Storm Forecast
Valid: Tue 28 Oct 2014 06:00 to Wed 29 Oct 2014 06:00 UTC
Issued: Mon 27 Oct 2014 23:08
Forecaster: PISTOTNIK

A level 1 was issued for the Ionian Sea and southern Greek coastlines for excessive precipitation and (supercellular) tornadoes.

A level 1 was issued for parts of the Aegean Sea for (non-supercellular) tornadoes.

SYNOPSIS

To the south of a steering cyclone over the Arctic Sea, a strong zonal flow stretches from the British Isles across Scandinavia into Russia. Very warm air is advected east- to northeastward in the broad warm sector, followed by a cold front and a vorticity anomaly which enter Scotland, Norway and Sweden in the course of the forecast period.
The rest of Europe is dominated by high pressure with rather cool and dry air, though a diffuse and inactive upper-level low can still be found over the Balkans.

DISCUSSION

... Mediterraean Sea ...

Weak and cool northerly to easterly flow on top of a rather warm sea surface creates neutral to slightly unstable profiles over much of the Mediterranean Sea. Mostly this occurs under limited vertical wind shear. Apart from a possibility of isolated waterspouts (most notably over parts of the Aegean Sea), the severe weather risk is low.
The only more interesting setup is tied to an ill-defined surface cyclone that moves eastward over the Ionian Sea. At its forward flank, 0-3 km shear and storm-relative helicity may be enhanced to ~15 m/s and ~200 m^2/s^2, respectively. Most of the convection will stay over the open sea and will likely be too clustered for a better organization of individual storms. However, the islands and coastlines of southern Greece may increasingly be affected towards evening and overnight. One or two tornadoes are possible, along with heavy rain with a threat of localized flash floods.

... Norwegian Sea ...

Low-end CAPE will build up in a well-mixed polar air mass postfrontal air, but distinctly behind the strong wind field and strong shear regime of the warm sector and (non-convective) cold front. Expect a few showers to grow deep enough to produce a little lightning, especially overnight.