AIM

4/20/23

7

−

1

−

75

Meteorology

28024G36KT

wind two eight zero at two four gusts three six

. .

3/4SM

visibility three fourths

. . . . . . . .

+TSRA

thunderstorms, heavy rain

. . . . . . .

BKN008

ceiling eight hundred broken

OVC020CB

two thousand overcast cumulonimbus clouds

. . .

28/23

temperature two eight, dew point two three

. . . . . . . . .

A3000

altimeter three zero zero zero

. . . . . . . .

RMK

remarks 

. . . . . . . .

TSRAB24

thunderstorm and rain began at two four

. . . . .

TS W MOV E

thunderstorm west moving east

c. Aerodrome Forecast (TAF).

A concise statement of the expected meteorological conditions at an airport

during a specified period. At most locations, TAFs have a 24 hour forecast period. However, TAFs for some
locations have a 30 hour forecast period. These forecast periods may be shorter in the case of an amended TAF.
TAFs use the same codes as METAR weather reports. They are scheduled four times daily for 24

−

hour periods

beginning at 0000Z, 0600Z, 1200Z, and 1800Z.

Forecast times in the TAF are depicted in two ways. The first is a 6

−

digit number to indicate a specific point in

time, consisting of a two

−

digit date, two

−

digit hour, and two

−

digit minute (such as issuance time or FM). The

second is a pair of four

−

digit numbers separated by a “/” to indicate

 

a beginning and end for a period of time.

In this

 

case,

 

each four

−

digit pair consists of a two

−

digit date and a two

−

digit hour.

TAFs are issued in the following format:

TYPE OF REPORT/ICAO STATION IDENTIFIER/DATE AND TIME OF ORIGIN/VALID PERIOD DATE
AND TIME/FORECAST METEOROLOGICAL CONDITIONS

NOTE

−

The “/” above and in the following descriptions are for separation purposes in this publication and do not appear in the
actual TAFs.

TAF KORD 051130Z 0512/0618 14008KT 5SM BR BKN030 

TEMPO 0513/0516 1 1/2SM BR
FM051600 16010KT P6SM SKC
FM052300 20013G20KT 4SM SHRA OVC020
PROB40 0600/0606 2SM TSRA OVC008CB 
BECMG 0606/0608 21015KT P6SM NSW SCT040

TAF format observed in the above example:

TAF = type of report

KORD = ICAO station identifier

051130Z = date and time of origin (issuance time)

0512/0618 = valid period date and times

14008KT 5SM BR BKN030 = forecast meteorological conditions

Explanation of TAF elements:

1. Type of Report.

There are two types of TAF issuances, a routine forecast issuance (TAF) and an

amended forecast (TAF AMD). An amended TAF is issued when the current TAF no longer adequately describes
the on-going weather or the forecaster feels the TAF is not representative of the current or expected weather.
Corrected (COR) or delayed (RTD) TAFs are identified only in the communications header which precedes the
actual forecasts.

2. ICAO Station Identifier.

The TAF code uses ICAO 4

−

letter location identifiers as described in the

METAR section.