Storm Forecast
Valid: Fri 04 Jun 2010 06:00 to Sat 05 Jun 2010 06:00 UTC
Issued: Thu 03 Jun 2010 18:35
Forecaster: TUSCHY
A level 1 was issued for parts of E-Poland, Belarus and W-Russia mainly for severe wind gusts and large hail and to a lesser extent for tornadoes.
SYNOPSIS
High pressure builds in from the Atlantic with calm conditions over W-Europe. A strong low over NE-Europe and an upper low over Greece will be the foci for enhanced convection.
DISCUSSION
... Belarus and W-Russia ...
A SW-NE elongated cold front gradually shifts eastwards during the forecast and will be the focus for intense, deep convection. However, that part of the cold front, which sprawls into our forecast area, remains displaced from best forcing and shear, so a level 1 will cover the severe risk. Despite rapid clustering along the eastward sliding front, organized multicells/isolated supercells are forecast with all kind of severe, mainly large hail, strong to severe wind gusts and excessive rainfall - the latter one fostered by the influx of a warm/moist and therefore unstable air mass and slow storm motion. GFS ramps up LL shear along the front and even keeping convective feedback problems in mind, some directional shear will be present along the front. An isolated tornado event is possible. This cold front remains active (convective-wise) until well after midnight although overall severe risk gradually diminishes with relaxing shear.
Models still diverge when and where a surface depression consolidates over W-Russia, which dictates where the highest supercell risk exists. We expect a rapid increase just along the edge of our forecast area and hence no level 2 was introduced and we think a broadly brushed level 1 will be the best choice for now.
... General thunderstorm areas along the Mediterranean ...
Locally good CAPE but weak shear limits the risk for organized convection although an isolated large hail event is well possible beneath stronger updrafts. Also, along the coast of S-Italy, an isolated water spout/tornado event is feasible, if enough LL CAPE builds up. Right now, models remain modest in respect of LL CAPE, so no level 1 was introduced.
