How to Read a GAF (Graphical Area Forecast)

The Graphical Area Forecast, or GAF, is the Bureau of Meteorology forecast of weather from the surface to 10,000 ft for a defined area. It replaced the text-only ARFOR in 2018. Each issue is a chart showing area boundaries plus a table describing the weather inside each area, and it always carries a printed validity period — only use a GAF that is valid for your whole flight.

The two parts of a GAF

The chart panel divides the region into areas drawn as boxes and labelled A, B, C and so on. The boundaries follow weather features, so they move from issue to issue.

The table lists, for each area: cloud amount and type with base and top, visibility and weather, and any freezing level, icing or turbulence. Hazards such as cumulonimbus and thunderstorms are called out in their own boxes.

Reading the entries

Every height on a GAF is above mean sea level, not above ground level.

• SCT CU 3000/8000 — scattered cumulus, base 3000 ft AMSL, tops 8000 ft AMSL.
• Visibility is given in metres or kilometres, with the cause (for example 6000 in HZ).
• A separate box lists CB, TS, moderate or greater turbulence, and airframe icing when forecast.
• A cumulonimbus forecast implies moderate or greater turbulence and icing, and possible hail — treat it as a hazard area.

Use it with the winds

The GAF does not contain wind and temperature aloft. Read it together with the Grid Point Wind and Temperature (GPWT) chart for the same area and validity to complete your flight plan.

Official sources

• Bureau of Meteorology — Graphical Area Forecast (GAF)
• Airservices Australia — Aeronautical Information Package (AIP)

Keep studying

• Meteorology (CMET) study guide →