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NOUS41 KWBC 171450
PNSWSH
SERVICE CHANGE NOTICE 25-72
NATIONAL WEATHER SERVICE HEADQUARTERS SILVER SPRING MD
1050 AM EDT WED SEP 17 2025
TO: SUBSCRIBERS:
-NOAA WEATHER WIRE SERVICE
-EMERGENCY MANAGERS WEATHER INFORMATION NETWORK
-NOAAPORT
OTHER NWS PARTNERS AND NWS EMPLOYEES
FROM: STEPHEN BIEDA III, PH.D., CHIEF
SEVERE, FIRE, PUBLIC, AND WINTER WEATHER SERVICES
BRANCH
SUBJECT: OPERATIONAL IMPLEMENTATION OF CHANGES TO THE WINTER
STORM SEVERITY INDEX ON OR ABOUT OCTOBER 17, 2025.
THE NATIONAL WEATHER SERVICE (NWS) WILL IMPLEMENT CHANGES TO THE
WINTER STORM SEVERITY INDEX (WSSI) ON OR ABOUT OCTOBER 17, 2025.
THOSE CHANGES INCLUDE:
- THE REMOVAL OF THE "GROUND BLIZZARD" COMPONENT AS ITS
UNDERLYING SCIENTIFIC PRINCIPLES ARE INTEGRATED INTO THE
"BLOWING SNOW" COMPONENT.
- THE REMOVAL OF THE “FLASH FREEZE” COMPONENT DUE TO
CHALLENGES WITH STANDARD DEFINITION AND VERIFICATION
THE PURPOSE OF THE WSSI IS TO PROVIDE NWS FORECASTERS, PARTNERS,
AND THE PUBLIC WITH AN INDICATION OF THE SEVERITY OF WINTER
WEATHER HAZARDS AND THE POTENTIAL FOR RELATED SOCIETAL IMPACTS.
THE WSSI DOES NOT DEPICT OFFICIAL WARNINGS AND SHOULD ALWAYS BE
USED IN CONTEXT WITH OFFICIAL NWS FORECASTS AND WARNINGS.
THE WSSI IS UPDATED EVERY TWO HOURS AT APPROXIMATELY 0100
COORDINATED UNIVERSAL TIME (UTC), 0300 UTC, 0500 UTC, ETC. NO
COMMUNICATION SYSTEM CHANGES ARE REQUIRED TO VIEW THIS WEB-BASED
INFORMATION.
ADDITIONAL INFORMATION IS PROVIDED IN THE PRODUCT DESCRIPTION
DOCUMENT (PDD) AT THE LINK BELOW:
HTTPS://NSDESK.SERVICENOWSERVICES.COM/API/G_NOA/NWSPC/RES2/26206
AB01B40F6100D690F67624BCB9C
THE WSSI WEBSITE IS AVAILABLE HERE:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/WWD/WSSI/WSSI.PHP
FOR QUESTIONS REGARDING THE WSSI, PLEASE CONTACT:
JAMES NELSON
BRANCH CHIEF, DEVELOPMENT AND TRAINING BRANCH
NATIONAL WEATHER SERVICE - WEATHER PREDICTION CENTER
COLLEGE PARK, MD
EMAIL: JAMES.A.NELSON@NOAA.GOV
ERIC GUILLOT
WINTER WEATHER PROGRAM LEAD
NATIONAL WEATHER SERVICE - ANALYZE, FORECAST, AND SUPPORT OFFICE
STERLING, VA
EMAIL: ERIC.GUILLOT@NOAA.GOV
NWS SERVICE CHANGE NOTICES ARE ONLINE AT:
HTTPS://WWW.WEATHER.GOV/NOTIFICATION/
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