This from the estofex website http://www.estofex.org/html/information.html before you all get to aggitated about tuesday
"How reliable are ESTOFEX forecasts? We have been running a verification of the lightning forecasts since 2006, see the Verification section for detailed information. Also, first verification efforts of the severe-weather forecasts have been realized in collaboration with the University of Oklahoma (see the literature page). While there is a lack of severe weather reports reaching us, a verification of the threat level areas has been started. Some results are presented in the new description of the threat levels. The probability of severe weather events indeed increases according to the forecast threat level. The probability of detection, based on reported events, inside at least a level 1 is: gusts: 57%, significant gusts: 81%, hail: 60%, significant hail: 84%, tornadoes: 36%, significant tornadoes: 67%. This shows that extremely severe events are less likely to be missed, but note that around 80% of extremely severe events did not fall inside the higher threat levels (2 and 3) which are considered most appropriate. There is room for improvement. More results will be presented at the European Conference on Severe Storms in October 2009. The quality of data is crucial for a more reliable verification. Please help us and other scientists: submit to the ESWD!"