Storm Forecast
Valid: Wed 06 Apr 2016 06:00 to Thu 07 Apr 2016 06:00 UTC
Issued: Wed 06 Apr 2016 06:19
Forecaster: TASZAREK

A level 1 was issued for SE Poland, W Belarus, W Ukraine, and parts of Slovakia and Hungary mainly for the large hail.

SYNOPSIS

A warm and moist unstable sector in weakly sheared environment, weakening cap and a lowering pressure continues to cover E and SE parts of Europe, thus creating good conditions for the development of DMC. SW Europe is under influence of Azores ridge and convection is unlikely over Iberian Peninsula and SE France. Mediterranean Sea is currently too cold and contain not enough boundary layer's moisture to provide any thermodynamic instability. In NW Europe a shortwave trough is expected to pass British Isles, Benelux and NW Germany with a possible lightning threat in low topped cells. However, due to marginal CAPE and lack of good overlap with shear, severe weather threat is marginal.

DISCUSSION

...SE Poland, W Belarus, W Ukraine, and parts of Slovakia and Hungary...

A nice overlap of boundary layer's moisture exceeding 10 g/kg (mean mixing ratio) and a steep lapse rates of even more than 7.5 K/km together with intense diurnal heating create good conditions for the development of DMC. A CAPE in such setup is expected to reach a maximum magnitude up to 1500 J/kg, locally (E Slovakia, SE Poland) overlapping with 15 m/s DLS. Although in most of the area a vertical wind shear is likely to be very weak (~ 10 m/s), a steep lapse rates and rich moisture in low levels may result in a large hail up to 2-3 cm, and even larger over parts of Slovakia and Poland where an overlap with wind shear will be the most favorable. Thunderstorms should initiate in the afternoon hours and reach the peak intensity around 15-16 UTC. After the sunset, convection should fade over most of the lightning areas. Due to high EL's with tops below -50 C, moderate CAPE (~ 1000 J/kg) and a lot of moisture entering the updraft, locally the lightning intensity may be high.