Storm Forecast
Valid: Wed 01 Jul 2026 06:00 to Thu 02 Jul 2026 06:00 UTC
Issued: Wed 01 Jul 2026 02:06
Forecaster: TUSCHY

A level 2 was issued for parts of Poland, N Slovakia and E Czechia mainly for severe to damaging gusts, excessive rain and large to very large hail.

A level 1 surrounds the level 2 with large hail, strong to isolated severe gusts and heavy rain. A few extreme events are possible. In addition, an isolated tornado is possible along the coastal areas of N/CNTRL Italy, also over N-CNTRL Germany and over CNTRL Poland.

SYNOPSIS

We still deal with some zonal fave flux from the W, converging into the blocking pattern over Europe but with divergent signatures over E Europe (resulting in a weakening ridge pattern there) and ongoing convergence over SW Europe (increasing thickness there). With this westerly energy, a pronounced upper trough drifts from CNTRL into NE Europe while getting sheared apart with IPV data indicating lots of energy transfer towards a structuring cut-off over the W Alps/far NW Italy, which drifts towards Corse during the night.

In the meantime, a broad vortex over SE Europe opens up into an extensive trough with lowered height anomalies from the CNTRL Mediterranean E towards the Balkans, resulting in a broad area with tunderstorm probabilities.

A meridional aligned wavy boundary over CNTRL Europe drifts slowly E with an extremely moist and unstable airmass ahead (augmented EFI MUCAPE over E-Europe and positive TPW anomalies in excess of 200-230% or 35-45 mm over most of CNTRL into E Europe).


DISCUSSION

The stage is set for an active day with widespread thunderstorm activity over most parts of CNTRL/E into S Europe. The combination of abundant upper divergence along the periphery of the southward dripping energy and the very moist and unstable airmass create a favorable background for large and long-lived clusters to affect the highlighted area.


... Level 1 and 2 areas ...

Not much details need to be worked out as partially erratic thunderstorm/cluster motions are prone of creating rather messy looking tracks with lots of cell-cell interactions - hard to forecast any details that far out.

On the broader scale, we start with an intensifying and growing cluster from Switzerland into SE/E Germany beneath abundant upper divergence. This activity tracks E/SE towards lowered MSLP and into the unstable/moist airmass although storm-scale dynamics like regional bowing/RIJ segments could cause a wavy pattern betimes of this extensive MCS. Excessive rain will be the main risk next to some hail and strong gusts.

As this convection shifts further E towards Czechia/Austria into Poland, MUCAPE (already impressive) undegoes its diurnal increase and peaks in the 2500-3500 J/kg range.

The latest idea is that the MCS remains progressive over Czechia into Poland, which is caused both by lowering MSLP towards Poland (IFS-ENS indicating a weak/diffuse LL vortex spin-up) but also due to the eastward shifting IPV lobe/upper trough. In addition, this cluster most likely turns into an extensive MCV event, which itself pushes the line constantly E into Poland.
Both, internal dynamics and a steadily improving CAPE/shear space support a long-lived severe MCS event, which intensifies over N/CNTRL Czechia before racing into Poland, where 3km and 6km bulk shear increase to 15 and 20 m/s, respectively. Swaths of damaging gusts with large hail and excessive rain are forecast and a level 2 was added, although uncertainties remain, if the MCS tracks more into the S or CNTRL part of the level 2 area or if destructive interference of MCS activity lowers the overall risk. Despite rather stable BL, we could see a confined area with better LLCAPE and strong SRH1 overlap, so a tornado event is possible.

In addition, we expanded the level 2 into E Czechia, N Slovakia and towards SE Poland to account for a favorable CAPE/shear space, which supports severe multicells/a few supercells with very large hail, severe gusts and excessive rain.

We expanded the level 2 into SE Lithuania/NW Belarus for a growing excessive rain risk with slow moving/clustering convection.

A weakness in activity is possible over SE Czechia into E Austria due to limited lift out of the synoptic-scale as the main lobe of energy drops S towards Corse. Nevertheless, an extensive outflow from this cluster runs into the mentioned high CAPE environment over E Europe with otherwise well know CI mechanism like a diurnal weakening of the cap and CI along the orography towards the W Balkans. Expect intense updrafts with an initial large hail, excessive rain and severe gust risk. Numerous erratic moving clusters could bring confined swaths of severe and clustered severe reports are well possible. Although we keep this activity in a general level 1 area, we highlight the chance for a few very large hail and extreme rainfall events, driven on the mesoscale (e.g. by merging cells with broadened updrafts or cell interaction with the orography).
In addition we could see a pressure wave exiting far SE Germany into E Austria with strong to severe gusts.

Italy starts the day with another round of intense thunderstorms along the orography, which spread offshore betimes. A general uptick in activity is forecast during the night from the NW with the approaching IPV maximum and a large cluster of thunderstorms could cross N-CNTRL Italy to the SE with heavy to isolated excessive rain, hail and gusts. An isolated coastal tornado event is possible. Please be aware of dangerous offshore winds even without thunderstorm activity for the Ligurian and N/CNTRL Adriatic Sea during the night.

N Germany could see an isolated tornado risk with better CAPE3 next to heavy rain and some graupel/hail beyond noon into the afternoon hours.