In trend forecasts, what does 'BECMG' indicate and how are the start and end times specified?

'BECMG' indicates that a change is forecast to commence at n1n1n1n1 UTC and be completed by n2n2n2n2 UTC.

What does 'FMnnnn' mean as a time indicator in trend forecasts?

It means the change will commence at nnnn UTC and be completed by the end of the trend forecast period.

'TEMPO' indicates that temporary fluctuations are forecast.

It signifies that the change will commence at the beginning of the trend forecast period and be completed by nnnn UTC.

No significant changes are forecast.

The period commences at the beginning of the trend forecast period and is completed by the end of the trend forecast period.

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GM1 MET.TR.225(c)(7)(ii) Forecasts for landing

ED Decision 2022/004/R

TREND FORECASTS — USE OF CHANGE INDICATORS

Guidance on the use of change indicators in trend forecasts is given in the table below.

Change indicator	Time indicator and period	Meaning
NOSIG	—	no significant changes are forecast
BECMG	FMn₁n₁n₁n₁ TLn₂n₂n₂n₂	the change is forecast to	commence at n₁n₁n₁n₁ UTC and be completed by n₂n₂n₂n₂ UTC
	TLnnnn		commence at the beginning of the trend forecast period and be completed by nnnn UTC
	FMnnnn		commence at nnnn UTC and be completed by the end of the trend forecast period
	ATnnnn		occur at nnnn UTC (specified time)
	—		commence at the beginning of the trend forecast period and be completed by the end of the trend forecast period; or the time is uncertain
TEMPO	FMn₁n₁n₁n₁ TLn₂n₂n₂n₂	temporary fluctuations are forecast to	commence at n₁n₁n₁n₁ UTC and cease by n₂n₂n₂n₂ UTC
	TLnnnn		commence at the beginning of the trend forecast period and cease by nnnn UTC
	FMnnnn		commence at nnnn UTC and cease by the end of the trend forecast period
	—		commence at the beginning of the trend forecast period and cease by the end of the trend forecast period

Source-Title: GM1 MET.TR.225(c)(7)(ii) Forecasts for landing View latest amendments

Erulesid: ERULES-1963177438-3488 Compare versions

Domain: Air traffic management/Air navigation services

Activitytype: Meteorological services (MET)

Amendedby: Initial issue

Applicabilitydate: 13 June, 2022

Entryintoforcedate: 15 March, 2022

Icaoreference: Annex 3

Regulatedentity: MET provider

Regulatorysource: ED Decision 2022/004/R Navigate

Regulatorysubject: Part-MET

Typeofcontent: GM to IR (Guidance material to implementing rule)

Parentir: MET.TR.225 Forecasts for landing

Origin: EASA

Category: EAR