Storm Forecast
Valid: Mon 28 Nov 2016 06:00 to Tue 29 Nov 2016 06:00 UTC
Issued: Sun 27 Nov 2016 23:56
Forecaster: VAN DER VELDE

A level 2 was issued for the northeastern Aegean Sea region mainly for excessive convective rainfall and tornadoes.

A level 1 was issued for Albania and Greece mainly for isolated excessive convective rain and tornado chances.

A level 1 was issued for E Spain, Balearic islands and SW Mediterranean Sea mainly for excessive convective rain and waterspout type tornadoes.

SYNOPSIS / DISCUSSION

At the surface level a strong high pressure system has installed over the North Sea with a stabilizing effect on an area between Ireland, central Scandinavia to the Alps. Cold air spreads into central Europe from Scandinavia. In mid/upper levels a large scale advances through the Balkan and Ukraine with strong dynamic lifting.
A weaker extension of this trough over the Mediterranean is responsible for unstable weather. In the western Mediterranean vertical wind shear and horizontal flow are weak, so that convection could produce excessive rain with chances of flash floods when they occur over land (e.g. eastern Spain, Balearic Islands), while these conditions are favorable also for waterspouts.
Albania and western Greece will have most convective activity in the morning with isolated excessive rain events possible. Vertical shear is enhanced early on with values supporting tornadoes. The focus shifts rapidly toward the northern Aegean Sea, NE Greece and NW Turkey coasts, where a cold front from the European mainland pulls in high moisture and temperatures into a narrow zone which appears to affect NW Turkey for a long time, with significant chance of excessive convective rain. Tornadoes seem likely as well, given 300-500 m2/s2 of 0-3 km SREH over the NW Turkey region. The threat shifts southward during the night as the cold front accelerates in the GFS model.