Storm Forecast
Valid: Sun 18 Oct 2026 06:00 to Mon 19 Oct 2026 06:00 UTC
Issued: Sun 18 Oct 2026 06:24
Forecaster: TUSCHY

A level 2 was issued across parts of the Gulf of Valencia mainly for excessive rain.

A level 1 surrounds the level 2 for an heavy rain, but also isolated tornado risk.

A level 1 was issued for far S Spain mainly for heavy rain and an isolated tornado risk.

A level 1 was issued across far SW France/NW Italy mainly for spotty heavy to excessive rain and an isolated tornado risk.

A level 1 was issued for SE Sardegna mainly for heavy to excessive rain.

SYNOPSIS and DISCUSSION

A pattern, rather favorable for heavy rain (at least on a regional scale) emerges atop the W Mediterranean during this forcast period.

Two distinct vortices over W/SW Europe make a Fujiwhara interaction, with the French one drifting W and the Spanish one more to the SW, later S. This pattern results in a broad area with lowered MSLP over SW Europe with a diffuse LL vortex sitting roughly in the DANA benchmark.
The main focus for extreme rain amounts evolves in the level 2 area, where cool/dried outflow from an extensive anticyclone over CNTRL Europe meets the moist/unstable S-erly flow, induced by the broad vortex over far SW Europe.
Transient spin-ups (LL vortices) are forecast to evolve along the zonally stretched out baroclinic/wind shift zone within the level 2. Background seems supportive with modest SW-erly mid-tropospheric flow to induce LL cyclogenesis somewhere E of E-CNTRL Spain, with not much net motion anticipated. This scenario is now better captured in latest IFS-ENS but we still see a modest zonal alignement in IFS-ENS members.

However, this scenario would not only induce a prolonged period with modest/moist/unstable onshore flow into the Valencia-Alicante area, but this could also induce temporal strengthening of the LLJ. Latest ICON output develops a potent 30-40 kt LLJ from the E/NE from the afternoon into the evening hours, which could result in a long-lived training V-shaped MCS event. Another secnario is a dominant offshore MCS, which drifts E towards the Balearic Islands along the marine front, which would lower the moisture content further W.

Uncertainties remain high, as a lot depends on the development of this mentioned pressure configuration, so nowcast trends will be important. Overall there is an enhanced risk for excessive rain within the level 2 and numerous significant flash flood events are possible. A few tornado events are possible,too.

We added another level 1 for S Spain to account for a few slow moving coastal storms, which bring heavy rain and an isolated tornado risk.

Two more level 1 areas were added for SE France/NW Italy and SE Sardegna. Dependant on mesoscale dynamics, like quasi-stationary convergence zones, numerous back-building clusters could evolve during the day with a local excessive rain risk. An isolated tornado along the coasts is possible.

A vigorous depression lifts N atop the Black Sea but limited time offshore should preclude any substantial LL warm core anomaly. Heavy rain and gusty wind with a few thunderstorms are forecast.