All about TAFs!

What's a TAF?

• Terminal Aerodrome Forecast (TAF)

• The code format for expected meteorological conditions within a 5 SM radius from the center of an airport’s runway complex typically for the next 24 hours

• Developed for aviation weather

• Reported by every airport four times a day at 23:40, 06:40, 11:40 and 17:40 UTC

Example:

TAF KJFK 162005Z 1620/1724 29015G24KT P6SM SCT035

  FM162300 28010G18KT P6SM FEW035

  FM170000 28010KT P6SM FEW240

  FM171500 27014G22KT P6SM SCT045

Similarities to METARs

TAF KCDC 161836Z 1619/1718 35012G20KT P6SM -SHSN OVC020

• Four-letter Station ID

• Date & Time

• Wind

• Visibility

• Present Weather

• Clouds

Types of Reports

TAF KCDC 161836Z 1619/1718 35012G20KT P6SM -SHSN OVC020

2 types of reports:

• TAF: standard report at standard time

• TAF AMD: Issued when the current TAF no longer adequately describes the ongoing weather, or forecasters feel the TAF isn’t representative of the current or expected weather

Valid Period Date and Time

TAF KCDC 161836Z 1619/1718 35012G20KT P6SM -SHSN OVC020

• The UTC valid period of the forecast is the beginning date & hour and the ending date & hour

  • • Valid periods beginning at 00:00 UTC are indicated as 00

    • Valid periods ending at 00:00 UTC are indicated as 24

• If a forecast is amended, corrected, or delayed, the valid period may be for less than 24 hours

• The TAF is valid until a new TAF is issued

• NIL means the TAFs were issued when the location was closed

• NIL AMD SKED AFT (closing time) Z is added to the end of the forecast if the location is operated on a part-time basis (not 24 hours)

Wind

TAF KCDC 161836Z 1619/1718 VRB12G20KT P6SM -SHSN OVC020

• Variations in wind direction can be reported as: "VRB"

  • Replaces the wind direction, as it is impossible to forecast the wind direction due to convective activity or low wind speeds

Visibility

TAF KCDC 161836Z 1619/1718 35012G20KT P6SM -SHSN OVC020

• The only difference between METARs and TAFs regarding visibility is a potential  “P”

• A “P” before indicates that the visibility is more than six statute miles

Optional Data - Wind Shear

TAF KCDC 161836Z 1619/1718 35012G20KT P6SM -SHSN OVC020 WS020/07040KT

• Wind shear (WS) is the forecast of non-convective low-level winds (up to 2000 feet) above the surface

• Follows the sky conditions category if it is expected

• Includes the height of the new wind followed by the wind direction and wind speed at the indicated height

• The height of the wind is in hundreds of feet AGL up to 2,000 feet

  • • Example above: wind at 2,000 ft AGL with a wind direction of 70º and a 40-knot wind

Additional Lines

TAF KCDC 161836Z 1619/1718 35012G20KT P6SM –SHSN OVC020 

LINE 1706/1709 CONDITIONS THAT CHANGE

• There are four types of additional lines: PROBABILITY, FROM, BECOMING, & TEMPORARY

• The first two digits are the date and the last two digits are the beginning hour and ending hour of the change period

• The four digits in a FROM after the date are the hour and minute where the change is expected to begin

  • • Conditions that can change are winds, visibility, weather, and sky condition

    • The omitted conditions are carried over from the previous time group

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