Storm Forecast
Valid: Sat 22 Jul 2006 06:00 to Sun 23 Jul 2006 06:00 UTC
Issued: Fri 21 Jul 2006 17:06
Forecaster: DAHL

SYNOPSIS

E of Atlantic upper low ... wich will eventually move towards the N British Isles ... rather weak meandering upper W/SWLY flow will be present over north-central Europe ... merging with rather intense NRN frontal zone covering Scandinavia and NW Russia. Relatively weak SFC low is accompanying the Atlantic upper low ... otherwise ... quiescent SFC conditions persist across Europe.

DISCUSSION

France

Current thinking is that numerous storms will form ahead of weak mid/upper level disturbances over France and the S UK ... and spread into W Germany/Benelux late in the day/evening. Isolated TSTMS will likely also form farther E over Germany and the Alpine Region during peak-heating hours. Mid-level flow over France will be on the order of 10 to 15 m/s ... which should be marginally sufficient for a few severe storms given rather decent CAPE ... numerous outflow boundaries from previous convection to interact with ... and anticipated large coverage of the storms. Main threats should be large hail and severe outflow winds.

S Belarus

Another focus appears to exist across Poland and the Belarus in weakly unstable/weakly capped air mass ahead of weak upper vort max. 700 hPa flow across the Belarus is expected to be on the order of 15 m/s ... but minimal CAPE and lack of strong mesoscale LL ascent should limit organized severe threat. However ... a few multicellular storms ... capable of producing marginally severe hail/wind gusts could occur ... but coverage should be too low for a categorical risk.

N Spain

Isolated late-afternoon TSTMS may develop over N Spain ... these storms will likely develop strongly negative buoyancy in their downdrafts given deep/dry CBLs ... wich may briefly result in severe outflow winds. Organized threat should be too low for a level one however.