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Service Change Notice 24-85
National Weather Service Headquarters Silver Spring MD
1055 AM EDT Wed Aug 28 2024

To: Subscribers:
 -NOAA Weather Wire Service
 -Emergency Managers Weather Information Network
 -NOAAPort
 Other NWS Partners, Users and Employees

From: C. Bruce Entwistle, Chief
 Aviation and Space Weather Services Branch

Subject: Updated PROB30 Usage in the Terminal Aerodrome Forecast
(TAF): Effective on or about September 30, 2024

The NWS since 2002 has not allowed the term PROB30 in the first
nine hours of the TAF.This restriction will end on or about
September 30, 2024.  This change aligns the U.S. TAF product
with the International Civil Aviation Organization`s (ICAO`s)
Annex 3, Meteorological Service for International Air
Navigation, and improves consistency of the TAF with probability
of precipitation forecasts in other NWS products.

If you have comments or questions, please contact:

Michael L. Graf
Meteorologist/International Liaison
NWS Headquarters
Silver Spring, MD
301-427-9109
michael.graf@noaa.gov

National Service Change Notices are online at:

https://www.weather.gov/notification