GM1 MET.TR.220(f)(1) Aerodrome forecasts
TAF — USE OF CHANGE AND TIME INDICATORS
Guidance on the use of change and time indicators in TAF is given below:
|
Change or time
indicator |
Time period |
Meaning |
||
|
FM |
|
ndndnhnhnmnm |
Used to indicate a significant change in most weather elements occurring at ndnd day, nhnh hours and nmnm minutes (UTC); All the elements given before ‘FM’ are to be included following ‘FM’ (i.e. they are all superseded by those following the abbreviation). |
|
|
BECMG |
|
nd1nd1nh1nh1/nd2nd2nh2nh2 |
The change is forecast to commence at nd1nd1 day and nh1nh1 hours (UTC) and be completed by nd2nd2 day and nh2nh2 hours (UTC); Only those elements for which a change is forecast are to be given following ‘BECMG’; The time period nd1nd1nh1nh1/nd2nd2nh2nh2 should normally be less than 2 hours and in any case should not exceed 4 hours. |
|
|
TEMPO |
|
nd1nd1nh1nh1/nd2nd2nh2nh2 |
Temporary fluctuations are forecast to commence at nd1nd1 day and nh1nh1 hours (UTC) and cease by nd2nd2 day and nh2nh2 hours (UTC); Only those elements for which fluctuations are forecast are to be given following ‘TEMPO’; temporary fluctuations should last less than 1 hour in each instance, and in the aggregate, cover less than half of the period nd1nd1nh1nh1/nd2nd2nh2nh2. |
|
|
PROBnn |
— |
nd1nd1nh1nh1/nd2nd2nh2nh2 |
Probability of occurrence (in %) of an alternative value of a forecast element or elements; nn = 30 or nn = 40 only; To be placed after the element(s) concerned. |
— |
|
TEMPO |
nd1nd1nh1nh1/nd2nd2nh2nh2 |
Probability of occurrence of temporary fluctuations. |
||
EASA aviation regulations define aerodrome forecast (TAF) change indicators. "FM" signifies a complete weather change at a specific time. "BECMG" indicates a change occurring within a 2-4 hour window. "TEMPO" forecasts temporary fluctuations. "PROBnn" expresses the probability (30/40%) of alternative conditions. These indicators are crucial for flight planning and safety.
* Summary by Aviation.Bot - Always consult the original document for the most accurate information.
Loading collections...