Storm Forecast
Valid: Tue 10 Jan 2017 06:00 to Wed 11 Jan 2017 06:00 UTC
Issued: Tue 10 Jan 2017 00:28
Forecaster: DAFIS

A level 1 was issued for SE Greece and SW Turkey mainly for excessive precipitation and tornadoes.

A level 1 was issued for N UK and SW Norway mainly for severe convective wind gusts.

A level 1 was issued for W Greece mainly for excessive precipitation.

SYNOPSIS

The wide cold bubble over SE Europe will remain stationary the following 24 hours with an embedded short-wave trough crossing Greece and Turkey by the morning of Wednesday. From the West, a wide ridge is forming in North Atlantic, stretching to NE but also another short-wave trough will cross the level 1 area drawn over NW Europe during the night of Tuesday. At the surface, a cold front will enter France and a complex frontal activity will be present over North Sea. Pulsating storms are expected in West Mediterranean. Finally, at the early morning of Wednesday, a warm front will progressively move over the Ionian Sea towards Greece, where plenty of convection is forecast.

DISCUSSION

SE Greece and SW Turkey
By the early morning of Tuesday, a short-wave trough will cross the highlighted area, providing substantial lift to an already strong convergence zone near the surface. Even though the mid-level lapse rates are steep and PBL very moist, meager CAPE is forecast by NWP models. Nevertheless, persistent clusters of storms may lead into flash floods in Dodecanese Islands and especially at the steep coasts of Turkey where orographic lifting will also provide extra ingredients to this unstable environment. Excessive precipitation and tornadic waterspouts will be the main threats.

.... N UK and SW Norway ....
During the night of Tuesday, a short-wave trough will cross N parts of North Sea, associated with a vigorous low pressure system east from Iceland. Several thunderstorms are expected to hit the coasts of N UK and Norway later on, and the main threat will be severe wind gusts as 850 hPa wind speeds will exceed 30 m/s. Convective and non-convective wind gusts are expected to reach 35-40 m/s during the night.

.... W Greece ....
As a low pressure system is expected to emerge at the Tyrrhenian Sea, its warm front will move towards Greece by the early morning of Wednesday. CAPE of about 400 J/kg will overlap with meager DLS (15-18 m/s) but sufficient to support one or two clusters of storms, able to produce excessive precipitation. A main threat will also be the transition of snowfall into rainfall over W Greece with a flash flood threat.