Storm Forecast
Valid: Tue 01 Jul 2025 06:00 to Wed 02 Jul 2025 06:00 UTC
Issued: Mon 30 Jun 2025 17:16
Forecaster: TUSCHY

A level 1 was issued for parts of CNTRL Europe mainly for strong to severe downbursts, a few large hail events and heavy rain.

SYNOPSIS

A blocking ridge remains in place from CNTRL Europe into Scandinavia and gets framed by a broad cut-off over W Russia and a progressive trough over the far NE Atlantic. No synoptic-scale front impacts today's DMC activity.

DISCUSSION

... SW Germany to Switzerland and NW Italy ...

Despite the placement beneath the strong upper ridge, highest thickness values to the N and a weak passing IPV maximum add some thunderstorm probabilities to this area. This disturbance exits E-France into Switzerland during the day and later-on into NW Italy during the night.

A combination of strong diurnal heating with some synoptic-scale lift along the IPV's periphery should support scattered to widespread CI mainly along the orography, before this activity moves into the lowlands.

Initiating cells pose a hail risk with isolated hail up to 4-5 cm in diameter not ruled out, as pockets of 1-2 kJ/kg MUCAPE offer rather thick mid-level CAPE profiles. Despite weak DLS (mostly 10 m/s or less), broadening updrafts with elongated hail paths in the flanking lines/updraft core could produce a few large hail events. Heavy rain along the orography or next to colliding updrafts is also forecast.
Otherwise heavy precipitation load and lots of CAPE above lower-tropospheric inverted-V profiles indicate a risk of numerous strong to isolated severe downburst events. Clustering convection could temporarily support swaths of hail and severe gusts. The activity weakens around sunset with increasing CIN, although a few clusters could survive well into the overnight hours.

... England to Denmark and S Norway ...

A WCB starts to interact with a northward fanning EML, so expect regionally enhanced nocturnal thunderstorm activity with some graupel and heavy rain.
SE-UK needs to be monitored for isolated CI during the late afternoon, where weak CIN in weak background forcing persist. Right now, surface based CI is not forecast but not much BL modification is needed for isolated CI. Strong shear would support updraft organization but low confidence in this scenario precludes an upgrade for now. High prob. lightning area covers some elevated activity during the night.