233  
NOHW40 PHFO 232257  
PNSHFO  
HIZ001-003-004-006-007-009>011-015>018-022-023-026>054-241100-  
 
PUBLIC INFORMATION STATEMENT  
NATIONAL WEATHER SERVICE HONOLULU HI  
ISSUED BY NATIONAL WEATHER SERVICE SAN DIEGO CA  
1257 PM HST WED APR 23 2025  
 
TO: SUBSCRIBERS:  
-NOAA WEATHER WIRE SERVICE  
-EMERGENCY MANAGERS WEATHER INFORMATION NETWORK  
-NOAAPORT  
OTHER NWS PARTNERS AND NWS EMPLOYEES  
 
FROM: GREG SCHOOR, CHIEF  
MARINE, TROPICAL AND TSUNAMI SERVICES BRANCH  
 
SUBJECT: HURRICANE THREATS AND IMPACTS (HTI) MOSAIC TESTING ON  
APRIL 24, 2025 (BACKUP DATE: APRIL 29, 2025)  
 
THE NATIONAL WEATHER SERVICE (NWS) WEATHER FORECAST OFFICES  
(WFOS) IN HONOLULU, HAWAII, SAN JUAN, PUERTO RICO, AND ALL WFOS IN  
THE CONTIGUOUS UNITED STATES THAT CAN ISSUE TROPICAL STORM AND  
HURRICANE HAZARDS WILL COMMENCE WITH HURRICANE THREATS AND IMPACTS  
(HTI) THREAT GRID MOSAIC TESTING ON THURSDAY, APRIL 24, 2025.  
TESTING WILL BEGIN AT APPROXIMATELY 1500 UTC. TEST ACTIVITIES WILL  
TAKE APPROXIMATELY 1 HOUR. HOWEVER, NWS DISSEMINATION SYSTEMS MAY  
TAKE UP TO AN HOUR AND A HALF TO PURGE ALL TEST DATA. ALL TEST  
DATA IS EXPECTED TO BE CLEARED BY 1730 UTC.  
 
IN THE EVENT THAT THE COMMENCEMENT DATE IS DECLARED A CRITICAL  
WEATHER DAY (CWD), AN ENHANCED CAUTION EVENT, OR OTHER EVENT IS  
OCCURRING OR IS ANTICIPATED TO OCCUR, THE TESTING WILL COMMENCE AT  
THE AFFECTED OFFICES ON APRIL 29, 2025.  
 
FOR THE TEST, HTI GRIDS WILL BE CREATED FOR HURRICANE WIND  
THREAT, FLOODING RAIN THREAT, TORNADO THREAT, AND STORM SURGE  
THREAT (WHERE APPLICABLE) AT EACH PARTICIPATING WFO. THOSE GRIDS  
ARE STITCHED TOGETHER INTO STORM-SCALE HTI GRAPHICS. THE HTI  
MOSAIC GRAPHICS ARE AVAILABLE IN KEYHOLE MARKUP LANGUAGE (KML)  
FORMAT ON THE FOLLOWING WEBPAGE:  
HTTPS://WWW.WEATHER.GOV/HTI  
 
THE MOSAICS ARE ALSO AVAILABLE THROUGH THE NATIONAL DIGITAL  
FORECAST DATABASE AND ON WEB PAGES HOSTED BY THE WEATHER FORECAST  
OFFICES (WFOS) AFFECTED BY TROPICAL CYCLONES. THESE WEBPAGES  
INCLUDE WFO TROPICAL WEBPAGES AND GRAPHICAL HAZARDOUS WEATHER  
OUTLOOK (GHWO) WEBPAGES.  
 
GHWO WEBPAGES USE THE FOLLOWING URL FORMAT, WHERE “XXX” SHOULD BE  
REPLACED WITH THE 3-LETTER IDENTIFIER FOR THE WFO OF INTEREST  
(NOTE THAT WFO HONOLULU DOES NOT HAVE A GHWO WEBPAGE):  
HTTPS://WWW.WEATHER.GOV/ERH/GHWO?WFO=XXX  
 
WFO 3-LETTER IDENTIFIERS AND THE RESPECTIVE NWS REGION THAT EACH  
WFO BELONGS TO IS LISTED AT THE FOLLOWING PAGE:  
HTTPS://WWW.WEATHER.GOV/PIMAR/CWABYWFO  
 
NWS EASTERN, SOUTHERN, AND WESTERN REGION WFO TROPICAL WEBPAGES  
USE THE FOLLOWING URL FORMAT, WHERE “XXX” SHOULD BE REPLACED WITH  
THE 3 LETTER IDENTIFIER FOR THE WFO OF INTEREST:  
 
NWS EASTERN REGION WFOS:  
HTTPS://WWW.WEATHER.GOV/XXX/TROPICAL#HTI  
 
NWS SOUTHERN REGION AND WESTERN REGION WFOS:  
HTTPS://WWW.WEATHER.GOV/SRH/TROPICAL?OFFICE=XXX#HTI  
 
THE TROPICAL WEBPAGE FOR WFO HONOLULU CAN BE FOUND AT:  
HTTPS://WWW.WEATHER.GOV/HFO/HTI  
 
USER INFORMATION ABOUT HTI CAN BE FOUND HERE:  
HTTPS://WWW.WEATHER.GOV/MEDIA/SRH/TROPICAL/HTI_EXPLANATION.PDF  
 
MORE SPECIFIC DETAILS ON HTI CAN BE FOUND IN THE PRODUCT DESCRIPTION DOCUMENT:  
HTTPS://WWW.WEATHER.GOV/MEDIA/SRH/TROPICAL/PDD_HTI.PDF  
 
PERIODIC SOFTWARE AND HARDWARE TESTING IN PREPARATION FOR  
TROPICAL CYCLONE EVENTS WILL CONTINUE DURING THE REMAINDER OF  
2025.  
 
FOR MORE INFORMATION, PLEASE CONTACT:  
 
CHRISTOPHER BRENCHLEY  
METEOROLOGIST IN CHARGE  
NATIONAL WEATHER SERVICE OFFICE HONOLULU, HAWAII  
CHRISTOPHER.BRENCHLEY@NOAA.GOV  
 
NATIONAL PUBLIC INFORMATION STATEMENTS ARE ONLINE AT:  
HTTPS://WWW.WEATHER.GOV/NOTIFICATION/  
 
 
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