- Area forecast
An Aviation Area Forecast or FA encompasses the
weather conditions over a large regional area and is considered one of the better sources of information for enroute weather. It is also beneficial in verifying airport conditions at airports that do not have terminalaerodrome forecasts. FAs are issued three times daily in all 48 neighboring states of theUnited States , and modified as required. TheNational Weather Service (NWS) offices issue FAs forAlaska andHawaii , but Alaska uses a slightly different format. Issued 3 times Daily Valid for 18 hours (12 hour forecast, plus 6 hour categorical outlook) Covers an area the size of several states Visibility is always in statute miles (SM) Comprised of four sectionsa. A communications and header sectioni. Issue time of forecastii. Valid times of the synopsis and the 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 winds >20 kts. Also includes visibility and/or obstructions to vision when the forecast to visibility is <6 sm
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 Wide spread >55% of the area affected AMD Amended Includes AIRMETs, SIGMETs, and Convective SIGMETsCOR Corrected RTD Delayed
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