870  
NOUS41 KBOX 071835  
PNSBOX  
CTZ002>004-MAZ002>024-026-RIZ001>008-081800-  
 
PUBLIC INFORMATION STATEMENT  
NATIONAL WEATHER SERVICE BOSTON/NORTON MA  
235 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  
 
THE NWS WEATHER FORECAST OFFICE (WFO) IN BOSTON/NORTON, MA AND  
WFOS IN NWS EASTERN REGION, NWS SOUTHERN REGION, AND WFO HONOLULU  
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 (11 AM EDT). TEST  
ACTIVITIES WILL TAKE APPROXIMATELY ONE 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  
(130 PM EDT).  
 
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 CAN ALSO 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:  
 
ANDY NASH  
METEOROLOGIST-IN-CHARGE  
NATIONAL WEATHER SERVICE OFFICE  
46 COMMERCE WAY  
NORTON, MA 02766  
ANDY.NASH@NOAA.GOV  
508-622-3250  
 
NATIONAL PUBLIC INFORMATION STATEMENTS ARE ONLINE AT:  
HTTPS://WWW.WEATHER.GOV/NOTIFICATION  
 

 
 
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