Global Turbulence Forecasts for Aviation

A forecasting system for aviation turbulence is described which uses a global NWP model or models (e.g., GFS, UKMet Office, ECMWF) to derive an “ensemble” of turbulence “diagnostics”. These diagnostics can be combined into a final forecast in the manner of the FAA-sponsored Graphical Turbulence Guidance (GTG) product. Focus is on upper-level turbulence forecasts primarily for commercial aviation and includes explicit diagnostics for both clear-air turbulence sources and mountain-wave turbulence sources, and also implicitly provide indications of convective cloud-induced turbulence for larger cloud systems. The forecasts provided are in terms of the energy dissipation rate^1/3 (EDR), which is an aircraft-independent metric of turbulence. The forecast methodology is described and some example cases and statistical analyses are provided as verification for a GFS-based system.