An area forecast is an aviation weather forecast for regions of the United States and coastal waters. It is used with other aviation weather products to gain a good picture of forecasted weather, and provide forecast coverage to airports for which a terminal aerodrome forecast is not issued. In contrast to a terminal aerodrome forecast, which forecasts weather for a particular airport, an area forecast is not issued for one specific airport.
Area forecasts are issued for six geographic areas, covering the continental United States. They are:
Additionally, area forecasts are issued for Alaska, Hawaii, and the Caribbean.
An area forecast provides forecasted thunderstorms, precipitation, cloud heights and tops, cloud amount, obstructions to visibility – such as fog or haze, and sustained surface winds of 20 knots or greater in speed. An area forecast does not provide hazardous weather information, since it is not meant to be used by itself. Pilots must use available weather reports and forecasts together to form a mental picture of the current and expected weather.
An area forecast contains four sections:
Header
The header contains information about the forecast, such as who issued it, when it was issued, the time frame of the forecast, and the forecast area.
Example: CHIC FA 011845 SYNOPSIS AND VFR CLDS/WX SYNOPSIS VALID UNTIL 021300 CLDS/WX VALID UNTIL 020700...OTLK VALID 020700-021300 ND SD NE KS MN IA MO WI LM LS MI LH IL IN KY
This example header shows this forecast is for the Chicago region, and is a VFR Clouds and Weather area forecast, FA being the contraction which denotes an area forecast. The report was issued on the first day of the month, at 1845 Zulu time. Since Zulu time uses the 24 hour clock, 1845 Zulu equates to 6:45 PM, Greenwich time, which is 12:45 PM in the central time zone of the United States, central time being 6 hours behind Greenwich.
In this example, if it were daylight savings time, central time would only be five hours behind Greenwich, making the report issuance time 1:45 PM central time. Next, the report states this area forecast contains a synopsis and VFR clouds and weather. The synopsis is valid until the second day of the month at 1300 Zulu. The clouds and weather portion of the forecast is valid until the second day of the month at 0700 Zulu, and the outlook is valid from the second day of the month at 0700 Zulu until the second day of the month at 1300 Zulu.
The final line in the header describes the area for which the forecast is valid.
Example:
MIAC FA 011745 SYNOPSIS AND VFR CLDS/WX SYNOPSIS VALID UNTIL 021200 CLDS/WX VALID UNTIL 020600...OTLK VALID 020600-021200 NC SC GA FL AND CSTL WTRS E OF 85W
Here’s another header example. The forecast is valid for the Miami area, and is a VFR clouds and weather area forecast, issued on the first day of the month at 1745 Zulu. Since eastern time is 5 hours behind Greenwich time, 1745 Zulu is equal to 12:45 PM eastern standard time, or 1:45 PM eastern daylight savings time. The forecast contains a synopsis and VFR clouds and weather. The synopsis is valid until the second day of the month at 1200 Zulu. The clouds and weather portion of the forecast is valid until the second day of the month at 0600 Zulu, and the outlook is valid between the second day of the month at 0600 Zulu and the second day of the month at 1200 Zulu. This area forecast is valid for North Carolina, South Carolina, Georgia, Florida, and coastal waters east of 85 degrees west longitude.
Header Amendments and Corrections
If the letters “AMD” appear in the header just after the date time group, the forecast has been amended to reflect weather not developing or improving as originally forecast.
Example:
MIAC FA 011745 AMD SYNOPSIS AND VFR CLDS/WX SYNOPSIS VALID UNTIL 021200 CLDS/WX VALID UNTIL 020600...OTLK VALID 020600-021200 NC SC GA FL AND CSTL WTRS E OF 85W
The letters “COR” just after the date time group indicates the area forecast contained an error, which has been corrected.
Example:
MIAC FA 011745 COR SYNOPSIS AND VFR CLDS/WX SYNOPSIS VALID UNTIL 021200 CLDS/WX VALID UNTIL 020600...OTLK VALID 020600-021200 NC SC GA FL AND CSTL WTRS E OF 85W
If the header of an area forecast indicates it has been amended or corrected, the letters “UPDT”, for update, will be printed in the forecast following the affected geographical area.
Precautionary Statements
Precautionary statements follow the header. They point the reader to check and use other weather products, since the area forecast will not include hazardous weather information. Also included is a reminder that heights in an area forecast are stated in reference to sea level, unless they are heights of cloud ceilings or the forecast specifically states otherwise.
Example:
SEE AIRMET SIERRA FOR IFR CONDS AND MTN OBSCN. TS IMPLY SEV OR GTR TURB SEV ICE LLWS AND IFR CONDS. NON MSL HGTS DENOTED BY AGL OR CIG.
This example reads: See airmet sierra for IFR conditions and mountain obscuration. Thunderstorms imply severe or greater turbulence, severe icing, low level wind shear, and IFR conditions. Non MSL heights denoted by “AGL” or “CIG”.
Synopsis
Next is the synopsis, which summarizes the location and movement of fronts and weather systems.
Example:
SYNOPSIS...CDFNT ERN UPR MI-SERN WI-NWRN IL-SWRN MO-NERN OK FCST 13Z SRN IN-MO BOOTHEEL-NERN AR. TROF OF LOW PRES DVLPG 12-13Z WRN ND-WRN SD-PNHDL NE.
This example synopsis reads: Synopsis…cold front eastern to upper Michigan to southeastern Wisconsin to northwestern Illinois to southwestern Missouri to northeastern Oklahoma forecast at 1300 Zulu southern Indiana to Missouri boot heel to northern ArKansas. Trough of low pressure developing 1200 to 1300 Zulu western North Dakota to western South Dakota to the Nebraska panhandle.
Example:
SYNOPSIS...STNR FNT EXTDS FM VA CSTL WTRS THRU NRN GA-NRN AL. BNDRY WL TEND LIFT NWD AS A WRMFNT INTO THE MID ATLC RGN BY 12Z. DEEPER MSTR AND INSTBY EXTDS FM NC CSTL WTRS/NC CSTL PLAIN THRU SRN GA AND NRN FL. DEEPENING MSTR WL DVLP BTN 06Z AND 12Z ACRS NRN GA INTO WRN NC WV AND WRN VA.
This synopsis from a recent Miami area forecast reads: Synopsis…Stationary front extends from Virginia coastal waters through northern Georgia to northern Alabama. Boundary will trend to lift northward as a warm front into the mid Atlantic region by 1200 Zulu. Deeper moisture and instability extends from north Carolina coastal waters and north Carolina coastal plain through southern Georgia and northern Florida.
Deepening moisture will develop between 0600 Zulu and 1200 Zulu across northern Georgia into western north Carolina, west Virginia, and western Virginia.
VFR Clouds and Weather
The VFR clouds and weather section describes VFR and marginal VFR clouds, visibilities, precipitation, and widespread sustained surface winds of 20 knots or more in speed. VFR weather conditions exist when the cloud ceiling is 3,000 feet or more above the ground, with a visibility of five statute miles or greater. Marginal VFR weather conditions exist with cloud ceilings between 1,000 and 3,000 feet, and visibilities between three and five statute miles. The forecast period is 12 hours in duration, with a categorical outlook period extending an additional six hours.
Example:
ND
W HLF...SKC. TIL 01Z SCT150. OTLK...VFR.
E HLF...SCT-BKN070 TOP 080. 01Z SKC. OTLK...VFR.
NE
SCT050-070. 01Z SCT CI TO SKC. OTLK...VFR.
IN
SERN...SCT060 BKN CI. 21Z BKN060. NMRS -SHRA. WDLY SCT
-TSRA. CB TOP FL300. OTLK...VFR..11Z MVFR CIG.
RMNDR...OVC060 LYRD FL250. SCT/NMRS -SHRA. WDLY SCT -TSRA. CB TOP
FL300. 04Z SCT020 BKN040. OTLK...MVFR BR CIG.
This example reads: North Dakota, Western Half, Sky clear. Until 0100 Zulu, scattered clouds at 15,000 feet. Outlook…VFR. Eastern half, scattered to broken clouds at 7,000 feet with tops at 8,000 feet. 0100 Zulu, sky clear. Outlook, VFR.
Nebraska…Scattered clouds with bases between five and seven thousand feet. 0100 Zulu, scattered cirrus to sky clear. Outlook…VFR.
Indiana… Southern…scattered clouds at 6,000 feet with broken cirrus. 2100 Zulu, broken clouds at 6,000 feet. Numerous light rain showers. Widely scattered thunderstorms with light rain. Cumulonimbus tops to flight level three zero zero. Outlook, VFR…at 1100 Zulu, Marginal VFR ceilings. Remainder…Overcast at 6,000 feet. Scattered to numerous light rain showers. Widely scattered thunderstorms with light rain. Cumulonimbus tops to flight level three zero zero. 0400 Zulu, scattered clouds at 2,000 feet, broken clouds at 4,000 feet. Outlook, marginal VFR due to mist and ceilings.
Example:
NE…UPDT SCT050-070. 01Z SCT CI TO SKC. OTLK...VFR.
If the letters “UPDT” appear after a particular geographic area, the forecast for that area has been amended or corrected.