Storm Forecast
Valid: Wed 18 Jun 2025 06:00 to Thu 19 Jun 2025 06:00 UTC
Issued: Tue 17 Jun 2025 11:16
Forecaster: TUSCHY

All level 1 areas see a risk of heavy rain, isolated hail and strong to severe downburst gusts.

SYNOPSIS

Quiescent conditions persist for most of Europe as a blocking ridge remains centered over SW into CNTRL and SE Europe. A cut-off exits CNTRL Italy to the SW as it shifts gradually towards the Strait of Sicily.
A progressive pattern evolves over NE Europe between lowered geopotential heights over Scandinavia, which face the mentioned blocking ridge.

Numerous progressive fronts cross far NE/E Europe into Russia and they carry a scattered thunderstorm risk over a broad area. otherwise no synoptic-scale front adds to the DMC activity over Europe.

DISCUSSION

... SE Spain ...

Weak onshore flow advects a roughly 500 m thick moist marine layer ashore with 2m dewpoints in the lower twenties, decreasing onshore. Most of the airmass remains capped despite isolated to scattered convection along the orography. Decent MUCAPE of roughly 1500 J/kg is adequate for a temporal hail risk with initiating convection before clustering pushes heavy rain on a local scale in the foreground next to a few strong downdraft gusts. The activity weakens after sunset.

... Tyrrhenian Sea and surroundings ...

A slow moving upper low (only very weak imprints in EZ-ENS for a BL spin-up) crosses the mentioned area to the S. Onshore advection of a very moist/unstable airmass towards SW Italy sparks scattered to widespread thunderstorms. BL dewpoints remain in the lower twenties but also mid/upper levels see abundant moisture from the S (connection all the way to the tropics), so the main risk will be very efficient rainfall rates with possible flash flooding. Initiating cells could locally bring some hail and strong downdraft gusts.

Sicily will see 1000-2000 J/kg MUCAPE and 0-6 km shear up to 15 m/s with otherwise weak winds at mid/lower levels. Convection with better upper ventilation could support numerous slow moving thunderstorms with very heavy rainfall rates and isolated hail/strong downburst gusts.

A few waterspouts are possible offshore/along the coasts.

...Albania to Montenegro ...

Diurnal driven scattered convection with slow storm motions poses a low risk for some hail, strong downdraft gusts and heavy rain. A low-end level 1 was added. Convection weakens beyond sunset.

... Lightning areas ...

Scattered to widespread CI occurs over NE Europe into Russia but either weak shear or CAPE or both keep the severe risk below severe criteria.
CNTRL/E Belarus could see strong gusts and an isolated tornado with peak convection beyond noon but marginal CAPE precludes an ugprade for now.