Storm Forecast
Valid: Tue 05 Jan 2010 06:00 to Wed 06 Jan 2010 06:00 UTC
Issued: Tue 05 Jan 2010 03:08
Forecaster: VAN DER VELDE
A level 1 was issued for parts of Sardinia, Corsica, western Italy mainly for a chance of excessive convective rainfall.
A level 1 was issued for parts of and Croatia, Montenegro and Albania for a chance of excessive convective rainfall, severe gusts and tornadoes.
SYNOPSIS
A very large trough covers most of Europe, with its axis from Scandinavia to Spain. Several smaller lows are circulating around its perimeter: around the British Isles, western Mediterranean Sea, and Finland.
DISCUSSION
...Sardinia, Corsica, western Italy...
Flash floods may occur as result of persisting onshore advection of convective cells and lifting of moist air. However, the cell motion itself is rather fast so individual cells may not contribute a lot. Additionally, weak instability stretches till Corsica and the Italian coast near Elba, where a stationary frontal zone with good lifting can produce significant amounts of stratiform rainfall, and high SREH values are found in the vicinity. A storm forming in this region could become supercellular and may produce a tornado or waterspout, which however are not ruled out elsewhere.
...southern Croatia, Montenegro and Albania...
During the night instability and forcing increase and convective flash floods may occur (similar story as the region described above). The environment of high shear (>17 m/s LLS, >20 m/s DLS and SREH >300 mē/sē) can grow mesocyclones in storms which may become tornadic. Severe gusts (>25 m/s) are also possible.
