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PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE HUNTSVILLE AL
218 PM CDT MON APR 20 2026
TO: SUBSCRIBERS:
-NOAA WEATHER WIRE SERVICE
-EMERGENCY MANAGERS WEATHER INFORMATION NETWORK
-NOAAPORT
OTHER NWS PARTNERS AND NWS EMPLOYEES
FROM: JAMIE RHOME, DEPUTY DIRECTOR
NATIONAL HURRICANE CENTER
SUBJECT: HURRICANE THREATS AND IMPACTS (HTI) MOSAIC TESTING ON APRIL 21,
2026 (BACKUP DATE: APRIL 23, 2026)
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 TUESDAY, APRIL 21, 2026. 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 TEST NEEDS TO BE POSTPONED, DUE TO WEATHER OR ANOTHER
EVENT, THE TESTING WILL INSTEAD COMMENCE AT THE AFFECTED OFFICES ON APRIL
23, 2026.
FOR THE TEST, HTI GRIDS WILL BE CREATED FOR TROPICAL 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 2026.
FOR MORE INFORMATION, PLEASE CONTACT:
KATE GUILLET
WARNING COORDINATION METEOROLOGIST
NATIONAL WEATHER SERVICE OFFICE
HUNTSVILLE, ALABAMA
KATE.GUILLET@NOAA.GOV
NATIONAL PUBLIC INFORMATION STATEMENTS ARE ONLINE AT:
HTTPS://WWW.WEATHER.GOV/NOTIFICATION/
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