Storm Forecast
Valid: Tue 18 Nov 2025 06:00 to Wed 19 Nov 2025 06:00 UTC
Issued: Mon 17 Nov 2025 10:14
Forecaster: TUSCHY

A level 2 was issued for parts of SW Italy but also for the S Adriatic into the NE Ionian Sea and parts of Montenegro into Albania for locally excessive rain and severe gusts. A strong tornado event is possible but also a few large hail events in the eastern level 2.

A level 1 surrounds the level 2 areas with similar hazards but lowered probabilities.

A heavy rain level 1 was issued for NW Greece into SW Bulgaria.


SYNOPSIS

An extensive cyclonic gyre over Scandinavia stretches out a positive tilted trough all the way towards CNTRL/SW Europe. A digging 130 kt upper jet keeps the tilt rather stable during the forecast with not much net-motion forecast. Numerous embedded low-amplitude waves along its periphery modify the thunderstorm risk on a regional scale with the main ingredient peak over parts of the Ionian/Adriatic Sea.

DISCUSSION

... Italy to Montenegro and Albania but also far NW Greece to SW Bulgaria ...

The static geopotential height pattern results in a prolonged severe risk for this area.

A warm/moist airmass from the S advectes beneath a strong southwesterly jet, which results in a broad CAPE/shear overlap. Parts of the Tyrrhenian Sea and the S Adriatic Sea will see 500-1000 J/kg MUCAPE and 35-55kt DLS. S of Italy and atop the Ionian Sea, steeper mid-level lapse rates improve MUCAPE into the 1000-2000 J/kg range while DLS stays more or less the same.
A thermal ridge beneath the EML induces weak capping for most of the Ionian Sea/Gulf of Taranto but a gradual cooling trend from the NW also increases the offshore thunderstorm risk during the night.

All of the mentioned areas see a risk of organized multicells and numerous discrete supercells with all kind of hazards.
An high-end level 1 was issued for the SE Tyrrhenian Sea and a local upgrade for parts of Campania was performed due to an augmented risk of numerous supercells until the early afternoon hours with an isolated tornado, severe gust and heavy rain risk.

The main focus for mode widespread severe exists from Montenegro S to Albania. Hodographs reveal impressive signatures offshore and along the coasts with plenty of LL helical inflow into near surface based V-shaped clusters with a strong tornado and severe gust risk next to excessive rain with slow moving or back-building clusters.
NWP guidance also points to the passage of a 700 hPa thermal trough, which steepens mid-level lapse rate with an increasing large hail risk. This however also results in less curved hodographs, which could lessen the risk of discrete cells a bit. Nevertheless a substantial severe risk is forecast.

The onshore severe risk depends a bit on temporal diabatic heating. Not much BL modification is needed for near surface based activity and hence the level 2 was drawn well inland for now. Models diverge with the onshore severe risk with some indicating elevated and less severe activity and others at least a regionally enhanced severe risk. Nowcasting of the BL will be very important.

We upgraded far NW Greece into SW Bulgaria for an heavy rain risk with bands of NE-ward moving convection. Local very heavy rain is forecast with 100 l/qm/12h peaks over SW Bulgaria not ruled out (Rhodopes).

... S-North Sea and adjacent areas ...

A broad mid-level wave crosses UK to the SE during the forecats period. It approaches a more focused thermal gradient over SE UK, which results in a structuring surface wave. It moves offshore and towards Benelux during the night. Some diabatic support is forecast with vigorous shower and some thunderstorm activity in the wave's periphery. Graupel and some gusts are forecast.
The warm-up of the vortex'core could result in a weak shallow warm-core setup with enhanced BL wind response. This could bring strong to severe gusts to the coasts of East England and less intense also to the coasts of the Netherlands and Belgium. This however does not justify any level upgrade.

Another uptick in convection occurs upstream over parts of the N-North Sea but nothing severe is forecast (despite strong to severe gusts offshore).