• The new Graphical Area Forecast (GAF) that went live on 9 November, 2017. (from AvPlan)
    The new Graphical Area Forecast (GAF) that went live on 9 November, 2017. (from AvPlan)

The Bureau of Meteorology (BOM) and Airservices Australia have now made live the new low-level Graphical Area Forecasts (GAF), superceding the old Area Forecast (ARFOR) for data below 10,000 feet.

The GAFs present weather information in graphical form rather than the stream of text abbreviations that have served the aviation industry for many decades. The changes apply to only the area weather; Terminal Area Forecasts (TAF) remain the same.

Previously, ARFORs were presented covering 28 areas, whereas there are only 10 GAFs available, aligned largely with the state boundaries. The GAFs present a clear pictorial of the area they cover and the forecast divisions the weather will refer to. This replaces the old system of interpreting divisions by reference to waypoints. Specific weather conditions new come in table divided into the nominated weather divisions.

Accompanying the GAFs are Grid Point Wind and Temperature charts (GPWT). GPWTs have been in use for higher altitudes for some time, and the system has now been applied to below 10,000 feet as well. The GPWT enables a user to select winds and temperatures from a grid overlaid on the GAF area according to cruise height, which is expected to make it easier to calculate ground speeds more accurately.

Forecast times and validity have also changed. The old ARFORs were issued every three hours with a validity of 12 hours, whereas the GAFs will come out every six hours, but be valid only until the next forecast comes out, i.e., for six hours only.

Australian Flying's Andrew Andersen was on the working group that established the GAFs, so naturally is a big supporter of the change.

"GAFs are much easier to read and interpret," he says, "and more comprehensive than ARFOR, a change that will improve safety for all GA pilots.

"All pilots need to learn about the GAF, whether self-taught or by attending a seminar. A little time now, before you next fly, will save a lot of frustration later on."

GAF training material is available on the BOM website.



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