Note:  The following changes will be effective November 5th, 2008,
beginning with the 00 UTC TAF package

Quick jumps on this page:

1.  Background

The International Civil Aviation Organization (ICAO) Annex 3, "Meteorological Service for International Air Navigation", was updated at the request of long-haul carriers to include a provision for a 30 hour TAF.  In order to accommodate this change, the TAF format was updated to include the date with every time reference. The National Weather Service will change to the new TAF format beginning with the 00 UTC TAF issuance on November 5th, 2008.

With the new format, the National Weather Service will begin issuing 30 hour TAF's for 32 airports across the country.  (However, all NWS TAF's will change to the new format.)  In Hawaii, Honolulu International Airport (PHNL) is the only airport going to a 30 hour TAF.  The complete list of NWS TAF sites changing to the 30 hour duration is located in Appendix 1

2.  Format Changes

Every time reference in the TAF will now have date included with it.  For example:

Old Format New Format
FMhhmm FMddhhmm
TEMPO hhhh TEMPO ddhh/ddhh
AMD NOT SKED AFT hhZ AMD NOT SKED AFT ddhhmm

Where:

The rules regarding the differences between 00Z and 24Z remain the same.  "00" is used for the beginning of a time group, and "24" is used for the end of a time group.  For example:

Old Format New Format
FM0000 FM010000
TEMPO 0004
TEMPO 2024
TEMPO 0100/0104
TEMPO 0120/0124
AMD NOT SKED AFT 00Z
AMD NOT SKED TIL 24Z
AMD NOT SKED AFT 010000
AMD NOT SKED TIL 012400

3.  Examples

The following are examples of the new TAF format.  Differences from the old format are highlighted.

Example of a 30 hour TAF with TEMPO groups:

TAF
PHNL 051730Z 0518/0624 20018G25KT P6SM SCT020 BKN035
FM052100 24020G30KT 3SM SHRA BR BKN025 OVC040
TEMPO 0521/0523 2SM TSRA BKN018CB
FM052300 28020G35KT P6SM –SHRA SCT020 BKN040
TEMPO 0523/0602 5SM SHRA BKN020
FM061200 26015G25KT P6SM SCT025 BKN060
FM062000 23015KT P6SM VCSH SCT025 BKN045=

Example of the new "AMD NOT SKED" format:

TAF
PHJH 102330Z 1100/1124 06015G25KT P6SM FEW030 SCT050
FM110500 08012KT P6SM FEW030
FM112100 06015G25KT P6SM FEW030 SCT050
AMD NOT SKED AFT 110400=

Appendix 1

The following NWS TAF's will change to a 30 hour TAF beginning November 5th, 2008:

KATL Atlanta Intl
KBDL Bradley Intl
KBOS Logan Intl
KBWI Baltimore-Washington Intl
KCLE Cleveland Hopkins Intl
KCVG Covington/Cincinnati
KDEN Denver Intl
KDFW Dallas/Fort Worth Intl
KDTW Detroit
KEWR Newark Liberty Intl
KIAD Washington Dulles Intl
KIAH Houston - George Bush Intl
KIND Indianapolis Intl
KJFK John F. Kennedy Intl
KLAX Los Angeles Intl
KMKE General Mitchell Intl
KMSP Minneapolis-St Paul Intl
KOAK Oakland Intl
KONT Ontario Intl
KORD Chicago-O’Hare Intl
KPHL Philadelphia Intl
KPIT Pittsburgh Intl
KSAN San Diego Intl
KSDF Louisville Intl
KSEA Seattle-Tacoma Intl
KSFO San Francisco Intl
KSLC Salt Lake City Intl
KSTL Lambert-St Louis Intl
KSWF Stewart Intl
PAFA Fairbanks Intl
PANC Anchorage Intl
PHNL Honolulu Intl