Public Information Statement
National Weather Service Albany NY
313 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:
 
Christopher Gitro
Meteorologist-in-Charge
National Weather Service Office 
Albany, NY
christopher.gitro@noaa.gov

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