Storm Forecast
Valid: Fri 02 Jun 2006 06:00 to Sat 03 Jun 2006 06:00 UTC
Issued: Thu 01 Jun 2006 20:23
Forecaster: TUSCHY

SYNOPSIS

A well developed omega-like weather pattern will be present over most parts of Europe ( with one trough over the eastern Atlantic Ocean and the other one over central Europe )...This kind of constellation is favorable for cold air intrusion far towards the south and therefore for a broad area of TSTM development.
Southwest,north-central and northeast Europe will see high pressure and stable conditions.
Portions of northern Europe will be affected by a double barrel low pressure system and a cold front will cross parts of Norway and Sweden during the afternoon hours from the WNW-SE.

DISCUSSION

....Southeastern Europe....

Despite some minor uncertainties, the stage is set for a defined severe weather event over Romania!

An intense trough over central Europe will continue to dig further southwards, resulting in a broad S-SW-erly flow over SE Europe.
A well developed upper-level jet streak will round the base of this trough and should reach Bulgaria during the morning hours... This wind max. and another one ( departing towards the NE ) will place the region under a broad and intense upper-level divergence area ( coupled jet configuration ).
Broad area of pressure fall over SE Europe will help to sharpen a NW-ward retreating warm front, which should move as fast west as western Romania.
Intense upper-level divergence, retreating warm front and approaching trough axis from the SW should yield a favorable environment for early TSTM development ( Albania-Serbia and Montenegro-western Romania ).
GFS forecast 200-500 J/kg SBCAPE and this looks reasonable, given pretty steep mid-level lapse rates and a fairly correct dewpoint assumption of the model.... DLS in the order of 25-30m/s would favor a severe wind gust risk, especially, when a line of storms with embedded bowing segments can develop.

As a result of a broad area of low pressure over SE Europe and the arriving upper-level jet , models try to develop a seperate a weak low-pressure area somewhere over N-Bulgaria/SW Romania... Theta-E analysis indicate a developing waving frontal structure over Romania (tranformation back towards a cold front ) during the afternoon hours and models generate quite significant convective precipitation signals... Despite the fact that early convection initiation could hinder insolation and that global models like GFS have problems with such small-scale and weakly developed features, conditions look fine for a few organized TSTMs to evolve....
Kinematic parameters would allow all kind of severe weather ( including isolated tornadoes, severe wind gusts and large hail )!

Area along the western coastal areas of the Black Sea were also included into a level-1 area... Despite the fact that pretty warm mid-levels and a strong cap should suppress convection development, intense diabatic heating could locally overcome cap ....Each developing storm should become supercellular pretty fast with an attendant threat for large hail and severe wind gusts!

Intrusion of a drier mid-level airmass should suppress TSTM development over Bulgaria and westwards during the late afternoon hours.

....Central Mediterranean....

Cold air intrusion in the mid-levels under the base of an upper-level trough over the central Mediterranean should help to steepen lapse rates and cause a pretty widespread low-end-moderate instability release.
Conditions are quite favorable for scattered storms to develop with a few waterspouts....there will also be a marginal hail threat with each stronger TSTM.

....Extreme SE-Norway and S-Sweden...

SE-ward racing cold front should cross the area of interest during the afternoon hours... Despite the fact that models develop no instability, strong forcing along the front and steepening lape rates could be enough for isolated storms to develop....Marginal hail with stronger cells would be the main risk.