GFA – Icing, Turbulence and Freezing Level
General
The graphic area forecast (GFA) icing, turbulence and freezing level chart depicts forecast areas of icing and turbulence as well as the expected freezing level at a specific time. Included on the chart are the type, intensity, bases and tops of each icing and turbulence area. Surface synoptic features such as fronts and pressure centres are also shown. This chart is to be used in conjunction with the associated GFA clouds and weather chart issued for the same period of validity.
Icing
Depicted in blue whenever moderate 
or severe 
icing is forecast for the coverage area. The bases and tops of each icing layer, measured in hundreds of feet above mean sea level, as well as the type of icing. Areas of light icing are described in the comments box. An area of moderate mixed icing based at 2,000 ft ASL with a top of 13,000 ft ASL would be indicated as follows:
Freezing Level
Freezing level contours are indicated by dashed lines. The height of the freezing level is indicated to the nearest multiple of 2,500 ft. When more than one freezing level is forecast, only the lowest level needs to be indicated, unless meteorological conditions are expected to be relevant to aviation safety.
Turbulence
Depicted in red and indicated whenever moderate 
or severe 
turbulence is forecast for the coverage area. Severe turbulence is depicted with a higher density of hatching than areas of moderate turbulence. The cause of the turbulence will also be included. When separate areas of turbulence are occurring at different altitudes, the lower level is shown with hatching that slants upward to the right, while the higher level is depicted with hatching that slants downward to the right.
Low Level Jets
The presence of low-level jets (LLJs) are depicted on the GFA icing, turbulence and freezing level chart when it is expected to have a peak core speed of 50 kt or more, however, it may be included at speeds between 35 and 45 knots when significant associated turbulence or shear is expected.