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4.3 FM Group
The “FM” (From) change indicator group is used to sub-divide the forecast to indicate when prevailing conditions are expected to change significantly over a period of less than one (1) hour.
Important points on the use of the FM Group
- The FM indicator will be followed by all elements of the TAF such as surface wind, visibility, significant weather, clouds/obscurations, and when expected, non-convective Low Level Wind Shear (LLWS), regardless if they are forecast to change or not.
- The only exception to this involves significant weather. If no significant weather is expected in the FM time period, then significant weather is omitted.
- For clarity, each FM group starts on a new line and is indented 5 spaces from the left margin.
The contraction, FM, followed by six (6) digits which indicates the day of the month and the time (in hours and minutes UTC) that a change is expected. Whenever possible, forecasting changes to the minute is encouraged to provide better time resolution as to when the changes are expected.
Examples:
