Storm Forecast
Valid: Thu 09 Oct 2025 06:00 to Fri 10 Oct 2025 06:00 UTC
Issued: Wed 08 Oct 2025 06:34
Forecaster: TUSCHY

A level 1 was issued for SE Spain and offshore areas mainly for heavy rain and an isolated waterspout event along the coasts.

A level 1 was issued over the Gulf of Alexandretta for an isolatd gust, heavy rain and tornado risk.

SYNOPSIS

The long-lived upper trough over SE Europe lifts NE towards the Black Sea in response to an approaching and digging trough over Scandinavia. In the meantime a SW-NE aligned upper trough evolves over SW Europe and results in an increasing thunderstorm risk over parts of SW Europe. Initial modest CAPE increases during the following days, which increases the excessive rain risk over E Spain.

DISCUSSION

No major changes were needed when switching this forecast from SWODY2 to SWODY1 (SWODY = severe weather outlook day).

SE Europe will see good thunderstorm coverage over a broad area. However only one focus for more organized thunderstorm activity exists and this area is still highlighted with a level 1. A passing strong upper trough should induce scattered thunderstorms, which can organize in adequate shear but only modest CAPE. In addition, rather weak LL lapse rates should keep the general severe risk in check. Expect a few heavy rain, gust and even an isolated tornado event with the strongest activity. The risk ends during the evening hours from the W.

No major changes also to the level 1 over SE Spain. The core of the upper vortex shifts from NE Spain to the SE towards the Balearic Islands before drifting S during the day. Along the BL, no real mass response can yet be expected, although a 40 m/s 250 hPa upper jet core over S Portugal/far SW Spain helps to lower the MSLP over S Spain on a slow pace during the day. This synoptic evolution does not yet assist in a focused/long-lived/confluent BL onshore flow event. However with rising surface pressure over NE Spain, we see at least numerous episodes of onshore flow, where convective coverage increases within the level 1 area. One peak is forecast from 06Z onwards into the early afternoon hours mainly in the provinces Valenica and N Alicante with a second round beyond midnight.

A residual plume of enhanced TPWs (around 30-35mm) combined with weak mid-level lapse rates creates elongated/rather skinny CAPE profiles. Repeated onshore moving clustering and rather disorganized thunderstorms bring heavy rain and a few very heavy amounts in excess of 100 l/qm/24h are possible - mainly over the province of Valencia. A few flash flood events are possible but the rather disorganized nature of onshore flow and the lull in activity between late afternoon until midnight with EPS peaks mostly around and less than 100 l/qm/24h keep this event in a level 1 right now. Ibiza was added to the level 1.

Please refer to the SWODY2 discussion below for more information.

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... SE Spain and the far W Mediterranean ...

Advection of a marine airmass from the E beneath the structuring upper trough offers a broad area with 500-1000 J/kg SBCAPE offshore and lowered onshore values over SE Spain. DLS remains weak to moderate with 5-10 m/s, so rather disorganized thunderstorm activity is anticipated. Repeated CI along mesoscale convergence zones near the coast cause scattered thunderstorm coverage throughout the day and we could see a few rainfall peaks in the 50-100 l/qm/24h range but mainly offshore and very localized. However this onshore moving convection can also pose an heavy rain risk and parts of SE Spain were upgraded to a level 1. A few waterspouts are possible, too.

A weak upper jet maximum crosses N Algeria/Tunisia E during the day and a weak/diffuse LL vortex is forecast beneath its left exit just S of Sardegna. This would induce a broad confluent wind field S/E of Sardegna with an uptick of convection during the night. Local heavy rain and an isolated waterspout is possible but not yet enough for a level 1.

... SE Europe ...

The filling and NE ward lifting upper trough induces a broad area with active thunderstorm coverage. Strong SW-erlies along its S fringe affect the Gulf of Alexandretta with 20 m/s DLS and adequate CAPE for a few organized thunderstorms with gusts, hail and heavy rain. A confined level 1 was added and this risk ends until the evening.
Over the E Black Sea, strong shear overlaps with modest SBCAPE, but adiabatic warming of descending air downshear of N Turkey adds a low-tropospheric cap, so not much organized convection is forecast. Heavy rain however is possible along the coastal areas of the E Black Sea. This is also true for the Kure Escarpment just N of N-Turkey, where persistent onshore flow offers some healthy rainfall amounts. Latest QPF peaks won't support a level 1 for those areas but these areas will be monitored for potential upgrades.