Short-Term Storm Forecasting from Blending Satellite-Based Extrapolation Forecasts with NWP Model Outputs over the Gulf of Mexico

Convection over the ocean poses a potentially great danger for trans-oceanic flights, as tragically demonstrated in the Air France 447 accident of 2009. This paper describes a forecasting system that will produce 0-12 hr convective forecasts over the Gulf of Mexico domain using a blending technique that combines satellite-based extrapolating forecasts with Numerical Weather Prediction (NWP) model forecasts.

Closely following the steps of the Federal Aviation Administration (FAA) Aviation Weather Research Program (AWRP) CoSPA development, a forecasting system is being developed to blend satellite-derived rain rate and cloud top height with their corresponding fields derived from the Global Forecasting System (GFS) NWP model. Forecasts will be computed over the 0-12 hr time frame within a domain that encompasses the greater Gulf of Mexico. Considering the relative strength of the NWP model and the satellite-based extrapolating forecasts, a weighted-average technique, similar to what is being used in CoSPA, is being tested. The weights are determined by historical performance of extrapolation and model forecasts as a function of forecast lead time. Tests of various extrapolation techniques have been completed and an optimum technique has been selected. GFS rain rate forecast performance statistics are being compiled. Preliminary results of a proto-type blended forecasting system for oceanic convection will be reported at the conference.