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Decoding Aerodrome Forecast (TAF)

A TAF conveys the following meteorological information:

Originating airport name, TAF validity period, wind direction/speed/gust, visibility, weather, cloud, maximum and minimum temperature, significant change of weather elements.

Visibility : 9999 = 10 km or above, 7000 = 7 km, 0000= less than 50 m
              CAVOK = sky and visibility OK

Weather : - = light, + = heavy, VC = vicinity, MI = shallow, BC = patches,
              SH = showers, PR = partial, TS = thunder storms,
              DZ = drizzle, RA = rain, BR = mist, FG = fog, HZ = haze,
              +SHRA = heavy showers of rain
              -DZ = light drizzle

Cloud : cloud amount given in eighths of sky (oktas) covered where
            FEW = 1 to 2 oktas, SCT = 3 to 4 oktas, BKN = 5 to 7 oktas,
            OVC = 8 oktas and SKC = sky clear

Significant change : BECMG = becoming, TEMPO = temporarily

When forecast temperatures are included in accordance with regional air navigation agreement, the maximum and minimum temperatures expected to occur during the period of validity of the aerodrome forecast should be given, together with their corresponding times of occurrence.  If there are two forecast maxima or mimima of equal values, the first occurrence time would be given.

An amended forecast may be issued subject to certain criteria and is prefixed by the keyword TAF AMD.

Example :

TAF VHHH 160500Z 1606/1712 13018KT 9000 BKN020 TX30/1606Z TN26/1622Z BECMG 1606/1608
SCT015CB BKN020 TEMPO 1608/1612 17025G40KT 1000 TSRA SCT010CB
BKN020 FM161200 15015KT 9999 NSW BKN020 BKN100=

Decoded as :
 

CODE MEANING
TAF VHHH TAF issued by the Hong Kong International Airport
160500Z on the 16th of the month at 0500 UTC
1606/1712 valid from 0600 UTC to 1200 UTC the next day
13018KT surface wind direction 130 degree (east-southeasterly winds); wind speed 18 knots
9000 visibility 9 km
BKN020 broken cloud at 2000 feet
TX30/1606Z maximum temperature 30 oC occurred around 0600 UTC, 16th
TN26/1622Z minimum temperature 26 oC occurred around 2200 UTC, 16th
BECMG 1606/1608 SCT015CB BKN020 becoming between 0600 UTC to 0800 UTC, scattered cloud at 1500 feet including cumulonimbus cloud and broken cloud at 2000 feet
TEMPO 1608/1612 17025G40KT 1000 TSRA SCT010CB BKN020 temporarily between 0800 UTC and 1200 UTC surface wind direction 170 degree (south-southeasterly winds); wind speed 25 knots gusting to 40 knots; visibility 1000 m in thunderstorm with moderate rain; scattered cloud at 1000 feet including cumulonimbus cloud and broken cloud at 2000 feet
FM161200 15015KT 9999 NSW BKN020 BKN100 from 1200 UTC surface wind direction 150 degree (south-southeasterly winds); wind speed 15 knots; visibility 10 km or above; nil significant weather; broken cloud at 2000 feet and broken cloud at 10000 feet