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NOUS41 KWBC 241330
PNSWSH
SERVICE CHANGE NOTICE 26-31
NATIONAL WEATHER SERVICE HEADQUARTERS SILVER SPRING MD
930 AM EDT TUE MAR 24 2026
TO: SUBSCRIBERS:
-NOAA WEATHER WIRE SERVICE
-EMERGENCY MANAGERS WEATHER INFORMATION NETWORK
-NOAAPORT
OTHER NWS PARTNERS, USERS AND EMPLOYEES
FROM: JAMIE RHOME, DEPUTY DIRECTOR
NATIONAL HURRICANE CENTER
SUBJECT: EXPANSION OF STORM SURGE WATCH AND WARNING, POTENTIAL
STORM SURGE FLOODING MAP, AND THE PEAK STORM SURGE FORECAST
GRAPHIC TO HAWAII EFFECTIVE ON OR ABOUT JUNE 1, 2026
ON OR ABOUT JUNE 1, 2026, THE STORM SURGE WATCH AND WARNING,
POTENTIAL STORM SURGE FLOODING MAP, AND THE PEAK STORM SURGE
FORECAST GRAPHIC WILL BE EXPANDED TO INCLUDE HAWAII. THESE
PRODUCTS AND GRAPHICS WERE PREVIOUSLY ONLY PRODUCED FOR ATLANTIC
BASIN TROPICAL CYCLONES THAT IMPACTED THE U.S. GULF AND ATLANTIC
COAST, PUERTO RICO, AND THE U.S. VIRGIN ISLANDS.
1. STORM SURGE WATCH AND WARNING
THE STORM SURGE WATCHES AND WARNINGS HIGHLIGHT AREAS THAT HAVE A
SIGNIFICANT RISK OF LIFE-THREATENING STORM SURGE INUNDATION FROM
A TROPICAL STORM OR HURRICANE.
A STORM SURGE WATCH IS DEFINED AS THE POSSIBILITY OF LIFE-
THREATENING INUNDATION FROM RISING WATER MOVING INLAND FROM THE
SHORELINE SOMEWHERE WITHIN THE SPECIFIED AREA, GENERALLY WITHIN
48 HOURS, IN ASSOCIATION WITH A TROPICAL, SUBTROPICAL, OR POST-
TROPICAL CYCLONE.
A STORM SURGE WARNING IS DEFINED AS THE DANGER OF LIFE-
THREATENING INUNDATION FROM RISING WATER MOVING INLAND FROM THE
SHORELINE SOMEWHERE WITHIN THE SPECIFIED AREA, GENERALLY WITHIN
36 HOURS, IN ASSOCIATION WITH A TROPICAL, SUBTROPICAL, OR POST-
TROPICAL CYCLONE.
STORM SURGE WATCHES AND WARNINGS ARE DISSEMINATED VIA THE
WEATHER FORECAST OFFICE (WFO) TROPICAL CYCLONE WATCH/WARNING
(TCV) TEXT PRODUCT AND FOR HAWAII THIS IS DISSEMINATED VIA THE
FOLLOWING:
PRODUCT TITLE AWIPS PIL WMO ID
—------------ —--------—----------
TROPICAL CYCLONE WATCH/ TCVHFO WTHW80 PHFO
WARNING (TCV)
THE STORM SURGE WARNING WILL ALERT VIA WIRELESS EMERGENCY ALERTS
(WEA). ADDITIONAL INFORMATION ON WIRELESS EMERGENCY ALERTS CAN
BE FOUND AT HTTPS://WWW.WEATHER.GOV/WRN/WEA.
A GRAPHICAL DEPICTION OF THE STORM SURGE WATCH/WARNING AND GIS
FILES ARE AVAILABLE AT HTTPS://WWW.HURRICANES.GOV.
2. POTENTIAL STORM SURGE FLOODING MAP
THE POTENTIAL STORM SURGE FLOODING MAP SHOWS GEOGRAPHICAL AREAS
WHERE INUNDATION FROM STORM SURGE COULD OCCUR AND HOW HIGH ABOVE
GROUND THE WATER COULD REACH IN THOSE AREAS. THE MAP REPRESENTS
INUNDATION LEVELS THAT HAVE A 1 IN 10 CHANCE OF BEING EXCEEDED
AND THEREFORE REPRESENTS A REASONABLE WORST CASE SCENARIO FOR
ANY INDIVIDUAL LOCATION.
THIS MAP IS TYPICALLY FIRST AVAILABLE WHEN NHC ISSUES A STORM
SURGE WATCH OR WARNING, BUT NHC MAY CHOOSE TO ISSUE IT AS EARLY
AS 72 HOURS IN ADVANCE OF HAZARDOUS WEATHER CONDITIONS WHEN
FORECAST CONFIDENCE IS HIGH.
THE POTENTIAL STORM SURGE FLOODING MAP IS AVAILABLE IN AN
INTERACTIVE MAP AND VIA GIS FILES AT HTTPS://WWW.HURRICANES.GOV.
3. PEAK STORM SURGE FORECAST GRAPHIC
THE PEAK STORM SURGE FORECAST GRAPHIC DEPICTS THE HEIGHT THAT
WATER COULD REACH ABOVE NORMALLY DRY GROUND (INUNDATION)
SOMEWHERE WITHIN THE SPECIFIC AREAS ALONG THE IMMEDIATE COAST.
THE GRAPHIC IS TYPICALLY AVAILABLE WHEN NHC ISSUES A STORM SURGE
WATCH OR WARNING, HOWEVER, NHC MAY CHOOSE TO ISSUE IT AT OTHER
TIMES IF CONDITIONS WARRANT.
THE PEAK STORM SURGE FORECAST GRAPHIC IS AVAILABLE AS A STATIC
GRAPHIC AND VIA GIS FILES AT HTTPS://WWW.HURRICANES.GOV.
MORE INFORMATION ON THE STORM SURGE WATCH AND WARNING, POTENTIAL
STORM SURGE FLOODING MAP, AND THE PEAK STORM SURGE FORECAST
GRAPHIC CAN BE FOUND AT THE FOLLOWING URL:
HTTPS://WWW.NHC.NOAA.GOV/ABOUTNHCGRAPHICS.SHTML?
IF YOU HAVE QUESTIONS REGARDING THIS NOTICE, PLEASE CONTACT:
NWS TROPICAL PROGRAM
NATIONAL HURRICANE CENTER
EMAIL: TROPICAL.PROGRAM@NOAA.GOV
NATIONAL SERVICE CHANGE NOTICES ARE ONLINE AT:
HTTPS://WWW.WEATHER.GOV/NOTIFICATION
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