Storm Forecast
Valid: Sun 12 Nov 2006 06:00 to Mon 13 Nov 2006 06:00 UTC
Issued: Sat 11 Nov 2006 19:26
Forecaster: DAHL

SYNOPSIS

Upper trough over the North Sea on Saturday evening ... is expected to continue its eastward track across central Europe ... reaching the S Balkans towards Monday 06Z. Associated extensive SFC low will spread across much of central Europe. SFC cyclogenesis is progged to occur over the NW Mediterranean ... spreading into the S Adriatic Sea during the period. Next Atlantic system will reach the British Isles Sunday evening.

DISCUSSION

... E Germany ... W Poland ... N Czech Republic ...

Convection is expected to persist in the deep polar air over the North and Baltic Seas as well as over portions of central Europe. Shear profiles and large-scale forcing for ascent seem to be sufficient to support organization into lines or clusters of the showers and TSTMS especially over NE Germany ... W Poland and the N Czech Republic where shear profiles should be strongest. Expect a few severe wind gusts with this activity ... though a brief tornado cannot be discounted either given strong LLS.

... central Mediterranean ...

It seems that weak instability could develop ahead of the main cold front reaching the NW Mediterranean early in the period. GFS does not advertise negative LIs while NMM does ... but GFS appears to have had problems with warm-sector convection lately ... and am thus inclined to go with the NMM solution. Should deep convection indeed develop ... shear profiles will be supportive of severe evolution given about 15 m/s 850 hPa flow and 20 m/s 500 hPa flow. Given uncertainty about the evolution of the thermodynamic fields ... no categorical risk will be introduced ATTM ... but an upgrade may be necessary on Sunday.