Probabilistic high-resolution forecast of heavy precipitation over Central Europe

C. Marsigli (1) , A. Montani (1) , F. Nerozzi (1) , T. Paccagnella (1)

1 ARPA-SIM

The limited-area ensemble prediction system COSMO-LEPS has been running operationally at ECMWF since November 2002. Five runs of the non-hydrostatic limited-area model Lokal Modell (LM) are available every day, nested on five selected members of three consecutive 12-h lagged ECMWF global ensembles. The limited-area ensemble forecasts range up to 120h and LM-based probabilistic products are disseminated to several national weather services. COSMO-LEPS has been constructed in order to have a probabilistic system with high resolution, focussing the attention on extreme events in regions with complex orography. In this paper, the performance of COSMO-LEPS for a heavy precipitation event that affected Central Europe in August 2002 has been examined. At the 4-day forecast range, the probability maps indicate the possibility of the overcoming of high precipitation thresholds (up to 150mm/24h) over the region actually affected by the flood. Furthermore, one out of the five ensemble members predicts 4 days ahead a precipitation structure very similar to the observed one.

Domaines: Interfaces continentales, environnement; Océan, Atmosphère; Sciences de la Terre

C. Marsigli, A. Montani, F. Nerozzi, T. Paccagnella. Probabilistic high-resolution forecast of heavy precipitation over Central Europe. Natural Hazards and Earth System Sciences, 2004, 4 (2), pp.315-322. ⟨hal-00299120⟩