CONVECTIVE FORECAST
VALID 06Z SUN 05/12 - 06Z MON 06/12 2004
ISSUED: 04/12 18:58Z
FORECASTER: DAHL

There is a slight risk of severe thunderstorms forecast across the central Mediterranean regions.

General thunderstorms are forecast across the western and central Mediterranean regions.

SYNOPSIS

Moderately strong SWLY upper flow will persist over the central Mediterranean ahead of the quasistationary upper cut-off low ... with meandering WLY upper jet stretching across NRN portions of Europe. Fairly intense imbedded short-wave trough is expected to cross N-central Europe late in the day. At the SFC ... series of intense SFC lows is present over the N Atlantic and N Europe on Sunday per latest model guidance ... with weak but rather extensive SFC low persisting over the central and W Mediterranean.

DISCUSSION

...SLGT area...
It looks that best thermodynamic setup ... mainly featuring steep low-level lapse rates and a rather moist boundary layer ... will be present within 850 hPa theta-e tongue over the S-central Mediterranean ... the Tyrrhenian and Ionian Sea. CAPE should remain fairly weak ... though CAPE density is fairly low between the LFC and about 5 km height as revealed by Saturday's 12Z launches.

850 hPa flow of 10 to 15 m/s should provide sufficient shear for rotating updrafts ... though persistence of the cells may be somewhat limited given only about 15 m/s deep shear. However ... a brief mesocyclone ... capable of producing some hail ... severe straight-line winds and a tornado or two may occur in this environment.

Coverage of TSTMS is somewhat uncertain ATTM ... but given the relatively strong low-level shear and indications that at least one vort max will cross the central Med during the day ... a SLGT is once more marginally warranted.

...S Norway...
During the first few hours of the period ... a few shallow TSTMS may occur in strong upslope flow W of the S-Norwegian Mountains ahead of vigorous short-wave trough. Coverage is expected to be too limited for a TSTM outlook ... though convection may slightly augment the strong gradient back-ground flow.

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