Storm Forecast
Valid: Thu 30 Jul 2026 06:00 to Fri 31 Jul 2026 06:00 UTC
Issued: Wed 29 Jul 2026 11:09
Forecaster: TUSCHY

A level 2 was issued for parts of N Germany mainly for severe to damaging gusts.

A level 1 surrounds the level 2 for similar hazards with lowered probabilities. In addition isolated hail is forecast.

A level 1 was issued for parts of Norway and Sweden mainly for an isolated tornado risk but also for severe gusts, hail and heavy rain.

A level 1 was issued for parts of W Russia mainly for large hail, heavy rain and gusts.

SYNOPSIS

A baroclinic ridge resides over most parts of Europe which turns barotropic towards far SW Europe. The main event for this forecast will be the interaction of a strong trough over the Norway Sea with the mentioned ridge, creating a tight mid/upper height gradient over W-CNTRL into NW Europe. A potent lead impulses/low-amplitude waves race NE from France to Germany, creating a corridor with enhanced severe probabilities.

DISCUSSION

... Norway to Sweden ...

*** Update ***
Not much change compared to the extended outlook. A sheared and unstable warm sector will see scattered CI mainly near the cold front but also at least isolated within the open warm sector. The last-mentioned coverage depends on subtle short waves and more discrete CI is possible.

Any more discrete cell within the warm sector should rotate with a tornado, severe gust, hail and heavy rain risk. Convection near the stalling cold front has the tendency to more rapid upscale growth with near parallel alignement of shear and translation vectors. Strong LL shear and adequate MUCAPE assist in a severe risk with all kind of severe possible. We expanded the level 1 towards W Finland to acount for a few better organized cells especially for cell motions to the SE. Again, an isolated tornado, some hail, heavy rain and gusts will be the main hazard.

*** Previous discussion ***

A N-ward surging warm front stretches out an extensive warm sector, which features an unseasonable moist low/mid troposphere beneath somewhat enhanced mid-level lapse rates. Placed along the exit of a potent NE-ward surging upper jet, a diffluent and partially divergent upper flow overspreads the warm sector, although no clear DPVA maximum is seen during the day.

Admit at least temporal diabatic heating, expect an extensive plume of 500-1000 J/kg MUCAPE, affected by augmented kinematics. Point source soundings show 15-20 m/s DLS and up to 15 m/s 0-3 km shear. Ongoing WAA regime also assists in augmented helicity and forecast hodographs reveal curved signatures with abundant 0.5/1 km streamwise SR inflow. A weakening of the mid/upper flow regime hints at potential destructive interference of rapidly growing downdrafts with any inflow, pointing towards the updrafts. Any more discrete cell could rotate and low LCLs point to a tornado risk next to severe gusts, heavy rain and some hail.

The main limiting factor will be the early departure of a lead impulse with not much lift from the synoptic-scale during the day. During the night, lift increases once again as the main trough approaches from the SW.

We kept this in a level 1 due to potential limited thunderstorm coverage. Any longer lived cell could become severe and we monitor following NWP runs, if a more focused severe risk area evolves.

... France to Germany ...

*** Update ***

Forecast philosophy remains more or less on track. The strong short wave has persistent forecast performance regarding geometry, track and speed in NWP data with latest cross sections still indicating an healthy PV tower. Attendant mid-tropospheric wind response with H7 winds in the 50-60 kt range pushes 0-3 km shear into the 20-25 m/s range. The saving grace will be a 150-200 km displacement of this intense low-tropospheric shear to the initiating convection, which probably precludes a derecho event. If we get CI closer to the wave, a focused corridor with very severe gust reports would be possible like over Lower Saxony. Nowcast will be needed to estimate this potential risk.

Nevertheless, 15 m/s 0-3 km shear overlapping with DCAPE in the 800-1300 J/kg range and 500-900 J/kg elevated MUCAPE will be enough for a more focused (DMC driven) severe gust risk over parts of N Germany and a few extreme gusts in excess of 30 m/s are possible. A risk of clustered severe gust reports prompted the level 2 upgrade also driven by its high impact for this time of year. Isolated hail is possible.

Although not covered by our risk scheme, we also mention the risk of fire ignition with a few dry thunderstorm events, impact by wind driven dust transport and a prolonged period of enhanced gusts due to the passing speed maxmum behind the convection in a partially capped airmass.

No change for the rest of the outlook.

*** Previous discussion ***

This area sees a perfectly timed short wave passage. PVU cross sections trough this wave show a robust PV tower, which extends deep into the troposphere and activates an healthy (a)geostrophic wind response into the 600/800 hPa layer.

This wave interacts with a well mixed/dry BL, where 2m dewpoints hover in the lower single digits. Steep mid-level lapse rates and the synoptic-scale lift induce elevated convection, which starts over CNTRL France from the morning onwards before spreading NE.

There are two options right now as convection approaches Germany:

a) NE-ward spreading elevated convection induces an outflow, which outruns the wave and lowers chances for thunderstorm activity. This results in a broad corridor with potential gale-force gusts and a few severe gusts.

b) The wave interacts with better BL moisture, which advects from Benelux E. This scenario would place a growing cluster of thunderstorms ahead of the wave. A potent 25 m/s 0-3 km shear vector along the wave's tip (attached to the deep PV tower) would point normal to this thunderstorm activity, assisting in rapid upscale growth of convection. DCAPE in the 1500 J/kg range and the mentioned kinematics could favor swaths of damaging gusts with numerous events in excess of 30 m/s possible and even a progressive derecho event cannot be ruled out.

Right now, we kept this in a broad level 1. The added high probability lightning area over W-CNTRL to N Germany is roughly the region, where a wind-driven level 2 upgrade with high impact seems possible. We still wait for more EPS data of CAMs to define the final gust risk. Isolated hail is also possible.

... W Russia ...

1500 J/kg MUCAPE and weak shear assist in clustering convection with isolated large hail, heavy rain and strong gusts. A broad level 1 was added.