Storm Forecast
Valid: Sat 02 Jan 2010 08:00 to Sun 03 Jan 2010 06:00 UTC
Issued: Sat 02 Jan 2010 08:36
Forecaster: KOROSEC
A level 1 was issued for much of Greece, Aegean sea and western Turkey mainly for excessive rainfall, tornadoes and severe wind gusts.
A level 1 was issued for northwestern Iberian Peninsula mainly for excessive rainfall, severe gusts and tornadoes.
SYNOPSIS
A large scale trough over eastern half of Europe shifts east while another trough with a well-defined frontal system approaches Iberian Peninsula. An impressive mid-level jet with its left-exit region over southeastern Europe will serve as a focus for the main deep convection area today.
DISCUSSION
... Greece towards western Turkey ...
An upper level divergence will result in widespread ascent ahead of the trough axis crossing the area during the daytime hours. Quite an impressive 30-40m/s deep layer shear will overlap with week to moderate instability. Numerous showers and thunderstorms will form and gain organization given the favorable dynamics. The main threat, especially over western Greece and western Turkey, should be convective excessive rainfall due to orographic precipitation combined with convection going onshore from the sea. Given the strong shear also at low levels, a few severe wind gusts and tornadoes are possible as well, especially along the coastal areas where LL instability and shear will be maximized.
Additionally, in weak low-level wind field over eastern Adriatic, a few waterspouts can form later in the afternoon along southern Croatian coast and sothwards, given the quite high LL lapse rates and several hundreds of CAPE in place.
... Portugal, NW Spain ...
Another disturbance approaches Iberian Peninsula in the second half of the forecast period. Models simulate that several hundreds of MLCAPE will be possible along the cold front, overlapping with moderately high shear at all levels. High SREH3 up to 400m^2/s^2 and above 20m/s LL shear suggest that rotating storms will be possible and therefore a tornado threat will exist. Another threat will be an excessive rainfall over extreme NW Spain as a result of strong SW-erly upslope flow combined with deep convection going onshore later on. Local flash floods will be possible overnight.
