Including convection in global turbulence forecasts

The World Area Forecast Centres provide aviation users around the world with meteorological hazard forecasts. At present, hazard forecasts are issued for turbulence associated with wind shear or mountain waves. However convection is also a major source of turbulence. This paper proposes a method for combining different predictors of turbulence derived from the area of biostatistics, and this is used to produce a single global turbulence forecast that includes convection as well as wind shear and mountain-wave components. The use of the Richardson number and a climatology of observed turbulence are also investigated as a way of improving turbulence forecasts. The performance of the forecast is tested using an objective verification scheme using automated aircraft observations, and it is shown that the inclusion of convective indicators, as well as Richardson number and climatology, can greatly improve the skill in forecasting turbulence. Copyright © 2012 British Crown Copyright, the Met Office. Published by John Wiley & Sons Ltd.

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