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PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE MELBOURNE FL
418 PM EDT 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:
MATTHEW VOLKMER
SCIENCE AND OPERATIONS OFFICER
NATIONAL WEATHER SERVICE OFFICE
MELBOURNE, FL
MATTHEW.VOLKMER@NOAA.GOV
NATIONAL PUBLIC INFORMATION STATEMENTS ARE ONLINE AT:
HTTPS://WWW.WEATHER.GOV/NOTIFICATION/
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