062  
NOUS42 KCAE 071810  
PNSCAE  
GAZ040-063>065-077-SCZ016-018-020>022-025>031-035-037-038-041-115-  
116-135>137-080615-  
 
PUBLIC INFORMATION STATEMENT  
NATIONAL WEATHER SERVICE COLUMBIA SC  
210 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:  
 
RICHARD OKULSKI METEOROLOGIST-IN-CHARGE  
NATIONAL WEATHER SERVICE COLUMBIA SC  
2909 AVIATION WAY  
WEST COLUMBIA, SC 29170  
RICHARD.OKULSKI@NOAA.GOV  
803-765-5501 EXT. 222  
PUBLIC INFORMATION STATEMENTS ARE ONLINE AT:  
HTTPS://WWW.WEATHER.GOV/NOTIFICATION/  
 

 
 
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