The international aviation community has expressed a desire for forecasts of turbulence (and other hazards) to be produced in the form of gridded numerical data in the future. In response the Met Office has developed a system that will produce global forecasts of clear air turbulence (CAT) in numerical format. These forecasts extend up to 36 hours ahead and are used primarily for flight planning. The system uses Ellrod's TI1 index to predict CAT caused by wind shear and an algorithm to forecast mountain wave turbulence based on gravity wave stresses. The skill of the shear induced CAT forecasts was evaluated using aircraft observations from our database of categorised turbulent events.

Of course there is always scope for forecast improvement. Therefore we are currently investigating the possibility of using our “WAFTAGE” wind and temperature nowcasting tool to produce CAT forecasts over the North Atlantic area. If successful, these forecasts will typically be of the order of an hour (or less) ahead and will be used as part of the FLYSAFE project to provide warnings to aircraft in flight.