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specified time and to persist until the end of the validity periodof the TTF
or until newmean conditions are given;
• Intermittent variations (for periods less than 30minutes) and temporary
variations (for periods of 30minutes ormorebut less than60minutes) are
given as INTER andTEMPO respectively, followedby the validity period in
the format hhmm/hhmmwhereh= hour andm=minuteUTC; and
• Moderate or severe low-level turbulence excludes turbulence associated
with convectiveweather. TILL (time) is used if the turbulence is expected
to cease before the end validity period of theTREND.
TheTTF supersedes the TAF for its validity period and is the current forecast
for pilots of aircraftwhose arrival time fallswithin the validity period. For
aerodromeswhere the TTF service is not a 24 hour service, theTAFwill
become the valid forecast from the time indicated in the remarks section of
the TTF e.g. USE TAF FORARRIVALAFTER 0800Z.
Note: For pilotswhose arrival time falls outside the three-hour period, the TAF
is the current forecast.Where applicable, TTF replaces TAF and present
weather inVOLMET broadcasts.
TrendForecast (TTF)Examples
TTFSPECI YPAD 012200Z 00000KT 5000DZOVC00514/14Q1025RMK
RF00.4/000.4
FM2200 00000KT 9999NSWBKN008 FM2300 03005KT 9999NSWSCT020
TTFSPECI YMML 100200Z 05008KT 4000DZBKN005OVC100 16/15Q1017
RMKRF00.2/000.2
NOSIG
TTFMETARYPPH 120500Z 36015KTCAVOK 32/08Q1014RMK
RF00.0/000.0
FM0630 28025KT 9999NSWBKN030 INTER0530/0730 5000SHRA
BKN008
TTFMETARYBTL 220730Z 35006KT 9999FEW050TCU 31/21Q1005 RMK
RF00.0/000.0DISTANT THUNDER
NOSIG
TTFSPECI YBTL 240800Z 03010KT 4000 TSRABKN030CBSCT120 27/24
Q1008RMKRF00.0/000.0
FM0830 03005KT 9999SHRABKN035
INTER 0830/1100 4000 TSRASCT010SCT030CB
trend forecast