Storm Forecast
Valid: Mon 08 Jun 2020 06:00 to Tue 09 Jun 2020 06:00 UTC
Issued: Sun 07 Jun 2020 21:41
Forecaster: GROENEMEIJER

A level 2 was issued across NE Poland, extreme W Belarus, central Lithuania, central Latvia, central and eastern Estonia, parts of Russia's Pskov and Leningrad Oblasts and extreme southeast Finland for large hail and to a lesser extent for wind and local extreme rainfall.

A level 1 was issued across an area surrouding the level 2 including parts of Slovakia, Hungary, Ukraine and the North-Central Balkans mainly for isolated large hail.

A level 1 was issued for Russia's Vladimir, Orjol, Lipetsk and Tula Oblasts mainly for large hail, severe wind and heavye precipitation.

A level 1 was issued for SE Spain mainly for large hail.

A level 1 was issued for the Aurès mountains of NE Algeria and Tunisia mainly for large hail.

A level 1 was issued for parts of North and Central Turkey mainly for large hail and severe wind gusts.

A level 1 was issued for a part of North Italy mainly for large hail.

SYNOPSIS

A frontal zone stretches approximately along a line from Archangelsk-Helsinki-Riga-Warsaw-Budapest-Split and forms the boundary between humid air to the east and drier, cooler air to the west. On the warm side of the frontal zone, convective initiation during the afternoon is expected by the consensus of global NWP models, despite little large-scale forcing for upward motion. In the somehwat cooler air to the west of the front, as well as in the warm air across Russia and Turkey, more isolated areas exist with a lower convective risk strongly modulated by intense insolation. Across SE Spain, the approach of a shortwave trough assists in priming the environment for isolated severe storms.

DISCUSSION

Large area from Balkans to Northwest Russia...

Stronger along-front mid-level winds are located across the Baltic countries and Finland. There, storms have the highest chance to become well-organized due to the resulting deep-layer shear of 15-20 m/s. Some supercells and well-organized multicells will likely develop with a main threat of large hail and a lesser risk of severe winds and high precipitation. Across Estonia, SE Finland and adjacent parts of Russia severe winds are an important risk as well because of the stronger low-level background flow. There, an isolated tornado cannpot be ruled out either. During the evening, the storm activity will gradually diminish.

Across Southeast Poland and further south, wind shear will be weaker and storms should generally be less organized. That said, a number of strong multicells could still locally produce some large hail and locally very heavy rain.

Russia's Vladimir, Orjol, Lipetsk and Tula Oblast...

The level 1 has been issued because very high MLCAPE of 2000-3500 J/kg predicted by NWP models suggest that isolated pulse storms may develop locally, capable of producing some large hail, severe winds and very heavy rain.

A level 1 was issued for SE Spain mainly for large hail...

Aided by an approaching shortwave trough, moderate instability is expected to develop across the mountains of SE Spain. In combination with 0-6 km bulk shear of about 20 m/s, a few supercells with a risk of large hail may develop.


Northeast Algeria, North Tunisia...

Isolated supercell storms may develop over the Aurès mountains with a risk of large hail courtesy of the strong ~25 m/s 0-6 km bulk shear.

Parts of North and Central Turkey...

Ample instability is expected to develop across the higher terrain of Northern Anatolia. Despite modest mid-level winds and hence limited vertical wind shear, a couple of stronger multicells might develop with a risk of large hail. The deep and relatively dry boundary layer will aid the development of strong downdrafts with a resulting localized risk of downbursts.

Northern Italy...

Moderate instability and moderate 10-15 m/s deep-layer shear and essentially no CIN set the stage for widespread storm development, with an attendant risk of large hail and heavy rain with the strongest cells.