Subject: New 30 hour Terminal Aerodrome Forecast (TAF) Format
This is a reminder to all users that the TAF code will be changing in November, 2008. With the addition of amendment 74 to Annex 3, the International Civilian Aviation Organization (ICAO) made provisions for a 30 hour TAF. This was in response to requirements by long haul operations. Although this will change the TAF coding for all TAFs worldwide, most TAFs will remain 24 hour forecasts. In California, KLAX, KSFO and KOAK are the only California airports that will expand to 30 hour period TAFs this year.
Meteorological users should ensure they are prepared ahead of time to account for changes to software, publications and training. This change will become effective at 18Z on 5 Nov 2008.
Below are two examples highlighting the new date/time group. The first example highlights the new 30 hour TAF format while the second example highlights a typical 24 hour TAF with the new format standard.
Typical US TAF using the new 30 hour period TAF for KOAK (Oakland International Airport).
It includes the period from 00-06 UTC on the 17th:
Meaning of the forecast:
Line 1: TAF for Oakland, CA issued on the 15th of the month at 2335 UTC valid from the 16th 0000 UTC to the 17th 0600 UTC; surface wind direction 180 degrees; wind speed 9 knots; visibility greater than 6 statute miles, sky condition broken at 2500 feet.
Line 2: Temporarily between 0800 UTC on the 16th and 1200 UTC on the 16th…surface wind direction 210 degrees; wind speed 15 knots gusting to 25 knots; visibility 3mile with light rain; sky condition with broken clouds at 1000 feet and overcast clouds at 2000 feet.
Line 3: From 0100 UTC on the 17th…the surface wind direction 150 degrees; wind speed 10 knots; visibility greater than 6 statute miles; and broken clouds at 2000 feet.
Typical US TAF using the new format with a 24 hour period TAF for KSMF (Sacramento International Airport). It does not include information from 00-06 UTC on the 17th:
Although this change to the TAF code is not complicated, there will be some effort by providers and users to adapt software to decode the new format, and ensure publications and training remain current.
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