Storm Forecast
Valid: Fri 15 Jul 2011 06:00 to Sat 16 Jul 2011 06:00 UTC
Issued: Thu 14 Jul 2011 20:39
Forecaster: TUSCHY

A level 2 was issued for parts of Serbia mainly for significant hail and severe to damaging downbursts/wind gusts

A level 1 was issued for Hungary all the way to Belarus mainly for large to isolated very large hail and strong to severe wind gusts.

A level 1 was issued for Belarus for the evening and night hours. Next to large hail and strong to severe wind gusts, an isolated tornado risk and excessive rainfall are forecast.

A level 1 was issued for N-Italy and Slovenia mainly for large hail and strong wind gusts.

A level 1 was issued for parts of N-Algeria mainly for large hail and strong to isolated severe wind gusts.

SYNOPSIS

A broad, deep trough covers most parts of central Europe. Along its fringes, numerous disturbances cause unsettled weather conditions. A cold front along its eastern fringe serves as focus for well organized, deep convection. The weather for the far eastern Mediterranean remains stable and hot.

DISCUSSION

... Belarus to Serbia to Italy ...

Gradually eastward moving cold front remains progressive from Belarus to Hungary, but slows down further south. Ahead of this baroclinic zone, a moist and unstable air mass is present with high BL mixing ratios and steep mid-level lapse rates. In general, MLCAPE in the order of 500 - 1000 J/kg is expected with up to 2000 J/kg over parts of Serbia. 0-6 km bulk shear of 20 m/s and augmented storm relative helicity along that boundary favor well organized multicells/isolated supercells with large to isolated very large hail. A more widespread significant hail risk may evolve over Serbia with expected thermodynamic profiles. Next to that, severe downbursts occur with a few damaging events possible again over Serbia. This area was upgraded to a level 2 due to the augmented risk of significant severe events.
During the evening hours, in addition to large hail and strong to severe wind gusts, an isolated tornado risk and a more widespread heavy rain risk may evolve over Belarus in conjunction with a gradually evolving surface wave. Uncertainties in exact deepening rate and placement preclude an upgrade for now. Thunderstorms keep going all night long along that boundary.

Over N-Italy, modest CAPE/shear assist in a few better organized thunderstorms, posing an isolated large hail risk. Thunderstorms gradually decay during the first part of the night.

... E-Spain and N-Algeria ...

In the afternoon, strong heating and weak convergent signals in the surface wind field may support a few thunderstorms. Marginal to isolated large hail and strong wind gusts remain the main hazard.

During the night, thunderstorm coverage increases over far N-Algeria and just offshore, as a large-scale upper trough approaches from the west. Scattered thunderstorms with large hail are forecast.