Terminal Aerodrome Forecast (TAF) Format to Change November 5, 2008

On November 5, 2008, a change in the Terminal Aerodrome Forecast (TAF) will occur that introduces a date/time element to the body of the TAF to include the change groups for all TAFs issued by the National Weather Service.  This change in format is necessary to meet the service requirements as defined by the International Civil Aviation Organization (ICAO) to provide a 30-hour TAF. 

A 30-hour TAF is needed to support flight planning requirements for long-haul flights.  With the longer range and cruising time of the newer aircraft, the airlines with long-range international flights have found themselves dispatching flights that land beyond the 24-hour TAF valid period.  They are not able to plan fuel or alternates per FAA rules.  

In the United States it has been determined that 32 airports meet the requirements for a 30-hour TAF.  For the western United States these airports are:  Los Angeles International, Metropolitan Oakland International, Ontario International, San Diego International, Seattle-Tacoma International, San Francisco International, and Salt Lake International. 

The TAFs issued for Jack McNamara Field (Crescent City), Eureka/Arcata Airport and Ukiah Municipal Airport will remain 24-hour TAFs.  However, these TAFs will be issued in the new format beginning November 5, 2008 at 0000 UTC.

For safety purposes, it was decided that all TAFs should adhere to a generic format regardless of the valid period of the TAF. So the TAFs remaining at 24 hours will also incorporate a date/time element in the body of the TAF as well as the change groups:  FM (from), TEMPO, and PROB.

Comparison of the current and new 24-hour aerodrome forecast formats:

Example of a 30-hour TAF:

TAF

KSFO 181130Z 1812/1918 08008KT P6SM SCT070 BKN250
     FM182000 12008KT P6SM BKN150
      TEMPO 1822/1902 BKN070
     FM190200 15005KT P6SM BKN050 OVC100
       PROB30 1906/1910 12010KT P6SM FEW005 OVC025
     FM191500 32007KT P6SM SKC

So in the above example…

            - KSFO is the identifier for San Francisco International Airport.

            - In the first line of the example, the TAF was issued by the NWS San Francisco office at 1130Z on the
              18th. 18121918 means the forecast is valid the 18th at 1200 UTC through the 19th at 1800 UTC.

            - In the second line the FROM group is valid the 18th at 2000 UTC.

            - In the third line the TEMPO group is valid the 18th at 2200 UTC through the 19th at 0200 UTC.

            - In the 4th line the FROM group is valid the 19th at 0200 UTC.

            - In the 5th line the PROB group is valid the 19th 0600 UTC through the 19th at 1000 UTC

            - In the 6th line the FROM group is valid the 19th at 1500 UTC.

Remember that on November 5, 2008 a new TAF code format will be put in place.  This new format will provide the aviation community a date/time element in the body and the change groups in the TAF.  The first TAF to use this new format will be the TAF valid starting at 0000 UTC on November 5, 2008.

Send any questions on this change to:  Brian.Koeneke@noaa.gov

FLY SAFE!!

Brian Koeneke
Aviation Focal Point
WFO Eureka