Storm Forecast
Valid: Fri 10 Nov 2006 06:00 to Sat 11 Nov 2006 06:00 UTC
Issued: Fri 10 Nov 2006 00:00
Forecaster: DAHL

SYNOPSIS

Large-scale upper trough over E-central Europe on Thursday evening ... will continue to dig SEWD ... reaching the Ionian/Aegean region late in the period. Meanwhile ... next upstream Atlantic trough will reach the British Isles and the NW portions of central Europe. High SFC pressure will spread eastward into central and eastern Europe in between these two systems in association with intermediate upper ridge.

DISCUSSION

... S Adriatic Sea ... Ionian Sea ...

Weak CAPE is likely to develop ahead of the cold front which will spread across the Balkans and the NW Mediterranean on Friday. Given generally weak lapse rates ... degree of CAPE is expected to be rather slim ... but sufficient for deep convection. Strong DCVA-related lift will overspread the regions along and ahead of the SFC cold front ... and help initiating TSTMS. Model guidance suggests that TSTMS will spread from the N Adriatic Sea southward into the Ionian Sea/Greece ... and eventually into the Aegean Sea with peak activity expected in the 18Z to 06Z time frame. Deep shear on the order of 20 m/s should be supportive of severe evolution ... and coupled with strong mesoscale ascent ... development of one or more MCSs appears possible. Though main threat will be related to large amounts of rain ... some hail ... severe wind gusts and possibly a brief tornado or two may occur as well ... warranting a LVL1.

... Poland ... Belarus ... Ukraine ...

Deeply mixed polar air will remain in place over Poland ... the Belarus and the Ukraine ... but given unfavorable trajectories from Scandinavia and the Baltic Sea ... convection should be somewhat weaker than on Thursday ... and accordingly weaker electrified. A TSTM area thus does not seem to be warranted.

... northern North Sea ... Norwegian Sea ...

Deeply mixed polar air will reach the N North Sea and the Norwegian Sea late in the period in the wake of a vigorous Atlantic cyclone. Mesoscale fields of enhanced Cu/Cb's ... possibly weakly electrified ... will likely be present in this air mass. This convection may augment the already strong synoptic-scale gradient flow ... but it does not seem that the showers/TSTMS will be the main contributors to the wind threat ... and a categorical risk is thus not issued this time.