CONVECTIVE FORECAST
VALID Wed 07 Dec 06:00 - Thu 08 Dec 06:00 2005 (UTC)
ISSUED: 06 Dec 22:42 (UTC)
FORECASTER: GATZEN

SYNOPSIS

Upper long-wave trough present over Europe. At its periphery ... well-developed trough axis/vort-max accelerates over central Mediterranean ... reaching Adriatic Sea at the end of the period. Upstream ... another vort-max/short-wave trough ejects into European trough and propagates southeastward over British Isles and France. At lower levels ... cold airmass is present over most of the forecast region and spreads southeastward into southern Balkans/ western Turkey.

DISCUSSION

...Northern Mediterranean ...
Intense upper vort-max travels over the region. Affected cold airmass is characterized by steep low-level lapse rates over relatively warm sea surface. Low-level moisture indicated by latest ascends over northern Mediterranean should advect southeastwards while quite dry low-level airmass spreads into northwestern Mediterranean behind a cold front. Although amount of instability is uncertain ATTM ... some CAPE seems to be likely over northern Mediterranean ... especially over Italy region. As the upper vort-may approaches ... QG forcing is expected. At lower levels ... convergence should be present ... and showers and a few thunderstorms are forecast to develop. Vertical wind shear will be moderate ... and a few organized convective cells are expected ... capable of producing severe wind gusts ... isolated large hail and probably a tornado or two. Allover threat should be rather low over a broad region.

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