Storm Forecast
Valid: Sat 03 Jun 2023 06:00 to Sun 04 Jun 2023 06:00 UTC
Issued: Fri 02 Jun 2023 20:53
Forecaster: PUCIK
A level 2 was issued over Algeria for very large hail, severe wind gusts and excessive rainfall.
A level 1 was issed over much of southern and southeastern Europe mainly for excessive rainfall, marginally large hail and isolated downbursts.
A level 2 was issued over central Turkey mainly for large to very large hail and severe wind gusts.
A level 1 was issued over Caucasus and eastern Turkey mainly for severe wind gusts and large hail.
A level 2 was issued over northern Caucasus and southern Russia mainly for large to very large hail and heavy rainfall.
A level 1 was issued across western and northwestern Russia mainly for severe wind gusts and also tornadoes in the northern third of the area.
SYNOPSIS
An extensive high pressure system over the Atlantic dictates the weather pattern across majority of Europe. Dry airmass has overspread large parts of north and central Europe. Moister airmass with nonzero CAPE is forecast south and east of the cold front that will run from central France across the Alpine range into Serbia, Romania and then curve further northeast towards Ukraine and Russia. Thus, thunderstorm activity will be confined primarily to the southern and eastern Europe. Majority of this activity will be under weak prevailing flow and disorganised.
More organised storms are expected over northern Africa, on the southern flank of a subtle low at mid to upper troposphere, over Russia ahead of an advancing deep trough and over Turkey, and over Caucasus ahead of a short-wave trough.
DISCUSSION
... Algeria ...
Heat low is forecast to form over northern Africa, yielding northeasterly flow from the sea. Surface flow will quickly veer to strong southwesterly flow aloft, yielding long and curved hodographs with locally more than 20 m/s of 0-3 km shear. While NWP models disagree concerning the details, numerous rounds of storms will be possible over the area. The first round, in the morning, will likely be elevated, giving way to more surface-based storms in the afternoon. Expect well organised multi or supercells capable of very large hail and damaging wind gusts.
... Spain through southern France, Alps, Italy into Romania and Greece ...
Scattered to widespread storms will form in diurnally-driven regime. Forecast soundings and hodographs suggest weakly organised multicell clusters with threat of very heavy rainfall, marginally large hail or downbursts. Downburst activity is more likely over drier areas with more abundant surface heating that will yield larger T-Td spreads.
... Turkey ...
Widespread storms are forecast over the country, coverage decreasing towards southeast. Within the Lvl 2, models simulate large amounts of CAPE above -10C isotherm along with 15 - 25 m/s of 0-6 km shear, suggesting potential for very large hail in supercells. Storms may grow upscale during the day with one or two clusters of storms capable of severe wind gusts. Severe wind gust may be the dominant threat over the southeastern part of the Lvl 1, where deep and dry boundary layer will be present. Heavy rainfall will be of main concern over western Turkey, where slower moving storms will combine with moister profiles.
... Northern Caucasus, Southern Russia ...
Two rounds of storms will be possible in this area. First, isolated supercells may form along the Caucasus and move to the forelands given 15+ m/s of deep-layer shear. Abundance of CAPE suggest potential for large or very large hail. Further storms are expected overnight with the approach of the cold front. These storms will form in weaker vertical wind shear, but the high overall coverage will net higher rainfall risk than in the afternoon hours.
... Western to Northwestern Russia ...
Scattered to widespread thunderstorms will form along an advancing cold front in this region. Strong linear forcing, combined with moderate 0-3 km shear suggests potential for squall line capable of isolated severe wind gusts. Further north, along the warm front advancing north, models simulate curved hodographs with 10+ m/s of 0-1 km shear, suggesting threat of tornadoes. The threat is conditional on the presence of SBCAPE along the warm front, which is something that models do not have agreement about.
