Storm Forecast
Valid: Tue 15 Jul 2025 06:00 to Wed 16 Jul 2025 06:00 UTC
Issued: Mon 14 Jul 2025 22:58
Forecaster: PISTOTNIK

A level 1 is issued for Denmark and southernmost Sweden for excessive convective precipitation.

A level 1 is issued for parts of Russia, Estonia, Lithuania, E Poland, Belarus, the W Ukraine and parts of Romania mainly for excessive convective precipitation and, to a lesser degree and mainly towards the E and SE, for large hail and severe convective wind gusts.

A level 1 is issued for parts of Germany, SW Poland and the Czech Republic mainly for severe convective wind gusts and to a lesser degree for excessive convective precipitation, large hail and tornadoes.

A level 1 is issued for parts of Turkiye and Georgia for large hail and to a lesser degree for severe convective wind gusts.

SYNOPSIS

The two dominant players are a blocking anticyclone between Iceland and W Russia and a cyclone that slowly moves from the British Isles to the North Sea. Slightly lower 500 hPa geopotential also extends east- and southeastward towards Belarus and the Black Sea. At the southern flank of this extensive mid-level low, a strengthening W-erly to NW-erly flow covers most of W, central and SE Europe. While clear synoptic fronts are missing, cooler Atlantic air makes a slow SE-ward progress, gradually also easing the heatwave in the W and central Mediterranean basin and the Balkans to some degree.
Hot and qiuescent conditions continue in Iberia, Turkiye and Russia, from where a stream of very warm air extends also far NW-ward into central Scandinavia.

DISCUSSION

... between S Scandinavia, W Russia and Romania ...

A number of areas in the range of the extensive mid-level low and at its forward flank see low to regionally moderate CAPE with expected maxima up to 1500 J/kg. Deep-layer shear is mostly below 10 m/s. Scattered to widespread, largely daytime-driven thunderstorms are expected to initiate at numerous sources of meso- to small-scale lift: a long and stalling frontal boundary all the way from S Norway into Russia separating cooler maritime air to the SW from warmer continental air to the NE, outflow boundaries, sea breeze fronts in coastal areas, orographic circulations in Romania, countless small travelling vorticity maxima aloft, and last but not least the converging wind field near the cyclone's center in Denmark and southernmost Sweden. Thanks to weak vertical wind shear, slow storm motion and a regionally high storm coverage, excessive rain is the main hazard. Stronger pulse storms can also produce isolated large hail and severe downbursts, mainly towards the E and SE (i.e., Russia and Romania), where somehwat steeper lapse rates are present. Since the initiation mechanisms seem less concentrated than on Monday and the model pool disagrees on possible "hot spots", a broad level 1 seems to be the best solution. Some regions could see a severe weather density high enough for a level 2, though.

... central Europe ...

Another pronounced short-wave trough crosses Germany, W Poland, the Czech Republic and Austria from WNW to ESE, though its lift is partly compensated by cold air advection. Meager lapse rates but adequate low-level moisture create CAPE up to 800 J/kg after some hours of daytime heating. Scattered thunderstorms form in the afternoon to evening. The strengthening wind field raises vertical wind shear to 15-20 m/s across the 0-6 km layer and around 10 m/s across the lowest kilometer in the course of the day. Convection will therefore likely organize into low-topped multicells and probably some transient supercells or bowing line segments. Severe wind gusts are possible with the best organized storms, along with locally excessive rain and marginally large hail. Due to enhanced low-level shear and low cloud bases, one or two short-lived tornadoes are not ruled out.

... Turkyie, Georgia ...

Scattered afternoon and evening storms will form under moderate CAPE and moderate vertical wind shear, primarily over orographic features, and organize into multicells and perhaps a few supercells. Large hail and a few downbursts are possible, especially when storms manage to detach from the mountains and break the capping inversion to ingest the more plentiful CAPE over lower terrain. Since this scenario is a bit questionable under very limited synoptic lift, two small level 1 areas seem to suffice.