Evaluation of ESTOFEX forecasts: Severe thunderstorm forecasts

Over the past few years, an informal group of European meteorologists have forecast convective weather as part of the European Storm Forecast Experiment (ESTOFEX-http://estofex.org). The forecasts are intended to resemble the US NWS Storm Prediction Center convective outlooks, with a general thunder forecast and levels of severe thunderstorm (hail, wind gusts, or tornado) threat.

As part of a class project in a graduate course in Forecast Evaluation and Decision Analysis at the University of Oklahoma, ESTOFEX forecasts from 30 April 2006 to December 2007 were analyzed. There are over 500 forecasts considered.

Here, we report on the results of the severe thunderstorm forecasts. Reports from the European Severe Weather Database (ESWD-http://www.essl.org/eswd) are used for the observations. In general, increasing threat levels are associated with greater probability of severe thunderstorm occurrence. Differences between the forecasters, particularly in terms of areal coverage of forecasts, are apparent. Challenges in using the ESWD database are also discussed.

In a companion presentation, we report on the general thunder forecasts.