Storm Forecast
Valid: Wed 09 Jul 2025 06:00 to Thu 10 Jul 2025 06:00 UTC
Issued: Tue 08 Jul 2025 21:49
Forecaster: TUSCHY

A level 2 was issued across Romania into SE Belarus for large hail, severe gusts and heavy rain.

A level 2 was issued across NE Belarus into Russia mainly for large hail, severe gusts, heavy rain and a tornado threat.

A level 1 surrounds both level 2 areas for similar hazards but with lowered probabilities.

A level 1 was issued for E Spain mainly for large hail, severe gusts and heavy rain on an isolated scale.

SYNOPSIS

The cut-off process over E-CNTRL into E Europe is in full process, ends its digging phase as the upper jet rotates downshear into the SE fringe of the trough and starts to lift from the Adriatic Sea E/NE towards N Romania/SW Ukraine until the end of the forecast. At the same time, height falls over the Baltic States point to another growing disturbance, which both merge into a broad N-S elongated cut-off over E/NE Europe.

A blocking anticyclone persists over far SW Russia with otherwise rising heights over the Mediterranean into W/NW Europe - the start of a very blocked pattern over Europe.

Along the eastern fringe of the upper trough numerous diffuse LL vortices cause a wavy surface front to bend either E (cold front) or W/NW (warm front). These vortices remain weak with ongoing broad IFS-ENS member spread of anticipated LL depressions (probably also affected by the convection from the previous night).

DISCUSSION

... Belarus into far NW Russia ...

A northward lifting weakening cluster affects Belarus before noon with some hail and rain issues. This activity is found beneath lowering geopotential heights along the periphery of one of the weak depressions, which lifts a pronounced warm front N. Especially the eastern fringes of that cluster see a moist and unstable inflow so we could see a few severe storms already before noon from E Belarus into Russia.

Thereafter, the main focus for organized DMC activity shifts towards a structuring triple point along an intersecting cold and warm front, which both merge into an occlusion, which bends W/SW towards NE Poland.
Impressive moisture pooling with mixed BL moisture in excess of 14 g/kg along the fringes of a pronouned EML push MUCAPE in the 2000 to 3000 J/kg range along the south side of the warm front with gradually decreasing values to the S/SE, where strong diabatic heating and WAA induce a deeply mixed BL.

CI within the cyclonic southerly flow regime occurs during the passage of weak mid-level IPV maxima and/or near enhanced BL convergence along the mentioned surface fronts. From noon onwards, expect a few discrete supercells to evolve from NE Belarus into W Russia with all kind of hazards like large hail, severe gusts and heavy rain as mentioned MUCAPE overlaps with 15 m/s DLS. Any storm, which moves along the southern fringe of the warm front experiences impressive low/mid-level shear with 0-3 km peaks in excess of 20 m/s not ruled out. Hence, the risk for bowing segments with swaths of damaging gusts are forecast. In addition, beside lingering capping issues, up to 300 J/kg LLCAPE and lowered LCLs also point to an isolated strong tornado risk. This activity spreads E/NE along the warm front deeper into Russia with an ongoing severe risk.

... Romania into SE Belarus ...

Rich BL moisture along the extensive N-S aligned wavy front remains mostly displaced from the steepest mid-level lapse rates, which is still enough for a belt of 800 to 1500 J/kg MUCAPE.
DLS is adequate for organized DMC activity and shear magnitude only increases from the SW during the day as the mid/upper jet maximum approach. Same for 0-3 km shear.
Expect scattered to widespread CI probably well before noon and long-lived and organized thunderstorms spread N/NE during te afternoon into the overnight hours. Swaths of severe to damaging gusts, large hail and heavy rain are forecast. The tornado risk is confined along the frontal boundaries, where LCLs lower and/or near any structuring LL depression.
Betimes, convection tends to cluster into numerous line segments as the activity shifts into Moldova and the Ukraine, where more widespread severe gusts and hail are possible.
An extensive level 2 was issued to cover this severe risk.
During the night, ongoing thunderstorms turn more elevated betimes with an heavy rain and hail risk.

... Spain ...

Onshore flow of a deep and very moist marine layer (emerging from the W Mediterranean, where positive SST anomalies in excess of 4 to 5 K exist) beneath steepened mid-level lapse rates along the orography cause weakly capped 1000 to 2000 J/kg MUCAPE. A brisk 15 m/s westerly shear affects this CAPE plume, which ensures any growing updraft to become organized. A layer of dry air above 600 hPa may cause entrainment issues, so growing updrafts probably struggle for some time. Finally, merging updrafts could produce a few longer lived cells (organized multicells and maybe a temporal supercell) with large hail, severe gusts and heavy rain on a local scale. We kept this in a level 1 although we cannot rule out an isolated extreme event (hail).

... S Sweden ...

A few afternoon thunderstorms bring strong gusts in a well mixed BL environment next to heavy rain on an isolated scale.