Description and evaluation of the second generation Graphical Turbulence Guidance forecasting system

The first generation Graphical Turbulence Guidance (GTG) became “operational” in March 2003 for use by meteorologists as an aid to forecasting upper level turbulence areas over the continental U.S. GTG uses a combination of individual turbulence diagnostics derived from RUC forecasts weighted by comparisons to turbulence pilot reports. This technique of combining diagnostics has been shown to provide superior performance to the use of individual diagnostics in producing automated turbulence forecasts. Since the original GTG release (GTG1), development of the second generation GTG, GTG2, has been ongoing under sponsorship of the FAA AWRP. GTG2 includes several improvements over GTG1, including the use of new turbulence diagnostic algorithms, better thresholding of the individual diagnostics, and extension of forecasts to mid-levels (FL100-FL200). GTG2 is scheduled to become “operational” in early FY06. A technical description of the GTG2 product as well as statistical evaluations of GTG2 probability of detection performance is provided.