Storm Forecast
Valid: Wed 28 Jun 2023 06:00 to Thu 29 Jun 2023 06:00 UTC
Issued: Tue 27 Jun 2023 21:32
Forecaster: GROENEMEIJER

A level 1 was issued across eastern Spain primarily for large hail.

A level 1 was issued across parts of Greece and Bulgaria primarily for large hail.

A level 1 was issued across parts of Finland, Sweden and Estonia for heavy rainfall and isolated hail around 2-3 cm and severe wind gusts.

SYNOPSIS

A closed low over Belarus is movign eastward into western Russia. North of this system, a stagnant moist unstable air-mass supports scattered to widespread storms, some of which may be marginally severe. South of the low, a shortwave trough will swing from southern Poland to the western Black Sea coast, setting the scene for a few severe storms across Bulgaria and Northeast Greece. Across Spain, a feww storms will likely form on the convergence at the sea breeze front as it movers inland and upslope. The resulting instability should be more than sufficient for some isolated large hail.

DISCUSSION

Sweden, Finland, Estonia...

Relatively high amounts of moisture are in place with surface dew points of 16-17 °C and rather moist profiles throughout the troposphere. About 1000 - 1500 J/kg of MLCAPE should form in response to destabilization due to solar heating. With very weak winds throughout the profile, developing storms - that should be plentiful - will have difficulty organizing. The primary risk will therefore be local very heavy rainfall. Isolated wet downbursts and marginally large hail around 2, maybe 3 cm diameter will be possible too.

Bulgaria and Northeast Greece...

Ahead of the shortwave trough moving southeastward from Poland, a weak surface low will help to bring some low-level moisture inland from the Aegean Sea during the morning. The resulting level of humidity across Northeast Greece and South Central Bulgaria will help to create 500-1500 J/kg MLCAPE. Combined with moderate shear of around 15 m/s some organized storms with a risk of some 2-3 cm large hail will likely form.

Eastern Spain...

As moisture is brought inland by the diurnally occurring sea breeze, sufficient CAPE will build to sustain a few storms that are likely to trigger where the sea breeze is forced upslpoe onto the mountain ranges of eastern Spain. A combination of 1000-2000 J/kg of MLCAPE and 10-15 m/s deep layer shear should be sufficient to sustain a few very local but organized storms with a risk primarily of large hail, and to a lesser extent heavy rain and wind.