Abstract : 2G.14
Case study on Genoa Cyclone with Mistral 13-15 February 2005
Natasa Strelec-Mahovic, Dunja Drvar
Meteorological and Hydrological Service
This case study tackles the occurance of very strong Mistral spreading from France and Switzerland over the Western Mediterranean. Strong wind with gusts up to 85 knots persisted throughout the whole day on 14 February and is well documented in synop measurements.
Mistral was caused by cyclogenesis in Genoa Bay triggered by the strong northerly upper level flow. At the beginning of the cyclogenesis the cold air flow was tunnelled through the Garone Valley between the Pyrennes and the Massif Central and through the Rhone Valley between the Massif Central and the Alps.
Development of the cyclone is followed in the satellite images. Air masses that took part in the development are analized by means of colour composite of several Meteosat 8 channel data (Airmass RGB).
The jet streak played an important role in the process of cyclogenesis as can be seen in the upper level wind field.
The layer of Mistral is analyzed with the use of vertical cross section (VCS) which showes the origin, persistence and strenght of the wind. The VCS of the wind field parallel to the coast of France showed the low level jet and the tunnelled effect of the Mistral. In the VCS perpendicularly to the south coast of France the flow over land and over the sea can be followed. During the whole period the maximum of the north-westerly wind was just over the sea (near the coast).