Graphic area forecast (GFA)

The GFA (graphic area forecast) is the picture of expected weather at or below 24,000 ft ASL over a region, drawn for pre-flight planning.

Each valid time has two charts:

• Clouds and weather: cloud bases and tops, visibility, weather and obstructions to vision.

• Icing, turbulence and freezing level: the areas of icing and turbulence (with bases and tops) and the forecast freezing level.

• Fronts and pressure systems are drawn on both charts, so each can be read on its own.

• Issued four times a day, valid 0000, 0600, 1200, 1800Z, for seven regions.

• Each is valid 12 hours, with a further 12-hour IFR outlook in the comments box of the final clouds and weather chart.

• A SIGMET or AIRMET automatically amends the GFA in force.

• Heights are ASL, wind in knots, visibility in SM, times in UTC.

Trap: looking for icing or the freezing level on the clouds and weather chart. Those live on the second chart (icing, turbulence and freezing level).

Practice