CONVECTIVE FORECAST
VALID 15Z WED 30/06 - 06Z THU 01/07 2004
ISSUED: 30/06 14:51Z
FORECASTER: DAHL

General thunderstorms are forecast across E Europe ... parts of N Europe and west-central Russia.

General thunderstorms are forecast across E Spain ... Italy ... N UK.

SYNOPSIS

Main feature this remaining period is a strong vort max which is rotating about the periphery of mean E-Atlantic upper low and which is expected to reach NE Germany/NW Poland earlyThursday morning. Another upper low will persist over SE Europe ... also exhibiting several perturbations at its periphery. At low levels ... Low pressure is dominating the NRN and N-central European regions ... with quiescent conditions prevailing over the SRN portions of Europe.

DISCUSSION

...UK...
In the wake of the cold front now stretching across SE England ... chance of a few TSTMS exists with shallow convection forming in the wake of the front. Strongest shear will likely be S of the deepest mixing ... and severe TSTM threat appears to be rather low. Over the SRN UK ... convection should remain too shallow to pose an appreciable severe weather threat.

...E Spain...
Another round of diurnally driven high-based TSTMS has just commenced over E Spain ... quite large dewpoint depressions in the deeply mixed boundary layer will likely support a few downbursts. TSTMS should fail to organize owing to lack of shear ... but storms may merge into larger clusters during the evening hours before they dissipate.

...west-central Russia...
Soundings from W-central Russia reveal nearly uncapped and saturated profiles ... with little allover CAPE but appreciable CAPE in the lowest km. Though large-scale deep shear and SRH is quite meager ... any vorticity /either vertical or horizontal/ that can be created will undergo strong stretching/tilting at low levels once ingested into an updraft. This may be supportive to an isolated tornado or two ... conditional on the presence of meso- and convective-scale boundary-layer features providing the vorticity.

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