First-Guess Early Warnings project Report on the Verification System
Mylne [K.R.] ; Legg [T.P.]
The First-Guess Early Warning (FGEW) project is aimed at giving NMC forecasters timely probabilistic guidance on the occurrence of severe weather events, in support of National Severe Weather Warning Service early warnings. FGEW output is based on forecast data from the ECMWF Ensemble Prediction System (EPS). Model event thresholds have been adjusted based on data from winter 2000/01 to optimise the system. This report gives skill assessments of warnings generated by the FGEW software, before and after optimisation, compared to warnings issued by NMC forecasters, using a variety of verification measures. The EPS data have greatest skill at 4 days ahead and have only a very limited ability at 1-3 days ahead to discriminate between high and low probabilities. NMC forecasters' warnings are skilful up to 2 days ahead but the FGEW system is capable of providing forecasters with useful guidance 4 days ahead. This should encourage the issue of Early Warnings longer in advance of severe events, thus fulfilling one of the aims of the project.
Accès à la notice sur le site du portail documentaire de Météo-France