Forecast expert: DWD issued the first warning information on Monday
In the case of the severe storms in western Germany last week, the computer models of the German Weather Service (DWD) already gave clear indications on Monday. “We were able to publish the advance information on Monday, which already stated that up to 200 liters (precipitation per square meter) are expected”, said Franz-Josef Molé, the head of the forecast and advice center of the German Weather Service (DWD), the German press agency. “It didn’t really work before.”
The forecasting experts collaborated about 100 different simulations of their different calculation models – “and in principle most of them were fairly certain to target western Germany for the period from Wednesday to Thursday night.”
That is so unusual, as precise warnings in the event of storms with extreme rain are usually extremely difficult: Most of the time, the events involved are small-scale and very dynamic. “A completely different area can be affected within half an hour than shown in the models – that makes the whole thing so difficult,” said Molé.
In the case of the storm in the night from Wednesday to Thursday, the DWD experts would have “already marked a large region on Monday and also recorded these extreme amounts,” emphasized Molé. “We not only warned of heavy rain, but of continuous rain. Usually the water boards realize that this is the worst situation one can have in summer – heavy rainfall embedded in a permanent rain area. “
Could anyone have any idea how badly the storms would actually hit the affected regions? “In that case, the amount of precipitation was so exorbitantly high that the places could not actually have been protected,” said Molé.
With increasingly better computer models and data volumes, according to DWD, a lot has already happened to make predictions even more precise. Molé could not rule out that with the same weather situation with a low pressure area from the Mediterranean region, a similarly threatening storm could again occur. “Overall, the air mass is warmer than it was decades ago – and warmer air can absorb more moisture,” he said. “And if warm air is brought in from the Mediterranean in such a weather situation, then it rains more heavily.” (Dpa)