Storm Forecast
Valid: Fri 11 Jul 2025 06:00 to Sat 12 Jul 2025 06:00 UTC
Issued: Thu 10 Jul 2025 21:42
Forecaster: PUCIK
A level 2 was issued across parts of N Spain mainly for large to very large hail, heavy rainfall and severe wind gusts.
A level 1 surrounds the level 2 for the same threats but with smaller probability.
A level 1 was issued for NE Italy mainly for large hail and severe wind gusts.
A level 1 was issued for southern Carpathians mainly for heavy rainfall.
A level 2 was issued across NE Belarus, NW Russia, E Latvia and Estonia mainly for damaging wind gusts and large to very large hail.
A level 1 was issued across E Ukraine and SW Russia mainly for large hail and heavy rainfall.
DISCUSSION
... Spain ...
A low at mid to upper troposphere will slowly move eastwards during the day across the region, providing synoptic-scale lift at its forward flank. Closer to the surface, a dryline will establish between the lowlands and the highlands of the northern Spain with an upslope flow simulated during the late afternoon hours. Combination of this boundary and the local orography will provide the lifting mechanism for storms. The highest coverage is expected in late evening to overnight hours.
Forecast profiles reveal MLCAPE values ranging from 1000 to 3000 J/kg and 0-6 km bulk shear between 10 and 20 m/s. The best CAPE shear overlap is forecast in Zaragoza area, whereas the highest likelihood of storms is forecast near Bilbao. A variety of severe weather threats is forecast with storms. Earlier on, large to very large hail and severe wind gusts will dominate with heavy rainfall taking over later on as the storms grow upscale and the boundary layer becomes more stable. Lvl 2 is introduced in the zone where the highest coverage of severe weather is expected. Storms will spread east during the night and may eventually reach the coastline of Catalonia and exit over the sea.
... NE Belarus to Latvia and Estonia ...
A northwest-southeast oriented cold frontal boundary will become a focus for widespread thunderstorm activity during the day. A tongue of hot airmass with steep mid-tropospheric lapse rates will be advected ahead of the cold front from the continental Russia, overlapping with 12 to 14 g/kg of specific humidity close to the ground. This will yield high MLCAPE values reaching 2000 to 3000 J/kg. Much of the CAPE will be confined to the mid to upper troposphere. With strong warm air advection regime ahead of the front and combined with modest mid-tropospheric flow aloft, curved hodographs characterized by around 15 m/s 0-3 km shear and 150 to 300 m2/s2 SRH in 0-3 km layer are simulated.
First storms will be likely ongoing already in the morning hours, with rapid increase in coverage around 12 UTC. The first initiating cells may be supercells, capable of large to very large hail and severe wind gusts. With mean flow parallel to the front and shear confined to the bottom 3 km, a fast upscale growth is anticipated with one or two bow echoes developing and moving across the area. Expect widespread severe wind gusts and perhaps isolated gusts exceeding 30 m/s. Locally, damage can be exacerbated by the collocation of large hail and destructive wind gusts. This is a high-end Lvl 2 situation! Storms will decay towards late evening over northern Estonia and move over the Baltic Sea towards Sweden in elevated form with greatly reduced wind gust risk.
... E Ukraine to SW Russia ...
An increase in the coverage of storms is forecast in the late evening to overnight hours with some disagreement in models exactly where will be the storms most numerous. Storms will be elevated with their inflow layer starting around 1 km above the surface with available MUCAPE around 1000 J/kg and effective shear around 15 m/s. Large to perhaps very large hail and heavy rainfall will be the primary threats. A high end Lvl 1 is issued for the area.
... NE Italy ...
A subtle short-wave is forecast to cross the area in the afternoon hours, with cold mid-tropospheric temperature increasing the lapse rates below and yielding MLCAPE values around 1000 J/kg. With northerly flow aloft and southerly wind close to the ground, 0-6 km bulk shear values will increase to 15 to 20 m/s by the afternoon hours. Some supercells are likely to form, with one or two swaths of large hail and isolated severe wind gusts.
... Southern Carpathians ...
Weak mean wind combined with low LCLs and skinny CAPE profiles will yield an enhanced risk of locally very heavy rainfall in the mountainous areas of southern Carpathians in Romania.
