Storm Forecast
Valid: Sun 23 Mar 2008 06:00 to Mon 24 Mar 2008 06:00 UTC
Issued: Sat 22 Mar 2008 22:09
Forecaster: DAHL

SYNOPSIS

Unusually deep and intense upper trough persists over Europe ... leading to a deep, broad, and intense SSWly flow from the central Mediterranean all the way up to NW Russia. Ahead of a peripheral vort max, a SFC low is developing over the W Mediterranean traveling into the N Balkans by early Monday morning. The cold front of this low will cross the northern and central Mediterranean on Sunday and will likely be focus for isolated severe convective weather.

DISCUSSION

... central and northern Mediterranean ...

Thunderstorms are expected to persist across the central and northern Mediterranean ahead of and along the cold front trailing from the N Mediterranean SFC low. Additional, mainly elevated storms are anticipated in the strong WAA regime NE of the SFC-low center. Those storms that are surface based will benefit from very ample shear, partly exceeding 35 m/s in the lowest 6 km and 15 m/s in the lowest 1 km. There will be two negatives ... one being a simulated lack of CAPE and the other being a somewhat ill-defined large-scale vertical motion field. Still, at least scattered thunderstorms should persist along and ahead of the cold front. These will likely organize into linear segments and mesocyclones, capable of severe wind gusts, marginally severe hail, and maybe also a few tornadoes, given weak LL capping and strong LL shear. However, latest radiosonde observations suggest that LCLs may remain somewhat high, but this may be offset by the otherwise favorable fields.

... western Mediterranean ...

Convection developing over the western Mediterranean in the polar air in the wake of the cold front will also have some severe potential given that part of it develops amidst strongly sheared kinematic environment. Expect marginally severe hail, severe wind gusts as well as a tornado or two with this activity.