Storm Forecast
Valid: Sun 27 Apr 2008 06:00 to Mon 28 Apr 2008 06:00 UTC
Issued: Sat 26 Apr 2008 21:14
Forecaster: SCHLENCZEK

SYNOPSIS

Ahead of an upper shortwave trough over the east Atlantic, cyclogenesis is expected southwest of the British Isles. The trough will shift northeastward and the attendant cold front will affect the British Isles, northwestern Iberia and France while the upper ridge over central Europe will translate eastward. Warm and stable conditions will prevail over the central Mediterranean, central and eastern Europe. Upper level cut off low located over the Aegean Sea moves northward during the period.

DISCUSSION

...Northern Spain...western France...

Ahead of the approaching upper trough, low level moisture is forecast to increase which will likely result in some hundred J/kg of CAPE. Although high cloud fields as indicated by high upper level moisture may hinder insolation, convective initiation is expected over northern Spain and southwestern France in the afternoon. Deep layer shear in order of 15 m/s and steep mid level lapse rates allow some organized multicellular storms, capable of producing isolated large hail and gusty winds. Storms will likely continue during the evening as they move northeastward.

...Ireland and western UK...

Cold upper airmass will overspread the region during the day, leading to steep mid level lapse rates and a few hundred J/kg of CAPE. Convection should be mostly non-severe, but good LL buoyancy as well as low LCL heights during the afternoon suggest that a few brief tornadoes / waterspouts are not ruled out.

...Western Turkey...

On Sunday morning, an upper level vort max will affect western Turkey where a few hundred J/kg of CAPE should be present. Deep layer shear as well as low level shear will be rather weak but low LCL heights, steep LL lapse rates and good LL buoyancy are expected and a funnel / brief tornado is not ruled out.

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