Storm Forecast
Valid: Sat 24 Nov 2007 11:00 to Sun 25 Nov 2007 06:00 UTC
Issued: Sat 24 Nov 2007 10:32
Forecaster: TUSCHY

SYNOPSIS

A strengthening high pressure area over the northeastern Atlantic Ocean and a southward moving 160kt upper-level speed max on the downstream side of this feature result in a re-strengthening upper-level trough east of Scotland.
Again, a broad but gradually weakening upper-level trough is still placed over SW Europe while attendant WAA results in warm and stable conditions over SE Europe.

DISCUSSION

...Western and central Mediterranean ...

There are two areas of enhanced thunderstorm activity. One will be over northern Italy and the Adriatic Sea, where mid-levels cool-down, supporting deep convection.
A shallow cyclonic swirl just west of Corsica moves slowly towards the east / northeast, but presentation on latest IR / WV images support the model consensus in weakening this feature, while shifting towards NW Italy.

Another area for scattered thunderstorms will be south of Spain, as a broad LL depression over NW Africa and cold mid-levels result in low-end to moderate instability release and numerous foci for enhanced forcing.

In both areas, wind shear is weak and hence no threat of organized thunderstorms can be expected.
Stronger storms over N-Italy could produce gusty winds and south of Spain an isolated waterspout due to better LL CAPE can't be ruled out but overall probabilities are too low for issuing any level area.

...West-central Norway...

Latest IR images indicate an area of enhanced convection north of Scotland. This activity should affect Norway during the early evening and night hours.Despite the cold cloud tops and the healthy looking postfrontal convective activity, confidence is low that more than a few SFLOC reports can be expected. Anyway, EL temperatures cool down significantly, indicating deep convection and a combination of a humid BL and steep mid-level lapse rates could support a few thunderstorms along the coast. We therefore issued a small thunderstorm area.
Mainly marginal hail but also gusty winds could accompany stronger storms.