Extended Forecast
Valid: Tue 07 Oct 2025 06:00 to Wed 08 Oct 2025 06:00 UTC
Issued: Sun 05 Oct 2025 12:18
Forecaster: TUSCHY

Two level 2 areas were issued across parts of S Turkey mainly for excessive rain.

A level 2 was issued for E Romania mainly for excessive rain.

A level 1 surrounds both level 2 for a similar hazard with lowered probabilities. In addition we expect an isolated tornado risk along the coasts.

A level 1 was issued for the N Aegean Sea mainly for an heavy rain and isolated tornado risk.

SYNOPSIS

The deep and anomalous strong upper trough (about to transform into a cut-off) over SE Europe dictates the weather over SE Europe and brings lots of rain. This trough gets framed by ridging to its W and N. Hence the thunderstorm probabilities stay confined to SE Europe.

DISCUSSION

... SE Europe ...

Placed beneath the upper low, an active day with thunderstorms is forecast for a broad area.

First the eastbound moving cold front over SW to S Turkey sparks a progressive MCS event, which brings heavy rain, gusty winds, some (small) hail and an isolated tornado risk along the coastal areas. We added confined level 2 areas, where orography forces BL flow to converge for a longer period with EPS/ENS data highlighting these areas with 24h rainfall amounts in excess of 100 l/qm. Excessive rain is forecast along the orography/coasts and flash flooding is possible. The progressive nature of this event however should limit the peak amounts.

Further W, beneath the upper low, slow moving/quasi-stationary convection occurs f.ex. over the N Aegean Sea with heavy rain and a few waterspouts, which equals a level 1.
Atop the Ionain Sea into the Sea of Crete, bands of convection bring bursts of heavy rain and an isolated spout risk. We opted to keep this below a level 1 for now due to the progressive nature of convection.

Romania into far N Bulgaria may see an heavy rain event with 24h totals in the 50-100 l/qm scale over a broad area. This however is not driven by upright convection but more through persistent isentropic ascent with embedded convective elements.
A different story for E Romania, where a strong E-erly flow regime advects an unstable (roughly 500 J/kg MUCAPE) and moist airmass (atop 1-2 K positive SST anomaly) onshore. Coastal convection stays near surface based and we could see a few training/backbuilding clusters over E Romania. Dependant on where these clusters start backbulding, we could see excessive rainfall amounts on a regional scale along the coast with 100-250 l/qm in less than 12h. Right now the ensemble/deterministic forecast pool is rather consistent in showing high amounts with good run-to-run consistency so we already added a level 2 for excessive rain. Flash flooding is possible with one or two significant events not ruled out (with and augmented general flood risk further inland - please refer f.ex. to GLOFAS for that risk).