Studies in forecasting upper-level turbulence

Abstract

Encounters with turbulence generated by complex topography, convection, or mechanical forcing present a significant threat to military aircraft operations. Properly forecasting the initiation, duration, and intensity of such encounters is a tremendous challenge to forecasters often resulting in the over-forecasting of turbulence. Over-forecasting the presence or intensity of turbulence can result in unnecessary mission delays, cancellations, and re-routing. The lack of observations and the fact that turbulence is a microscale phenomenon which Numerical Weather Prediction (NWP) models currently can not resolve are what make forecasting turbulence so difficult. Progress has been made in the last several decades in both the observation of turbulence and the resolution of NWP models. A new turbulence forecast approach has been created based on recent developments in observing turbulence and using automated turbulence diagnostics. The development of an in-situ observation platform, using the Eddy Dissipation Rate (EDR), and the Graphical Turbulence Guidance (GTG) model are discussed. A turbulence forecast approach is derived that includes the synoptic patterns which create or allow the turbulent environment to exist, the use of current tools to observe turbulence, and the use of models to help form the turbulence forecast. A turbulence forecasting manual has been created to give the new forecaster improved guidance to effectively forecast turbulence.