A Terminal Aerodrome Forecast (TAF) covers what area and time period?
AA 25-mile radius around the airport, valid for 12 hours.
BA 5 statute mile radius around the airport, valid for 24 or 30 hours, updated four times daily.✓
CThe entire terminal control area, valid for 6 hours and updated hourly.
Why →TAFs are aerodrome-specific weather forecasts for a 5 SM radius. They are valid for 24 or 30 hours and issued four times daily at 0000Z, 0600Z, 1200Z, and 1800Z. TAFs use the same encoding as METARs and include change groups (TEMPO, BECMG, FM) for expected condition transitions.
The trap →Hourly updates are METARs; TAFs are issued four times a day. And the 5 SM radius is far smaller than an Area Forecast covers.
Field note →Look for TEMPO or FM groups in the TAF indicating wind shifts, visibility drops, or thunderstorm probability before your planned flight window. PROB30 means 30% probability of that condition. Treat PROB30 for thunderstorms as a serious factor.
SOURCE → FAA Aviation Weather Services / PHAK Chapter 13CHECKED JUL 16ACS III.A.K1MED