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577
NOUS41 KWBC 031845
PNSWSH
SERVICE CHANGE NOTICE 04-35
NATIONAL WEATHER SERVICE HEADQUARTERS WASHINGTON DC
240 PM EDT THU JUN 02 2004
TO: FAMILY OF SERVICES /FOS/ SUBSCRIBERS...NOAA
WEATHER WIRE SERVICE /NWWS/SUBSCRIBERS...
EMERGENCY MANAGERS WEATHER INFORMATION NETWORK
/EMWIN/ SUBSCRIBERS...NOAAPORT SUBSCRIBERS...
OTHER NATIONAL WEATHER SERVICE /NWS/ CUSTOMERS
AND PARTNERS...AND NWS EMPLOYEES
FROM: GLENN AUSTIN
CHIEF...HYDROLOGIC SERVICES DIVISION
SUBJECT:CHANGE TO FORMAT OF EXCESSIVE PRECIPITATION
GRAPHIC...EFFECTIVE OCTOBER 5 2004
ON TUESDAY...OCTOBER 5 2004...AT 1500 COORDINATED UNIVERSAL
TIME /UTC/...THE NATIONAL WEATHER SERVICE WILL CHANGE THE
FORMAT OF THE EXCESSIVE PRECIPITATION FORECAST ISSUED BY THE
HYDROMETEOROLOGICAL PREDICTION CENTER /HPC/.
THIS PRODUCT USES WORLD METEOROLOGICAL ORGANIZATION /WMO/
HEADER...PE1745 KWBC...AND AWIPS IDENTIFIER RBG94E.
THE EXCESSIVE PRECIPITATION FORECAST WILL BE PROBABILISTIC
IN NATURE...SIMILAR TO THE CURRENT SEVERE CONVECTIVE STORM
FORECASTS ISSUED BY THE STORM PREDICTION CENTER /SPC/.
THE NEW GRAPHIC WILL DISPLAY AREAS WHERE THE PROBABILITY OF
PRECIPITATION EXCEEDING FLASH FLOOD GUIDANCE IS SLIGHT
/SLGT/... DEFINED AS THREAT IN THE RANGE 20 PERCENT TO LESS
THAN 40 PERCENT...MODERATE /MDT/ DEFINED AS THREAT FROM 40
PERCENT TO LESS THAN 70 PERCENT...AND HIGH DEFINED AS THREAT
70 PERCENT OR GREATER. THE AREAS OF THREAT WILL BE
DELINEATED BY CLOSED CONTOURS OR TO THE RIGHT OF A LINE. THE
DIRECTION OF THE LINE WILL BE INDICATED BY AN ARROWHEAD AT
THE END OF THE LINE.
AREAS WHERE THE PRECIPITATION IS EXPECTED TO EXCEED 5 INCHES
WILL ALSO BE INDICATED.
THE DEFINITION OF EXCEEDING FLASH FLOOD GUIDANCE IS BROAD.
FLASH FLOOD GUIDANCE IS ISSUED BY SEVERAL RIVER FORECAST
CENTERS WITH VALUES ASSOCIATED WITH 1 HOUR...3 HOUR...
6 HOUR... AND IN SOME CASES. . .12 AND 24 HOURS. THE HPC
FORECASTER IS TASKED WITH MAKING A DETERMINATION OF THE
THREAT PRECIPITATION WILL EXCEED ANY OF THE PREDETERMINED
FLASH FLOOD GUIDANCE VALUES ASSOCIATED WITH THE SPECIFIC
TIME INTERVAL IN THE VALID TIME PERIOD OF THE FORECAST. IT
IS NOT INTENDED AS A SPECIFIC FORECAST OF FLASH FLOODING BUT
RATHER AS A PROBABILISTIC INDICATOR OF RAINFALL AMOUNTS
EXCEEDING FLASH FLOOD GUIDANCE OVER AN AREA.
THE EXCESSIVE PRECIPITATION FORECAST IS ISSUED FOUR TIMES
DAILY. THE VALID TIME PERIOD IS 24 HOURS FOR THE PRIMARY
ISSUANCES AT 0615 UTC AND 1815 UTC...AND FOR THE REMAINDER
OF THE INITIAL PERIOD ON THE UPDATE CYCLES AT 1415 UTC AND
0215 UTC.
THE ASSOCIATED TEXT PRODUCT WILL BE WRITTEN IN A MANNER
CONSISTENT WITH THE GRAPHIC. THE TEXT PRODUCT IS LABELED
EXCESSIVE RAINFALL DISCUSSION...WMO HEADER FOUS30
KWBC...AWIPS ID QPFERD.
THE EXCESSIVE PRECIPITATION FORECAST IS PREPARED BY THE
HYDROMETEOROLOGICAL PREDICTION CENTER /HPC/ IN CAMP SPRINGS
MARYLAND. THE DOMAIN OF THE PRODUCT ENCOMPASSES THE 48
CONTIGUOUS STATES. IN ADDITION...THE HPC DISSEMINATES THIS
PRODUCT AND RELATED INFORMATION ON THE INTERNET. THE URL
ADDRESS AVAILABLE OCTOBER 5 IS AS FOLLOWS /USE LOWER CASE
LETTERS/:
HTTP://WWW.HPC.NCEP.NOAA.GOV/WW.SHTML
IF YOU HAVE ANY QUESTIONS ABOUT THE HPC EXCESSIVE
PRECIPITATION PRODUCT SUITE...PLEASE CONTACT
KEVIN MCCARTHY
DEPUTY DIRECTOR
NCEP HPC
CAMP SPRINGS MD
PHONE: 301-763-8000 X7304
EMAIL: KEVIN.MCCARTHY@xxxxxxxx
-OR-
ROBERT KELLY
CHIEF
NCEP/HPC FORECAST OPERATIONS BRANCH
CAMP SPRINGS MD
PHONE: 301-763-8000 X7306
EMAIL: ROBERT.KELLY@xxxxxxxx
THIS NOTICE AND OTHER NWS SERVICE CHANGE NOTICES ARE
AVAILABLE AT /USE LOWER CASE LETTERS/:
HTTP://WWW.NWS.NOAA.GOV/OM/NOTIF.HTM
$$
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