Storm Forecast
Valid: Tue 19 May 2015 06:00 to Wed 20 May 2015 06:00 UTC
Issued: Tue 19 May 2015 04:39
Forecaster: KAHRAMAN

A Level 2 was issued for SE Spain mainly for large to very large hail.

A Level 1 was issued for W Lithuania for an isolated tornado possibility.

A Level 1 was issued for NW Balkans mainly for large hail.

A level 1 was issued for parts of NW Turkey, NE Greece and SW Bulgaria for large hail.

SYNOPSIS

A major through over W Europe with a deep low pressure over North Sea and a shallow one over S Spain, and a low pressure system over central Mediterranean are the major players of the weather over Europe on Tuesday. Another low pressure system over W Russia leaves the forecast area at the beginning of the forecast period. Patches of shallow lows over central Europe will evolve during daytime with the western through approaching the area.

DISCUSSION

...Britain and NW continental Europe...

Cool air mass above 6-7 g/kg mixed layer mixing ratios around the British Islands and NW coasts of continental Europe results in weak CAPE values over the area. Relatively stacked low over the North Sea ensures lower deep layer shear values, however, northwesterly polar jet over Ireland and southwesterly jet from France to Baltic Sea creates as high as 30 m/s 0-6 km shear, which barely overlaps <200 J/kg MLCAPE area. Marginally severe storms may occur at this narrow band, however, no level is warranted for this area, with remaining uncertainities.

...Spain and NW African coasts...

SE Spain and N coasts of Morocco and Algeria will have weak to moderate latent instability with a warm moist advection from W Mediterranean Sea and Atlantic Ocean at the low levels, under the southern edge of the major cold tongue. Forcing is strong over the area. Up to 25-30 m/s 0-6 km shear area east of Spain will favour supercells / well organized storms over central and SE Spain. Although the CAPE values are not as high, large to very large hail is the major threat here.

...W Lithuania...

An isolated tornado is possible around W Lithuania with moderate CAPE and strong deep/low level shear, and marginal LCL.

...Balkans and central Europe...

Clusters of storms will form over Balkans and Central Europe during daytime, with moderate instability and low shear, and higher LCLs. Main risk is large hail over this area.

...NW Turkey...

Up to 1000-1500 J/kg MLCAPE and ~15 m/s 0-6 km shear is forecast over parts of NW Turkey, with continuous moist advection from Black Sea and Marmara. Instability is capped over N Marmara Region, however, storms will form over Southern parts of Marmara and Western Black Sea mountains, capable of large hail. Microbursts are also not ruled out due to steep lapse rates in the low level.