Storm Forecast
Valid: Mon 18 May 2026 06:00 to Tue 19 May 2026 06:00 UTC
Issued: Sun 17 May 2026 12:59
Forecaster: TUSCHY

A level 2 was issued for N Belarus into E Latvia for large hail, strong to severe gusts and a few tornadoes.

A level 1 surrounds the level 2 with similar hazards including heavy rain.

A level 1 was issued for parts of NE Italy mainly for some hail, gusts and an isolated tornado.

A level 1 was issued for E-Armenia into Azerbaijan for large hail and gusts.

SYNOPSIS

A negative tilted trough gets entrenched between blocking anticyclones over NW Russia and SW Europe and fractures into numerous confined upper vortices.

A NW-ward surging warm front, which evolves into cold/warm fronts next to a structuring depression becomes the main area of concern for DMC activity over NE Europe.

DISCUSSION

... N Belarus into E Latvia and adjacent regions in W Russia ...

A substantial short wave lifts NW into the Baltic States and distorts an accompanying warm front into warm/cold front next to a rather strong 1005-1010 hPa LL vortex, which is well clustered in IFS-ENS data. Strongest CAPE build-up occurs downstream of the wave, as cooling mid-levels overspread a plume with maximized BL moisture near the apex of the distorted front (narrow but well defined warm sector). A meridionally elongated warm sector evolves betimes with a quasi-stationary (shear parallel) cold front and a lifting warm front. This increases residence time of updrafts in the unstable airmass as convection shifts N/NW.

A confined overlap of strong CAPE and shear evolves in the highlighted area with only the afternoon hours left for near uncapped/slightly capped conditions. MUCAPE in the 1000-2000 J/kg range and 15/20 m/s 3/6 km shear with strongly looped hodographs highlight a rather volatile environment for organized multicells/supercells. Any cell, riding the warm sector to the NW poses a large hail and severe to damaging gust risk. Storms, which ride along the fronts also pose a tornado risk with a strong event not ruled out.

Further S into S Belarus, modest CAPE/shear space remains in place but will be capped (slightly) with weak ridging aloft. CI will be possible, but long-lived DMC activity is less likely also due to widespread CI and/or clustering convection next to the trailig cold front. Anyhow, any more discrete and better structured cell could pose all kind of hazards including an isolated tornado.

The level areas were broadened to reflect ongoing modest issues with the depression's final strength and track but also the uncertainty, how far E the convection evolves along the warm front itself.

... N Italy ...

An upper trough sheares off atop the area of interest with one part crossing Benelux NE and the other one dropping S towards the CNTRL Mediterranean. This pattern induces transient/weak MSLP fall over N Italy as a diffuse vortex/wave organizes just E of the N Apennines before dissolving thereafter - with only low-end representation in IFS-ENS data.

This scenario assists in temporal onshore advection of a marine airmass with 2m dewpoints in the lower to mid tens. Resulting confined plume of 800-1500 J/kg MUCAPE affects NE Emilia-Romagna into S Veneto with up to 15 m/s DLS intersecting this area. A few multicells and isolated supercells pose an isolated large hail and strong gust threat with an isolated tornado not ruled out in the vicinity of the marine front itself. Thereafter, a slightly capped MUCAPE plume spreads also NE into E Veneto and S Friuli-Veneza-Giulia with an ongoing isolated hail and gust risk. Decreasing CAPE3 lowers the tornado risk further.

During the afternoon onwards, numerous storms also evolve into E Lombardia but CAPE/shear space seems to be to marginal for anything severe. Still some strong cold pool gusts and isolated hail could spread into W Veneto during the evening.

... E-Armenia into Azerbaijan ...

Modest DLS on the order of 15 m/s overspreads better BL moistue with MUCAPE up to 1500 J/kg, so large hail and numerous gusts are forecast.