Partitioning of snowy and rainy precipitation in a case of a north Adriatic frontal passage

M. Monai (1) , A. M. Rossa (1) , A. C. Bonan (1)

1 Meteorological Centre of Teolo

A case of snow fall in the plains of the Northern Italian region Veneto is presented from a forecasters' perspective. Contrasting forecast guidance came from the ECMWF global model and the limited area model LAMI. The former showed a marked warm-moist Sirocco flow coming from the Adriatic Sea onto the coast at all levels, the latter discerned a distinct cold air flow from the north-east along the foothills of the Alps. The integrated observing network of the Centro Meteorologico di Teolo ARPA Veneto revealed this cold-air structure and helped the forecaster in the choice of the forecast and underpin the snowfall alert to the road authorities. It is argued that this feature is a crucial element for the occurrence of snowfall over the Veneto plains, and that the high-resolution numerical weather prediction model was essential in describing this mesoscale feature. The nature of the north-easterly flow is thought to be a combination of a Bora like flow and a barrier jet induced by flow blocking by the Alps.

Domaines: Sciences de la Terre

M. Monai, A. M. Rossa, A. C. Bonan. Partitioning of snowy and rainy precipitation in a case of a north Adriatic frontal passage. Advances in Geosciences, 2006, 7, pp.279-284. ⟨hal-00296926⟩