Storm Forecast
Valid: Mon 31 May 2010 06:00 to Tue 01 Jun 2010 06:00 UTC
Issued: Sun 30 May 2010 20:31
Forecaster: GROENEMEIJER

A level 1 was issued for parts of the Ukraine mainly large hail.

A level 1 was issued for E Romania and NE Bulgaria for large hail.

A level 1 was issued for the NW Balkans and W Hungary primarily for excessive precipitation.

SYNOPSIS

An intense cold upper-level low over SE Germany and western Czechia moves SEward reaching Serbia on Tuesday morning while weakening. On its SW flank, a very strong jet is present near the tropopause. Surface cyclogenesis is expected over the NW Balkans before the cyclone moves onto the Pannonian Plain and deepens further.

DISCUSSION

NW Balkans, W Hungary...

A convective/stratiform hybrid high precipitation is likely, with local accumulation up to ~100 mm possible in places within the level 1 area as intense lift in the left exit region of the upper-level jet streak overspreads the relatively moist air-mass across the area. The most intense precipitation is forecast on Monday morning. Since the convective component to the event is limited we will refrain from issuing more than a level 1. Small hail and mostly sub-severe wind gusts will be possible in addition to the excessive rainfall.

Central to Western Ukraine...

Relatively moist air is slowly advected into the area from the south. Together with diurnal heating, a substantial amount of CAPE, 1000-2000 J/kg should be able to develop. In spite of the weak wind shear, any multicell storms that develop during the afternoon could produce marginally severe (2-3 cm) hail.

E Romania, NE Bulgaria...

As with the other level 1 region, sufficient moisture should be available in this area that together with abundant insolation and moderately steep lapse rates could yield a few marginally severe hail events.