898  
NOUS41 KLWX 071901  
PNSLWX  
DCZ001-MDZ001-003>006-008-011-013-014-016>018-501>508-VAZ025>031-  
036>040-050>057-501>508-WVZ050>053-055-501>506-080315-  
 
PUBLIC INFORMATION STATEMENT  
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC  
301 PM EDT WED APR 7 2021  
 
TO: SUBSCRIBERS:  
-NOAA WEATHER WIRE SERVICE  
-EMERGENCY MANAGERS WEATHER INFORMATION NETWORK  
-NOAAPORT  
OTHER NWS PARTNERS AND NWS EMPLOYEES  
 
FROM: ALLISON ALLEN, CHIEF  
MARINE, TROPICAL AND TSUNAMI SERVICES BRANCH  
 
SUBJECT: HURRICANE THREATS AND IMPACTS (HTI) MOSAIC TESTING ON  
APRIL 8, 2021 (BACKUP DATE: APRIL 22, 2021)  
 
THE NWS WEATHER FORECAST OFFICE (WFO) IN HONOLULU, AND WFOS IN THE  
NWS SOUTHERN REGION AND IN THE NWS EASTERN REGION WILL COMMENCE  
WITH HURRICANE THREATS AND IMPACTS (HTI) THREAT GRID MOSAIC  
TESTING ON THURSDAY, APRIL 8. THURSDAY, APRIL 22 HAS BEEN  
DESIGNATED AS THE BACKUP TEST DATE IN THE EVENT THAT TESTING  
CANNOT BE CONDUCTED ON APRIL 8.  
 
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.  
 
FOR THE TEST, HTI GRIDS WILL BE CREATED FOR HURRICANE WIND THREAT,  
HURRICANE STORM SURGE THREAT,HURRICANE FLOODING RAIN THREAT, AND  
HURRICANE TORNADO THREAT. THESE GRIDS ARE SENT TO THE NATIONAL  
DIGITAL FORECAST DATABASE (NDFD) AND CAN BE SEEN ON THE NDFD WEB  
VIEWER AT: HTTPS://DIGITAL.WEATHER.GOV  
 
THE PRODUCT DESCRIPTION DOCUMENT FOR THESE THREAT GRIDS CAN BE  
FOUND HERE: HTTPS://WWW.WEATHER.GOV/MEDIA/SRH/TROPICAL/PDD_HTI.PDF  
 
HTI GRIDS ARE CREATED BY WFOS FOR THEIR COUNTY WARNING AREA AND  
MOSAICKED TOGETHER TO FORM A MORE GEOGRAPHICALLY CONSISTENT  
DEPICTION OF THE THREAT POSED BY HURRICANE HAZARDS. THE HTI  
MOSAICS CAN BE FOUND IN KML FORMAT AT: HTTPS://WEATHER.GOV/HTI  
 
WHEN POPULATED HTI GRIDS ARE POSTED, THEY ALSO CAN BE FOUND ON  
THE WFO TROPICAL WEB PORTAL PAGE LINKED BELOW UNDER THE  
THREATS AND IMPACTS TAB: HTTPS://WWW.WEATHER.GOV/SRH/TROPICAL  
 
PERIODIC SOFTWARE AND HARDWARE TESTING IN PREPARATION FOR TROPICAL  
CYCLONE EVENTS WILL CONTINUE DURING THE REMAINDER OF 2021.  
 
FOR MORE INFORMATION, PLEASE CONTACT:  
 
CHRIS STRONG  
WARNING COORDINATION METEOROLOGIST  
NATIONAL WEATHER SERVICE OFFICE  
STERLING VA 20166  
CHRISTOPHER.STRONG@NOAA.GOV  
571-888-3500  
 
NATIONAL PUBLIC INFORMATION STATEMENTS ARE ONLINE AT:  
HTTPS://WWW.WEATHER.GOV/NOTIFICATION/  
 

 
ADM  
 
CLICK HERE TO GO TO PREVIOUS BULLETINS.

The Nexlab VA Page
The Nexlab MD Page
The Nexlab WV Page Main Text Page