Storm Forecast
Valid: Mon 21 Jul 2025 06:00 to Tue 22 Jul 2025 06:00 UTC
Issued: Sun 20 Jul 2025 21:36
Forecaster: PUCIK
A level 2 was issued across N Italy to W Slovenia for severe wind gusts, large to very large hail and to the lesser extent for tornadoes.
A level 1 was issued across France mainly for tornadoes and severe wind gusts.
A level 1 was issued for Switzerland and SW Germany mainly for severe wind gusts and marginally large hail.
A level 1 was issued for NE Germany, W Poland and W Czechia mainly for heavy rainfall.
A level 1 was issued for Austria, E Czechia, S Poland and W Slovakia mainly for severe wind gusts.
A level 1 was issued for Russia mainly for heavy rainfall.
A level 1 was issued for NE Ukraine mainly for severe wind gusts and marginally large hail.
A level 1 was issued for Caucasus mainly for large hail.
DISCUSSION
... N Italy to W Slovenia ...
A complicated forecast to make for this area. It is likely that storms will already be ongoing across NW Italy in the early morning hours, both on the southern foothills of the Alps and the Ligurian coastline. Rainfall and cloudiness from this round of storms will likely reduce the chances for diurnal heating. As the storms spread east, cloud bases will remain rather low and boundary layer shallow. MLCAPE between 1000 and 2000 J/kg, combined with 0-6 km bulk shear between 20 and 25 m/s and 0-3 km shear around 15 m/s will allow for at least a couple of longer lived and intense supercells and/or small bow echoes capable of swaths of large hail and severe wind gusts. Isolated extremely severe event is not ruled out either. Degree of low-level shear is uncertain, but there will be a non-zero tornado threat particularly over the low-level convergence zone. While solid CAPE and shear will persist for the whole day over the area, drying mid-troposphere will start to limit chances of convective initiation from west. Because of this, following 12 UTC in the west and 15 UTC in the east, coverage of storms initiating over the convergence zone will remain isolated at best. Still, if storms can initiate,they will likely become supercells capable of severe weather.
... France to Switzerland and SW Germany ...
Scattered to widespread storms will initiate within a lifting trough. Across France, forecast profiles reveal curved hodographs with around 10 m/s of 0-1 km bulk shear and locally more than 100 m2/s2 of 0-1 km SRH. Stronger cells will be capable of tornadoes in this environment. As storms spread east to Germany and Switzerland, low-level shear will decrease, but deep-layer shear will increase. Severe weather threat will remain rather marginal given weak CAPE, absence of inverted-V profiles or prolific low-level shear. Still, Lvl 1 seems to be warranted, especially over Switzerland, where the strongest 0-3 km bulk shear is forecast.
... Austria, Czechia, Poland, Slovakia ...
A pronounced cold front will swing across the region with cyclogenesis along the front with a developing wave. North of the wave, over Poland and NE Germany, anabatic frontal circulation and parallel flow to the front will result in elevated storms training across the area with risk of very heavy rainfall. South of the frontal wave, the cold front will accelerate fast eastward, undercutting storms and clustering them into an disorganised squall line given lack of stronger shear. Still, as storms spread over the deep boundary layer east of the front, outflow will combine with strengthening low-level flow and result in isolated risk of severe wind gusts.
... Russia, NE Ukraine ...
Scattered to widespread storms will form within a cut-off low. Moist profiles and weak mean tropospheric flow point to the risk of heavy rainfall over Russia, whereas higher CAPE and stronger shear over Ukraine will yield risks of marginally large hail and severe wind gusts there.
... Caucasus ...
Isolated to scattered storms will initiate across the mountains. Forecast profiles reveal 15 - 20 m/s of 0-6 km bulk shear combined with modest CAPE, majority of which will be confined to the temperature below -10 deg C. Such environment will support large hail risk with stronger storms.
