Storm Forecast
Valid: Tue 02 Jun 2020 06:00 to Wed 03 Jun 2020 06:00 UTC
Issued: Mon 01 Jun 2020 22:51
Forecaster: DAFIS
A level 2 was issued for SW Russia for large and very large hail, severe wind gusts, excessive precipitation, and tornadoes.
A level 1 was issued for parts of Russia, Georgia, Azerbaijan, Armenia, and Turkey for large hail, severe wind gusts and excessive precipitation.
A level 1 was issued for Bulgaria, NE Greece and Turkey mainly for large amounts of small hail.
A level 1 was issued for parts of Ukraine and Belarus mainly for large amounts of small hail.
A level 1 was issued for North Italy, Slovenia and W Croatia for large hail and severe wind gusts.
A level 1 was issued for Spain for large hail and severe wind gusts.
SYNOPSIS
Low geopotentials will continue to affect Eastern Europe as a cut-off low has developed over Ukraine and is surrounded by several short-wave troughs. The strong southerly flow at the eastern parts of this low-pressure system will create favorable conditions for DMC in Russia, where all kinds of severe weather are expected. More to the west, a weak ridge developed in Iberia but northern parts of Spain will be affected by a fast-moving satellite-trough, associated with another cut-off low in the Azores. Another short-wave trough currently (Mon 01/06 21z) affects South France and is moving fast towards Italy, destabilizing the area. Finally, weak instability is expected in Sweden and a few non-severe and diurnally driven storms will develop.
DISCUSSION
.... Russia ....
The persistent southerly flow associated with the trough to the west, over the Balkans, brings very moist air masses from the Black Sea in SW Russia. The weak cap in the morning of Tue 02/06 will not prevent storms to develop before the maximum diurnal heating because an approaching short-wave trough before 12z will most probably provide the necessary lift for the first storms to develop. The first cells will quickly become supercells into this strongly sheared environment characterized by 1500-2000 J/kg MLCAPE and veering winds. The veering vertical profiles will create more than 200 m2/s2 SREH0-3km, indicating the potential for strong rotation of the storms. The isolated storms will be able to produce all kinds of severe weather but mainly very large hail and severe wind gusts. The low-level helicity, high SBCAPE and low LCLs increase the threat for tornadogenesis, even though winds are weak in the lowest 3km, supercells can modify their environment and enhance locally the wind field. In the late afternoon and night, storms travelling north will become more elevated and severe weather threat will gradually be reduced.
.... Russia (level-1), Georgia, Azerbaijan, Armenia, and Turkey ....
The CAPE-Shear overlap over this area will increase the chances for severe storms to develop and produce large hail and severe wind gusts. South from Caucasus storms will mostly organize in MCSs travelling N-NE, but north of the mountain range storms will be able to become supercells given higher CAPE-Shear overlap and more helicity.
.... Ukraine, Belarus, Bulgaria, NE Greece and Turkey ....
Under the core of the cut-off low, slow storm motion and saturated vertical profiles increase the threat for large amounts of hail accumulation at the surface, during slow-moving storms in Belarus and Ukraine.
Similar conditions are found more to the south in Bulgaria, Greece and Turkey where storms will propagate faster under the influence of a shrot-wave trough, but low geopotentials with freezing levels below 3 km height increase the threat for hail at the surface.
.... North Italy, Slovenia and W Croatia ....
A mid/upper-level wave will cross N Italy in the early afternoon of Tue 02/06, providing an extra lift to unstable air masses, along with the help of diurnal solar heating. Steep lapse rates, CAPE exceeding 1000 J/kg and DLS locally exceeding 10 m/s will create an environment conducive for large hail. Severe wind gusts will also be a threat due to high delta-thetae values with LCLs above 2000 m height.
.... North Spain ....
Similar conditions with Italy are expected in N Spain, but weaker shear. Diurnally driven storms will get benefit from more than 1000 J/kg CAPE, where steep mid-level lapse rates create locally fat CAPE profiles (high NCAPE).
