and Cameron, Elk, McKean, Potter, and Warren counties
are served by the Central Pennsylvania WFO (located at State College,
Pennsylvania).\8 Figures 1 and 2 present maps of the premodernized
and modernized office structures for the northwestern Pennsylvania
area.
Figure 1: Premodernized NWS
Office Structure for
Northwestern Pennsylvania
(See figure in printed
edition.)
Figure 2: Modernized NWS
Office Structure for
Northwestern Pennsylvania
(See figure in printed
edition.)
Under the field office restructuring, the three offices assuming
coverage responsibility for Erie's nine counties have been in the
process of installing new systems and equipment, such as new radars,
and training staff in using the new technologies. In addition, each
office taking on part of Erie's former responsibilities communicated
modernization and restructuring changes with the newly-assumed
counties' emergency response community, volunteer weather observers,
the media, and the public. Once sufficient systems and staff were in
place, the three WFOs--Cleveland, Pittsburgh, and Central
Pennsylvania--began assuming responsibility for their respective
counties. Erie gradually phased out its routine radar operation; it
was responsible for augmenting ASOS until October 1996 when FAA took
over responsibility for this function.
Two other NWS changes affected the Erie area, but were not part of
the spin-down or required for consideration in making an office
closure certification; these changes affected the number and type of
forecasts issued and the area covered by the forecasts. First, in
both the premodernized and modernized environments, the 2-day
forecast is broken into four 12-hour periods. However, with access
to improved, real-time data from new technology--primarily the new
radars implemented as part of the modernization--NWS in 1994 added a
short-term forecast, called the Nowcast, which is a 6-hour forecast.
The second change NWS implemented during modernization was a
reduction in the area covered by its zone forecast. Before
modernization, forecast zones (i.e., the areas for which a particular
forecast was issued) could include several counties as well as
specific localized forecasts for high-population areas. In October
1993, NWS reduced the size of its zones to single counties to allow
forecasters to take advantage of improved data and make more specific
forecasts and warnings. Because of this ability to be more specific,
most NWS areas discontinued the localized forecasts for
high-population areas.
The Weather Service Modernization Act\9 requires that before any
office may be closed, the Secretary of Commerce must certify to the
Congress that closing the field office will not degrade service to
the affected area. This certification must include (1) a description
of local weather characteristics and weather-related concerns that
affect the weather services provided within the service area, (2) a
detailed comparison of the services provided within the service area
and the services to be provided after such action, (3) a description
of recent or expected modernization of NWS operations that will
enhance services in the area, (4) identification of areas within a
state that will not receive coverage (at an elevation of 10,000 feet
or below) by the modernized radar network, (5) evidence, based upon a
demonstration of modernized NWS operations, used to conclude that
services will not be degraded from such action, and (6) any report of
the Modernization Transition Committee\10 that evaluates the proposed
certification.
In response to concerns from members of the Congress, the Department
of Commerce agreed to take several steps to identify community
concerns regarding modernization changes, such as office closures,
and study the potential for degradation of service. First, the
Department published a notice in the Federal Register in November
1994, requesting comments on service areas where it was believed that
premodernized weather services may be degraded with planned
modernization changes. Next, the Department contracted with NRC to
conduct an independent scientific assessment of proposed modernized
radar coverage and consolidation of field offices in terms of the no
degradation of service requirement. In addition, NRC established
criteria for identifying service areas where the elimination of older
radars could degrade services. Finally, the Secretary of Commerce
applied the NRC criteria to identified areas of concern to determine
whether a degradation of service is likely to occur. The resulting
report, Secretary's Report to Congress on Adequacy of NEXRAD Coverage
and Degradation of Weather Services Under National Weather Service
Modernization for 32 Areas of Concern, was issued in October 1995.
--------------------
\7 This discussion of field offices does not include river forecast
centers because the role of these offices was not changed by the
modernization and restructuring.
\8 The Central Pennsylvania office is not fully staffed and,
therefore, has not yet accepted its full responsibilities for the
five former Erie counties. Long-fused forecasting services for these
counties are still provided by the Pittsburgh office. NWS plans to
fully staff this office in fiscal year 1998.
\9 Public Law 102-567, 106 Stat. 4303 (1992).
\10 The Weather Service Modernization Act established this committee
with representatives from NWS, FAA, the Department of Defense, the
Federal Emergency Management Agency, civil defense and public safety
organizations, news media, labor organizations, meteorological
experts, and private sector users of weather information.
ERIE SPIN-DOWN BEGAN PRIOR TO
INITIATION OF COMMERCE REVIEW
------------------------------------------------------------ Letter :4
NWS started spinning down the Erie WSO by transferring warning
responsibilities to the three assuming WFOs in August 1994 before the
Department of Commerce began its review of areas of concern.
However, Erie community members raised questions in June 1994,
several months before Erie was identified as one of the areas of
concern through the Federal Register process. NWS continued with its
plans to spin down the office because officials believed they would
be providing the best service to the area by relying on modernized
radars in other offices. Erie continued surface observations and
radar operations until October 1996 and March 1997, respectively.
The starting point for the Department of Commerce study of areas of
concern was the November 1994 Federal Register announcement
soliciting concerns about NWS modernization and restructuring plans.
In February 1995, Erie was identified as 1 of 32 areas of concern.\11
The Department of Commerce reviewed the 32 areas between June and
August 1995, and issued its report in October 1995. The report
concluded that with the exception of lake-effect snow, the assuming
WFOs will be able to detect severe weather phenomena over
northwestern Pennsylvania. In addition, the report recommended that
NWS (1) compare the adequacy of the assuming WFOs' new radars and
other data sources with Erie's old radar in identifying lake-effect
snow over a 2-year period and (2) transmit data from Erie's radar to
nearby WFOs to support the lake-effect snow study and facilitate the
continued spin-down of the Erie office.
--------------------
\11 Residents of northwestern Pennsylvania raised concerns that the
Erie closure could result in a degradation of service. A list of all
areas of concern was published in the Federal Register on February
23, 1995.
TYPES OF NWS SERVICES PROVIDED
BEFORE AND AFTER SPIN-DOWN ARE
GENERALLY THE SAME, BUT
CONCERNS EXIST REGARDING NWS'
ABILITY TO SERVE DISTANT AREAS
------------------------------------------------------------ Letter :5
The three weather offices that assumed responsibility for the
counties formerly served by the Erie WSO provide generally the same
types of services that the Erie office had provided, with the
exception of the general public's local or toll-free telephone access
to NWS personnel. The general public in the nine counties must now
call long-distance to contact the Cleveland, Central Pennsylvania,
and Pittsburgh WFOs.
Services for Erie and Crawford counties are now provided entirely by
the Cleveland WFO. There are few changes to the services that were
provided by the Erie WSO. The primary changes are the discontinuance
of the localized forecast for the city of Erie and the addition of
the Nowcast. As noted before, localized forecasts were discontinued
because of changes in the size and detail of zone forecasts. Another
significant change is the transfer of ASOS augmentation to FAA. This
relieves NWS of maintaining staff on-site to take observations.
Table 1 presents a detailed comparison of the services provided to
Erie and Crawford counties before and after spin-down.
Table 1
Services Provided to Erie and Crawford
Counties Before and After Spin-Down
Previously
provided by Now provided by Date of change
Service ------------------ ------------------ --------------------
Short-fused Erie Cleveland 8/94
warnings
(including
warnings for
adjacent coastal
waters)
Long-fused Pittsburgh Cleveland 10/95
warnings
Forecasts Pittsburgh Cleveland 10/95
(including
individual county
forecasts and
Nowcasts)
Erie modified Local forecast 9/94
Pittsburgh's first discontinued
period forecast
(hours 0-12) and
issued as a local
forecast for the
city of Erie
Open-lake waters Cleveland Cleveland N/A
and near-shore
forecasts,
warnings, and
advisories
Bay report Not an official Cleveland N/A
(current wind and NWS service before
wave conditions) modernization
Aviation forecast Pittsburgh Cleveland 10/95
for Erie
International
Airport
Warning Erie Cleveland 8/94
preparedness
Surface Erie ASOS augmentation 10/96
observations turned over to FAA
NOAA Weather Radio Erie Cleveland 8/94
Climatological Erie Cleveland 10/95
services (daily
and monthly
messages)
--------------------------------------------------------------------------------
The Pittsburgh WFO now provides all services to Venango and Forest
counties with the exception of issuing NOAA weather radio reports and
updates. Changes in services to these counties are minimal as
Pittsburgh was already providing many services to these areas. The
only significant change is the addition of the short-term
forecast--the Nowcast--which was not provided in premodernization.
Table 2 presents a detailed comparison of services provided before
and after spin-down.
Table 2
Services Provided to Venango and Forest
Counties Before and After Spin-Down
Previously
Service provided by Now provided by Date of change
------------------ ------------------ ------------------ --------------------
Short-fused Erie Pittsburgh 8/94
warnings
Long-fused Pittsburgh Pittsburgh N/A
warnings
Forecasts Pittsburgh Pittsburgh N/A
(including
individual county
forecasts and
Nowcasts)
Warning Erie Pittsburgh 8/94
preparedness
NOAA Weather Radio Erie--however, Cleveland 8/94
existing (providing same
transmitters did coverage as Erie)
not serve all
areas in these
counties
Climatological Erie Pittsburgh 10/95
services (daily
and monthly
messages)
--------------------------------------------------------------------------------
Services for Cameron, Elk, McKean, Potter, and Warren counties are
now provided mostly by the Central Pennsylvania WFO. Since this
office is not yet fully staffed, forecasting and long-fused warning
services are still provided by Pittsburgh. Again, with the exception
of the Nowcast, no major changes have occurred for these counties.
Since many of these counties are mountainous, NOAA Weather Radio
service does not reach all areas. NWS believes service will be
improved when additional transmitters are installed in fiscal year
1998. The Central Pennsylvania and Pittsburgh WFOs will program
these transmitters. Table 3 presents a detailed comparison of
services provided before and after spin-down.
Table 3
Services Provided to Cameron, Elk,
McKean, Potter, and Warren Counties
Before and After Spin-Down
Previously
provided by Now provided by Date of change
Service ------------------ ------------------ --------------------
Short-fused Erie Central 8/94
warnings Pennsylvania
Long-fused Pittsburgh Pittsburgh (will N/A
warnings be provided by
Central
Pennsylvania once
office is fully
staffed)
Forecasts Pittsburgh Pittsburgh N/A
provides
individual county
forecasts; will be
provided by
Central
Pennsylvania once
office is fully
staffed
Central 5/94
Pennsylvania
provides Nowcasts
Warning Erie Central 8/94
preparedness Pennsylvania
NOAA Weather Radio Erie, Pittsburgh, Central 8/94
and Williamsport Pennsylvania and
WSO--however, Cleveland
existing (providing same
transmitters did coverage as
not serve all before)
areas in these
counties
Climatological Erie Central 10/95
services (daily Pennsylvania
and monthly
messages)
--------------------------------------------------------------------------------
CONCERNS RAISED ABOUT
SERVICES TO ERIE AND
CRAWFORD COUNTIES AND NWS
RESPONSES
---------------------------------------------------------- Letter :5.1
Many concerns have been raised about the specific services being
provided by NWS as well as the quality of the service provided. Most
concerns had been brought to NWS' attention and NWS provided
responses to them. Other concerns brought to our attention either
had not been reported to NWS or NWS had not officially responded. We
discussed these concerns with NWS officials and received their
responses. The most common concern--voiced by almost every
individual we spoke with--was with the ability of distant radars to
detect all types of weather phenomena. Table 4 presents concerns
raised by users in Erie and Crawford counties and NWS' responses.
Table 4
Concerns Raised About Services to Erie
and Crawford Counties and NWS Responses
Concern NWS response
--------------------------------------- ---------------------------------------
Cleveland WFO too far away to be able Modernized radars are very effective
to forecast weather and issue severe even at long ranges for most phenomena
weather warnings accurately and timely. and provide improved service over older
radars; verification statistics support
this statement for northwestern
Pennsylvania.
Gap in radar coverage will affect NRC and Commerce studies support this
ability to detect lake-effect snow. concern; NWS is completing a lake-
effect snow study to determine NWS'
ability to detect this phenomenon over
northwestern Pennsylvania.
Verification statistics for the Erie Statistics show the accuracy of
area show warnings were more accurate warnings for the nine-county Erie area
when the Erie WSO was issuing warnings. have improved overall.\a
Cleveland staff are not familiar with Terrain and weather are similar to that
terrain and weather experienced in of northeastern Ohio, which are
northwestern Pennsylvania. familiar to staff; several staff
members have visited the area.
Lake-effect snow study data collection Data collection did change during the
was inconsistent--too few data points 3-year study as NWS attempted to enlist
and not always scientifically additional volunteers--the number of
collected. volunteers for Erie and Crawford
counties changed each year during the
3-year study from 15, 13, to 22;
volunteers were trained by NWS
personnel in proper data collection
procedures.
Erie WSO is providing no services, Erie WSO is not closed because
therefore the office should be operation of the Erie radar was
considered closed; however, NWS has not required for the lake-effect snow
yet completed a "no degradation of study; NWS is awaiting the results of
service" certification. the study to determine if degradation
exists and, if so, how to address the
problem.
Public telephone service was The Erie office does not have
discontinued in the Erie office in modernized equipment and therefore
spring 1996; the community must now cannot provide the best weather
call Cleveland for information. information to the public; NWS wants
communities to begin relying on their
new weather offices.
There is no public toll-free telephone Cleveland offers toll-free telephone
number for Cleveland. numbers to emergency management and
Skywarn; it also offered free telephone
access to the public until February
1997, when budget cuts dictated that
this service be eliminated.
The public telephone number for The public number is available during
Cleveland is not answered 24 hours a regular business hours--8:30 a.m. to
day. 4:30 p.m.; 24-hour service is available
to emergency management, state, county,
and municipal officials, and Skywarn
volunteers.
There is no forecast for Presque Isle Erie WSO never issued a separate Bay
Bay; the near-shore forecast does not forecast; the near-shore forecast
specifically address the Bay. includes the Bay, which generally
experiences less severe conditions than
other waters in the near-shore
forecast.
Wind reports and near-shore forecasts Three additional wind sensors were
are inadequate. installed along the shore to provide
better information.
Sometimes there are missing wind sensor The missing reports are usually from
reports. the two sensors that are read by state
officials who may not take observations
if their workload does not permit it;
the one automated sensor will always
provide data unless the equipment is
inoperable.
Proposed marine prediction unit cut in No changes yet; if a change is made,
Cleveland will adversely affect Lake however, Cleveland will still issue
Erie service. near-shore forecasts--the marine
prediction unit is responsible for ice
and wind reports used primarily by
commercial carriers.
Fear of untimely service of NOAA No problems reported; Cleveland focuses
Weather Radio. priority on quick service to
northwestern Pennsylvania.
ASOS cannot adequately replace human ASOS was not designed to completely
observations of all critical weather replace human observers and requires
conditions, such as tornadoes, blowing augmentation for certain observations;
snow, and clouds above 12,000 feet. this is being provided by FAA for the
ASOS unit at the Erie International
Airport.
Reliance on ASOS will interrupt the The Erie ASOS is augmented by FAA for
historical climate record because it critical weather observations with the
cannot report on all critical weather exception of snow depth--this is
conditions. provided by volunteer observers for
northwestern Pennsylvania.
Outreach on modernization and Cleveland, Pittsburgh, Central
restructuring issues was insufficient. Pennsylvania, region headquarters, and
Erie personnel communicated with users
and the community in over 100
instances, such as notification
letters, briefings, and Skywarn
training sessions.
NOAA Weather Radio updates are issued Erie only had to issue updates for one
later than when issued by Erie. station and therefore issued updates
just a few minutes after the hour; with
new responsibilities, Cleveland has to
issue updates for four stations and, as
a result, Erie's updates were issued
later than normal; in response to
concerns, Cleveland has begun issuing
the Erie updates first.
Too few staff per shift will result in Cleveland is following NWS policy on
some areas getting degraded coverage if the number of staff; during severe
multiple severe events occur at the weather events staff will be
same time. supplemented with overtime employees,
as needed.
Some severe weather events have been Weather prediction and severe weather
missed and some forecasts have been warning are never 100 percent accurate;
inaccurate. some events inevitably are missed.
Specifically:
A tornado in June 1994 was not Erie WSO still had authority for
detected on Cleveland's radar and a issuing warnings; Cleveland's radar
warning was not issued until after showed severe storm activity and staff
touch-down. were talking with Erie staff to
determine whether a tornado was
possible.
A funnel cloud in May 1996 was not Cleveland issued a tornado warning 2
detected by ASOS. hours prior to detection; the funnel
cloud was detected by ASOS
augmentation.
Severe flooding in September 1996 was The flood was a once-in-a-100 years
not predicted and Cleveland radar could event. Intense rainfall was generated
not see the intense rainfall. by very low-topped clouds, which is an
unusual cause for rainfall of this
amount. Cleveland radar did not see
this event because the weather pattern
was so low and the Erie radar could not
detect the intensity of the rainfall.
However, after heavy rainfall started,
Cleveland used rainfall and flood
reports from volunteers to issue
subsequent warnings.
--------------------------------------------------------------------------------
\a See appendix I for NWS' verification statistics for this area.
CONCERNS RAISED ABOUT
SERVICES TO CAMERON, ELK,
FOREST, MCKEAN, POTTER,
VENANGO, AND WARREN COUNTIES
AND NWS RESPONSES
---------------------------------------------------------- Letter :5.2
The primary concern voiced from five of the seven counties now served
by the Central Pennsylvania and Pittsburgh WFOs was the ability of
distant radars to provide adequate coverage for severe weather
phenomena in order to issue accurate and timely forecasts and
warnings. Some users in counties at the fringes of radar coverage
questioned NWS' ability to track approaching severe weather outside
the range of an office's radar. NWS' responses to these concerns
were to assure county officials and residents that the new radars and
other components of the modernization, such as satellites and
improved weather models, would enable NWS to provide better service
to their areas. Furthermore, WFOs can access radar data from nearby
WFOs. For example, if a severe storm was moving eastward into
northwestern Pennsylvania, Central Pennsylvania and Pittsburgh staff
would likely access data from Cleveland's radar to help determine the
path and intensity of the event.
One individual expressed concern that during severe weather events,
there may not be sufficient staff to operate the amateur radio
equipment, which is used to communicate with Skywarn volunteers.
According to NWS, there are licensed amateur radio operators on
staff. However, if licensed staff are not available during severe
events, NWS can call on volunteers to help operate the equipment.
These concerns seemed to have been allayed as most officials told us
that service provided by the new offices is at least equal to the
service provided before modernization.
CONCERNS ABOUT SERVICES AT THE
ERIE AIRPORT AND TIMELINESS OF
LAKE ERIE SMALL-CRAFT
ADVISORIES
------------------------------------------------------------ Letter :6
A few concerns have been raised regarding weather services provided
at the Erie International Airport and the timeliness of small-craft
advisories for Lake Erie. The most commonly cited concern was with
ASOS, which has been the subject of much scrutiny since its
nationwide deployment. We reported on several ASOS issues in
1995,\12 such as specific sensor problems and the system's difficulty
reporting actual, prevailing conditions in rapidly changing or patchy
weather conditions. NWS has implemented modifications to address
sensor problems and, in some places, including Erie, added sensors to
better report representative observations. In addition, since ASOS
does not replace all human observations, human observers must
continue to take manual observations at airports such as Erie to
supplement the system (this process is called augmentation) and
correct the system when it is not accurately reporting current
conditions.
Under an NWS/FAA interagency agreement, FAA accepted augmentation
responsibility for the Erie ASOS in October 1996. At that point, NWS
weather observers were discontinued at Erie and air traffic
controllers became responsible for augmenting ASOS observations and
correcting the system when it reported inaccurate conditions.
Concerns surround the issue of whether this ASOS augmentation
responsibility is too much for air traffic controllers. FAA
recognizes these concerns and has sponsored an independent study of
the impact of ASOS augmentation. According to the manager of FAA's
Aviation Weather Requirements Division, a report is expected in the
fall of 1997. Table 5 presents specific safety concerns raised and
NWS responses.
Table 5
Concerns Raised About Safety at Erie
International Airport and Timeliness of
Small-Craft Advisories,
and NWS Responses
Concern NWS response
--------------------------------------- ---------------------------------------
FAA controllers must augment ASOS; this FAA agreed to assume ASOS augmentation
places too much work on controllers at responsibilities; in response to
the risk of safety. concerns from controllers, FAA has
sponsored a study of the impact of ASOS
augmentation.
ASOS is unrepresentative of prevailing A joint NWS/FAA/aviation industry study
conditions; this can have safety found that ASOS is representative 98
implications for aircraft approach and percent of the time; an additional
landing. sensor was installed apart from the
ASOS sensor group to identify when
visibility conditions are different
from the official ASOS observation
(i.e., to identify when the official
ASOS observation may be
unrepresentative of prevailing
conditions).
Terminal forecasts are no longer sent Cleveland is issuing terminal forecasts
directly to the Erie airport tower. as required and disseminating them to
FAA; the Erie WSO arrangement of
sending forecasts directly to the
airport tower was a favor.
Some severe weather on Presque Isle Bay Weather prediction and severe weather
and Lake Erie have occurred without warning are not 100 percent accurate;
warnings. some events inevitably are missed.
Specifically:
A high school rowing team was Cleveland office records show that
practicing on Presque Isle Bay when NWS first issued a small-craft advisory
high winds capsized rowing shells; no the night before the incident and
severe weather warnings were issued. upgraded its advisory to gale warnings
at 3:48 a.m. on the day of the
incident; such warnings and advisories
are included in NOAA Weather Radio
updates and sent to local TV and radio
stations via regular NWS dissemination
avenues.
Several waterspouts have occurred Waterspouts are not detectable with
without warning. either the old or new radars although
NWS will issue warnings when conditions
look favorable for waterspout activity.
--------------------------------------------------------------------------------
--------------------
\12 Weather Forecasting: Unmet Needs and Unknown Costs Warrant
Reassessment of Observing System Plans (GAO/AIMD-95-81, April 21,
1995).
NO EVIDENCE OF SERVICE
DEGRADATION, BUT DETECTION OF
LAKE-EFFECT SNOW REMAINS A
CONCERN
------------------------------------------------------------ Letter :7
There are several sources of evidence that address whether a
degradation of service has occurred in the Erie area. NWS'
statistical verification program collects performance data on the
issuance of forecasts and warnings and provides information necessary
to compare "premodernized" and "modernized" performance. Overall,
data for the former nine-county Erie WSO area show an improvement in
service under the three WFOs.
Studies by NRC and the Department of Commerce analyzed the ability of
the new radars and other components of the modernization to detect
certain weather phenomena and assessed the potential for degradation
of weather services in the Erie area. NRC concluded that the ability
to detect three severe weather phenomena, including lake-effect snow,
was questionable. The Department of Commerce's study expanded on
NRC's work and concluded that lake-effect snow was the only phenomena
that remained a concern. NWS is completing a 3-year study of its
ability to detect and predict lake-effect snow in the Great Lakes
area, which includes northwestern Pennsylvania.
ACCURACY AND TIMELINESS OF
WARNINGS AND FORECASTS SHOW
OVERALL IMPROVEMENT
---------------------------------------------------------- Letter :7.1
Since the 1980s, NWS has assessed the accuracy and timeliness of its
severe weather warnings and public and aviation forecasts through a
statistical verification program. The verification process includes
determining the accuracy of the forecast elements of maximum and
minimum temperature and probability of precipitation. Several
elements of the aviation forecasts are likewise verified. Severe
weather warnings are verified by determining whether an event for
which a warning was issued occurred. The elements calculated for
warning verification are probability of detection (i.e., NWS' ability
to detect weather events--the higher the probability, the better the
performance), false alarm rate, and lead time. If a warning was
issued but a severe weather event did not occur, a higher false alarm
rate results. If a severe weather event occurred without a warning,
the probability of detection goes down.
Warning and forecast verification statistics historically have been
used to help weather office managers determine trends in performance
and identify areas needing improvement. With modernization, the
statistics are included in the certification package as support
either for or against a determination of degradation of service. NWS
officials stressed, however, that verification statistics are not the
most important component of the no-degradation assessment. Rather,
they said, they rely most heavily on feedback from users to determine
satisfaction with the level of service being provided and whether
degradation has occurred.
The verification statistics for the nine former Erie office counties
show an overall improvement to the area in warning service. Appendix
I presents the warning verification data for the nine-county area.
The statistics also show slight improvement for public forecast
service. The aviation forecast verification statistics show a
negligible decline from .33 to .32, on a scale from 0 to 1 with 1
being the best performance.
NWS officials cautioned that there are limitations to the
verification program and resulting data. For example, since the
number and type of weather events vary from year to year, it is
impossible to directly compare performance from one year to another.
In addition, it is more difficult to verify events in sparsely
populated areas. Finally, NWS officials acknowledged that severe
weather warning verification procedures vary across offices.
NRC CONCLUDED THAT NEW
RADARS MAY MISS THREE KEY
WEATHER PHENOMENA
---------------------------------------------------------- Letter :7.2
In August 1994, the Department of Commerce contracted with NRC to
study NWS' modernized radar network coverage and identify any gaps
that could result in a degradation of weather service. In addition,
NRC was to develop criteria for the Department to use in determining
the potential for degradation of service in those areas of concern
identified through the public comment process.
In June 1995, NRC issued its report, Toward a New National Weather
Service: Assessment of NEXRAD Coverage and Associated Weather
Services. Overall, NRC concluded that weather services on a national
basis would be improved substantially under the new radar network.
For example, compared with the old radar network, the modernized
radar network will cover a much broader area of the contiguous United
States and provide greater coverage for detecting specific severe
weather phenomena, such as supercells, mini-supercells, and
macrobursts.\13 NRC also noted that the new radars are just one
element in a composite weather system that includes satellites,
automated surface observing equipment, wind profilers, improved
numerical forecast models, and cooperative networks of human
observers and spotters.
NRC cautioned, however, that at old radar sites where radar coverage
is to be provided by a new radar some distance away, there is the
potential for degradation in radar-detection coverage capability. In
particular, northwestern Pennsylvania was one such area with degraded
radar coverage for macrobursts, mini-supercells, and lake-effect
snow. NRC recommended NWS study the area to determine whether the
degraded radar coverage would result in a degradation of weather
service. Figure 3 shows the approximate gap in radar coverage for
lake-effect snow over northwestern Pennsylvania.
Figure 3: Approximate Gap in
Radar Coverage for Lake-Effect
Snow
(See figure in printed
edition.)
Note: The shaded counties are
those formerly served by the
Erie WSO. The circles indicate
radar coverage for lake-effect
snow by the WFO indicated.
(See figure in printed
edition.)
Source: National Research
Council, 1995.
(See figure in printed
edition.)
--------------------
\13 A supercell may produce high winds, large hail, and long-lived
tornadoes, and may last several hours. A mini-supercell contains
similar characteristics as a supercell but is significantly smaller.
A macroburst--which is caused by a strong downdraft--is an outburst
of damaging winds on or near the ground over an area greater than 2.5
miles.
THE DEPARTMENT OF COMMERCE
CONCLUDED THAT NEW RADARS
MAY MISS LAKE-EFFECT SNOW
---------------------------------------------------------- Letter :7.3
As agreed with concerned members of the Congress, the Department of
Commerce used NRC's criteria to evaluate the potential for
degradation in the 32 areas identified via the Federal Register
process and assessed the potential for degradation of service for the
radar gaps identified in NRC's report.\14 The Secretary's team
conducted additional research into the capabilities of the new radars
and found that the effective range of detection was greater than
estimated by NRC. Specifically, the team concluded that the new
radars serving the former Erie WSO area would be able to detect
macrobursts and mini-supercells for northwestern Pennsylvania. It
was still clear, however, that the radars could not adequately detect
some lake-effect snow events in the Erie area. Therefore, the
Secretary's team recommended that NWS compare the adequacy of the
assuming WFOs' new radars and other data sources with Erie's old
radar in identifying lake-effect snow over a 2-year period to
determine how well the composite weather system could help detect and
predict lake-effect snow over the area in question. In addition, the
report recommended that NWS keep the Erie radar (an older vintage)
operational until the results of the study were compiled, which was
done.
--------------------
\14 The group that conducted this assessment, referred to as the
"Secretary's Team," worked from June through August 1995. The report
was issued on October 12, 1995.
DEGRADATION OF LAKE-EFFECT
SNOW DETECTION NOT EVIDENT,
BUT SERVICE NOT AS GOOD AS
ELSEWHERE ALONG THE GREAT
LAKES
---------------------------------------------------------- Letter :7.4
NWS began a lake-effect snow study in November 1994, 1 year before
the Secretary's team recommended that a similar assessment be done.
NWS initiated the study to improve its ability to detect and predict
lake-effect snow, as well as in response to concerns raised by
congressional staff and residents of northern Indiana and
northwestern Pennsylvania; these areas were scheduled to lose old
radars and, instead, receive coverage from more distant but
modernized radars. The goal of the study was to find ways of
improving the warning and forecast services associated with
lake-effect snow events. In response to the Secretary's team's
recommendation, however, another goal was added to this study--to
determine whether lake-effect snow detection would be degraded over
northwestern Pennsylvania, if the Erie radar and office were shut
down.
Data on lake-effect snow were collected over the three winter seasons
between 1994 and 1997. While the broad study area included all areas
in New York, Pennsylvania, Ohio, and Indiana that experience
lake-effect snow, a seven-county area was established surrounding
Erie on which more specific analysis would be performed.\15 After
each winter season, a data report was issued by NWS.
These reports conclude that NWS has made significant progress in
improving its ability to detect and forecast lake-effect snow,
however, there are still questions about the level of this service
being provided to northwestern Pennsylvania. For example, NWS'
Eastern Region reported that for about 35 percent of lake-effect snow
events, the composite weather system will be insufficient to
compensate for the degradation in radar coverage over northwestern
Pennsylvania.\16 In addition, this report stated that NWS is not able
to provide detailed, short-term forecasts (Nowcasts) during
lake-effect snow events like it can for other areas that have better
radar coverage. The Eastern Region's report and the director of NWS'
Office of Meteorology point out, however, that this problem does not
constitute a degradation of service because the probability of
detection for lake-effect snow in the seven-county study area has
improved since 1993.
Even though degradation has not occurred, according to the Eastern
Region report and the director, this level of service is still
unacceptable because lake-effect snow is the Erie area's most severe
weather condition and the community does not receive the same level
of service that other lake communities receive. As a result, the
Eastern Region report recommended that a radar be installed to
provide better coverage for this severe weather phenomenon in
northwestern Pennsylvania. The director of the Office of Meteorology
agrees with this recommendation, but points out that since data from
this new radar would be transmitted to existing WFOs, an additional
weather office is not needed in the Erie area.
NWS' final report of the lake-effect snow study is expected this
fall. Any conclusions and recommendations from the lake-effect snow
study will be reviewed by the Secretary's team, which will make
recommendations to the Secretary regarding specific actions to be
taken. Once the results of the lake-effect snow study are finalized
and actions taken to address degradation concerns, if any, NWS
officials told us they will pursue closure certification for the Erie
office.
--------------------
\15 These counties are Erie, Crawford, and Warren in Pennsylvania;
Ashtabula and Trumbull in Ohio; and Chautauqua and Cattaraugus in New
York. This area is covered by radars in the Buffalo, Central
Pennsylvania, Cleveland, and Pittsburgh WFOs.
\16 A Review of the 1996-1997 Lake-Effect Snow Study in the Eastern
Region of the National Weather Service, July 1997.
AGENCY COMMENTS
------------------------------------------------------------ Letter :8
In commenting on a draft of this report, the Department of Commerce
took no exceptions to the information presented and acknowledged that
we had conducted thorough work in researching the issues and
preparing the report. The Department reiterated that, after NOAA
presents the Secretary's team with the results of the lake-effect
snow study, it will review and evaluate the findings, conclusions,
and recommendations and determine the need for a radar in
northwestern Pennsylvania. The Department's written response is
reprinted in appendix II.
---------------------------------------------------------- Letter :8.1
As agreed with your offices, unless you publicly announce the
contents of this report earlier, we will not distribute it until 10
days from the date of this letter. At that time we will send copies
to the Ranking Minority Member, House Committee on Science, and the
Chairmen and Ranking Minority Members of the Senate Committee on
Commerce, Science, and Transportation; House and Senate Committees on
Appropriations; House Committee on Government Reform and Oversight;
and Senate Committee on Governmental Affairs; and to the Director,
Office of Management and Budget. We are also sending copies to
Senators Arlen Specter and Rick Santorum; Congressman John Peterson;
the Secretary of Commerce; the Administrator, National Oceanic and
Atmospheric Administration; and the Acting Director of the National
Weather Service. Copies will be made available to others upon
request.
Please contact me at (202) 512-6408 if you or your staffs have any
questions concerning this report. I can also be reached by e-mail at
[email protected]. Major contributors to this report are
listed in appendix III.
Joel C. Willemssen
Director, Information Resources Management
WARNING VERIFICATION DATA FOR
ERIE'S NINE-COUNTY AREA
=========================================================== Appendix I
Premodernized Modernized
Tornadoes \a \b
------------------------------------------- ------------- ----------
Number of events 4 4
Probability of detection\c 0.00 0.75
False alarm rate\d 1.00 0.85
Lead-time (minutes) N/A 14.3
----------------------------------------------------------------------
Premodernized Modernized
Severe local storms \a \b
------------------------------------------- ------------- ----------
Number of events 379 147
Probability of detection\c 0.79 0.86
False alarm rate\d 0.37 0.48
Lead-time (minutes) 21.7 23.5
----------------------------------------------------------------------
Premodernized Modernized
Flash floods \a \b
------------------------------------------- ------------- ----------
Number of events 72 85
Probability of detection\c 0.57 0.81
False alarm rate\d 0.67 0.46
Lead-time (minutes) 28.9 45.5
----------------------------------------------------------------------
Note: NWS officials cautioned that there are limitations to the
verification program and resulting data. For example, since the
number and type of weather events vary from year to year, it is
impossible to directly compare performance from one year to another.
In addition, it is more difficult to verify events in sparsely
populated areas. Finally, NWS officials acknowledged that severe
weather warning verification procedures vary across offices.
\a The premodernized period is January 1, 1986, through July 31,
1994.
\b The modernized period is August 1, 1994, through December 31,
1996.
\c Probability of detection is measured on a scale of 0 to 1 with 0
representing no detection of severe weather events and 1 representing
complete detection of all severe weather events.
\d The false alarm rate is measured on a scale of 0 to 1 with 0
representing no false alarms issued and 1 representing all warnings
issued being false alarms.
Source: National Weather Service.
(See figure in printed edition.)Appendix II
COMMENTS FROM THE DEPARTMENT OF
COMMERCE
=========================================================== Appendix I
MAJOR CONTRIBUTORS TO THIS REPORT
========================================================= Appendix III
ACCOUNTING AND INFORMATION
MANAGEMENT DIVISION, WASHINGTON,
D.C.
Keith A. Rhodes, Technical Director
Mark E. Heatwole, Assistant Director
Patricia J. Macauley, Information Systems Analyst-in-Charge
J. Michael Resser, Business Process Analyst
Michael P. Fruitman, Communications Analyst
*** End of document. ***