National Weather Service United States Department of Commerce

Aviation Weather Services


Categorical Amendment Criteria PictureThe National Weather Service (NWS) utilizes Categorical Amendment Criteria (CAC) based on information contained in the Federal Aviation Administration's (FAA) approach plates to optimally create and amend Terminal Aerodrome Forecasts (TAFs). The idea is to provide a customer-based approach for NWS forecasters that best addresses the needs of the National Airspace System and highlight the greatest weather-related impacts.

Below are a collection of documents and training materials designed to inform NWS meteorologists of the latest information provided by the FAA and how to most effectively provide optimal TAFs using local office software. This includes information on terminal-specific Categorical Amendment Criteria (CAC) and how the NWS uses Categorical Amendment Criteria (CAC) in forecast operations.


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