721
NOUS42 KGSP 232155
PNSGSP
GAZ010-017-018-026-028-029-NCZ033-035>037-048>053-056>059-062>065-
068>072-082-501>510-SCZ008>014-019-101>109-241000-

Public Information Statement
National Weather Service Greenville-Spartanburg SC
555 PM EDT 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:
Stephen Wilkinson
Meteorologist in Charge
National Weather Service Office
Greenville/Spartanburg, SC
stephen.wilkinson@noaa.gov

National Public Information Statements are online at:
https://www.weather.gov/notification/

$$