CONVECTIVE FORECAST
VALID 06Z SUN 01/08 - 06Z MON 02/08 2004
ISSUED: 31/07 17:47Z
FORECASTER: DAHL

There is a slight risk of severe thunderstorms forecast across the W Ukraine and Moldavia.

General thunderstorms are forecast across SW ... S ... E and N Europe.

SYNOPSIS

Seasonaby weak upper flow has established over Europe ... with a weak ridge over western/central Europe. Weak elongated upper low persisting over the Baltic States. Upper low over the Balkans is progged to weaken and eventually merge with the Baltic upper low. Several weak short-wave troughs are imbedded in this flow regime. At low levels ... weak high pressure area covering Scandinavia and the North Sea is progged to retreat north a bit with weak cyclonic flow persisting over SE Europe.

DISCUSSION

...Ukraine ... Moldavia...
Saturday's 12 ascents from E Europe revealed MLCAPEs partly in excess of 2000 J/kg ... these will likely persist through Sunday. Widespread TSTMS should initiate during peak heating hours in weakly capped envionment ... storms will likely merge into one or more larger clusters late in the day. Deep shear is progged to exceed 20 m/s over the S Ukraine ... with 0-1 km shear expected to range from 7 to 10 m/s over the Ukraine and the Belarus late in the day. Expect several quite vigorous supercells to develop over this region ... capable of producing the entire range of severe weather ... primarily large hail ... damaging wind gusts ... and a tornado or two given weak CINH and strong accelerations above the LFC. As storms will likely merge into one or more larger clusters ... main severe-weather threat may shift towards large amounts of precip.

...SE Germany ... Austria ... N Balkans...
Ahead of weak trough pivoting about the merging Balkan/Baltic upper lows ... scattered TSTMS will likely initiate with diurnal heating. Instability should be quite meager ... with marginal deep-layer shear. However ... a mesocyclone or two will likely form ... posing a threat for large hail and strong/severe wind gusts.

...Portugal ... W Spain...
DCVA-regime is expected to overspread Portugal and W Spain late in the day ... which will likely promote scattered TSTMS. Given their high-based nature ... and 15 to 20 m/s mid-level flow ... potential for short bowing lines exists ... primarily posing a threat for damaging wind gusts. TSTM coverage is expected to be too low for a SLGT.

...S Finland...
Low LCL heights and 7.5+ m/s low-level shear may promote brief/small mesocyclones ... capable of producing some hail and a brief tornado or two. Threat is too low for a SLGT.

...Turkey...
Models agree in generating some CAPE ... large-scale UVV's and precip. Given about 20 m/s deep shear ... strong outflow winds and possibly some hail ... both approaching severe levels ... may occur.

Otherwise ... especially Italy ... France ... Spain ... weak CAPE will likely develop during the day ... and given weak capping ... a few isolated TSTMS may develop during the day. Organized severe will be unlikely though.

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