Categorical Amendment Criteria (CAC)
The standard CAC categories and thresholds are shown below. The complete list of airport specific thresholds for NWS TAF locations can be found in Appendix F, NWSI 10-813.
- Category A is the Airport Landing Minimums.
- Category B refers to the Airport Alternate Minimums.
- Category C is the Instrument Flight Rules (IFR). Cloud ceilings less than 1000 ft and/or visibilities less than 3 statute miles.
- Category D is for Marginal Visual Flight Rule (MVFR) conditions. Cloud ceilings > 1,000 to < 3,000 ft and/or visibilities > 3 to < 5 statute miles.
- Category E is alternate fuel criteria for destination airports under IFR conditions.
- Category F is for other conditions defined by local airport or air traffic managers.