Area forecast

An Aviation Area Forecast or FA or ARFOR 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. FAs are issued three times daily in all 48 neighboring states of the United States, and modified as required. The National Weather Service (NWS) offices issue FAs for Alaska and Hawaii, 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)
• Comprising four sections
  • a. A communications and header section
    • i. Issue time of forecast
    • ii. Valid times of the synopsis and the VFR CLOUDS/WX sections
    • iii. Area of coverage
  • b. A precautionary statement section
    • i. Warns users to check the AIRMET section for IFR and/or mountain obscuration
    • ii. Describes the hazards associated with all thunderstorm
    • iii. Reminds users that all altitudes are given in MSL, unless noted as AGL or CIG (ceiling)
  • c. A synopsis section
    • i. Brief summary of the location and movement of fronts, pressure systems and circulation patterns for an 18 hour period
    • ii. References to low ceilings, reduced visibility and/or strong winds may be included
  • d. A VFR CLOUDS/WX section
    • i. Contains a 12 hour specific forecast, followed by a 6 hour categorical outlook
    • ii. Broken down into geographical areas, and/or states
    • iii. 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

Some abbrevaitions that are used in FA's include:

• OCNL Occasional >50% chance for <1/2 of the forecast period
• ISOLD Isolated Single cells
• WDLY SCT Widely scattered <25% of the area affected
• SCT Scattered Areas of 25% to 54% of the area affected
• NMRS Numerous >55% of the area affected
• WDSPRD Wide spread >55% of the area affected

Status of an FA can be:

• AMD Amended Includes AIRMETs, SIGMETs, and Convective SIGMETs
• COR Corrected
• RTD Delayed