Public Information Statement

NOUS41 KWBC 242007
PNSWSH

SERVICE CHANGE NOTICE 09-15
NATIONAL WEATHER SERVICE HEADQUARTERS WASHINGTON DC
310 PM EST TUE FEB 24 2009

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:       THERESE Z. PIERCE
            CHIEF...MARINE AND COASTAL SERVICES BRANCH

SUBJECT:    CHANGES TO STORM SURGE INFORMATION IN TROPICAL
            CYCLONE PUBLIC ADVISORIES FROM THE NATIONAL
            HURRICANE CENTER: EFFECTIVE MAY 15 2009 

REFERENCE:  SERVICE CHANGE NOTICE 09-14 ISSUED FEB 24 2009

STARTING IN 2009...IN AN EFFORT TO ENSURE STORM SURGE FORECASTS 
ARE FULLY UNDERSTOOD BY THE WIDEST POSSIBLE AUDIENCE...THE 
NATIONAL HURRICANE CENTER /NHC/ WILL CHANGE THE WORDING IN THE 
PUBLIC ADVISORY TEXT PRODUCTS TO REFERENCE STORM SURGE OR STORM 
TIDE IN TERMS OF HEIGHT ABOVE GROUND LEVEL. 

STORM SURGE REFERS TO THE ABNORMAL RISE IN SEA LEVEL
ACCOMPANYING A HURRICANE...THE DIFFERENCE BETWEEN THE OBSERVED
LEVEL OF THE SEA SURFACE AND THE LEVEL THAT WOULD HAVE OCCURRED
IN THE ABSENCE OF THE CYCLONE.  

STORM TIDE IS THE ACTUAL LEVEL OF SEA WATER RESULTING FROM THE
ASTRONOMIC TIDE COMBINED WITH THE STORM SURGE.  STORM TIDE IS OF 
PARTICULAR IMPORTANCE IN THE NORTHERN LATITUDES...WHERE 
THERE IS A GREATER DIFFERENCE IN HEIGHTS BETWEEN HIGH AND LOW 
TIDE LEVELS...AND WHEN A STORM IS EXPECTED TO LANDFALL NEAR THE 
TIMES OF ASTRONOMICAL HIGH TIDE.

BEGINNNING IN 2009...NHC PUBLIC ADVISORY PRODUCTS /TCP/S WILL 
PROVIDE THE FOLLOWING POSSIBLE STATEMENTS ON COASTAL FLOODING
ASSOCIATED WITH TROPICAL CYCLONES:

EXAMPLE 1
STORM SURGE WILL RAISE WATER LEVELS BY AS MUCH AS NN /FOR 
EXAMPLE 15/ FEET ABOVE GROUND LEVEL ALONG THE COAST...WITH LARGE 
AND DANGEROUS BATTERING WAVES...NEAR AND TO THE ZZZZ /DIRECTION 
FOR EXAMPLE EAST/ OF WHERE THE CENTER MAKES LANDFALL.  THE SURGE 
COULD PENETRATE AS FAR INLAND AS ABOUT NN /FOR EXAMPLE 30/ MILES 
FROM THE SHORE WITH DEPTH GENERALLY DECREASING AS THE WATER 
MOVES INLAND.

EXAMPLE 2
STORM TIDE WILL RAISE WATER LEVELS BY AS MUCH AS NN /FOR EXAMPLE 
18/ FEET ABOVE GROUND LEVEL ALONG THE COAST...WITH LARGE AND 
DANGEROUS BATTERING WAVES...NEAR AND TO THE ZZZZ /DIRECTION FOR 
EXAMPLE EAST/ OF WHERE THE CENTER MAKES LANDFALL.  STORM TIDE 
COULD PENETRATE AS FAR INLAND AS ABOUT NN /FOR EXAMPLE 30/ MILES 
FROM THE SHORE WITH DEPTH GENERALLY DECREASING AS THE WATER 
MOVES INLAND.

PLEASE SEE SERVICE CHANGE NOTICE 09-14...ISSUED ON FEB 24 
2009...FOR FORMAT CHANGES TO TROPICAL CYCLONE PUBLIC ADVISORY 
PRODUCTS FOR THE ATLANTIC...EAST PACIFIC...AND CENTRAL PACIFIC 
HURRICANE BASINS: EFFECTIVE MAY 15 2009.

AN EXAMPLE OF THE TCP PRODUCT FOR 2009 IS PROVIDED ONLINE AT 
/USE LOWER CASE LETTERS/:

    HTTP://WWW.NHC.NOAA.GOV/TCP_EXAMPLE.SHTML

THE NHC IS RESPONSIBLE FOR ALL METEOROLOGICAL DECISIONS 
CONCERNING FORECASTING OF TROPICAL AND SUBTROPICAL SYSTEMS FOR 
THE ATLANTIC OCEAN AND THE EASTERN PACIFIC OCEAN...NORTH OF THE 
EQUATOR AND EAST OF 140 DEGREES WEST LONGITUDE.

IF YOU HAVE QUESTIONS...PLEASE CONTACT:

    TIMOTHY SCHOTT
    NATIONAL WEATHER SERVICE
    MARINE AND COASTAL SERVICES BRANCH
    1325 EAST WEST HWY ROOM 13124
    SILVER SPRING MARYLAND 20910
    PHONE:  301-713-1677 EXTENSION 122

THIS AND OTHER SERVICE CHANGE NOTICES CAN BE FOUND ONLINE AT  
/USE LOWER CASE LETTERS/:

    HTTP://WWW.NWS.NOAA.GOV/OM/NOTIF.HTM

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