An Aviation Area Forecast (FA or ARFOR) is a message product of the National Weather Service (NWS) in the United States. There are also weather charts forecast like SIGWX. FA encompasses the weather conditions over a large regional area and is considered one of the better sources of information for en-route weather. It is also beneficial in verifying airport conditions at airports that do not have terminal aerodrome forecasts. FA's are issued three times daily in all 48 contiguous states of the United States, and modified as required. The NWS offices also issue FA's for Alaska and Hawaii, but Alaska uses a slightly different format.
Area forecasts (FA's):
Issued 3 times dailyValid for 18 hours (12-hour forecast, plus 6-hour categorical outlook)Cover an area the size of several statesVisibility is always stated in statute miles (SM)Times are issued in UTC (Coordinated Universal Time)Comprise four sectionsa. A communications and header sectioni. Issue time of forecastii. Valid times of the synopsis and the visual flight rules (VFR) CLOUDS/WX sectionsiii. Area of coverageb. A precautionary statement sectioni. Warns users to check the AIRMET section for IFR and/or mountain obscurationii. Describes the hazards associated with all thunderstormiii. Reminds users that all altitudes are given in MSL, unless noted as AGL or CIG (ceiling)c. A synopsis sectioni. Brief summary of the location and movement of fronts, pressure systems and circulation patterns for an 18-hour periodii. References to low ceilings, reduced visibility and/or strong winds may be includedd. A VFR CLOUDS/WX sectioni. Contains a 12-hour specific forecast, followed by a 6-hour categorical outlookii. Broken down into geographical areas, and/or statesiii. Describes cloud and weather affecting VFR flight operations, including precipitation, thunderstorms, and sustained surface winds 20 Kts or greater. Also includes visibility when the forecast to visibility is between 3 and 6 SM and/or obstructions to visibilitySome abbreviations that are used in FA's include:
OCNL Occasional >50% chance for <1/2 of the forecast periodISOLD Isolated Single cellsWDLY SCT Widely scattered <25% of the area affectedSCT Scattered Areas of 25% to 54% of the area affectedNMRS Numerous >55% of the area affectedWDSPRD Widespread >55% of the area affectedStatus of an FA can be:
AMD Amended Includes AIRMETs, SIGMETs, and Convective SIGMETsCOR CorrectedRTD Delayed