Storm Forecast
Valid: Tue 23 Feb 2010 06:00 to Wed 24 Feb 2010 06:00 UTC
Issued: Mon 22 Feb 2010 22:33
Forecaster: KOROSEC

A level 1 was issued for western and SW Iberian Peninsula and northern African coast mainly for severe wind gusts, large hail and tornadoes.

SYNOPSIS

A progressive weather pattern continues mostly over southern Europe, while the rest of Europe stays stable. At surface, weak surface fronts will be the focus for convective activity. The first over southern Adriatic and Aegean sea and the second over Iberian Peninsula. Overnight to Wednesday, deep surface low SW of UK slowly approaches western Europe and will be affecting France on Wednesday.

DISCUSSION

... Iberian Peninsula, southern Mediterranean...

An impressive subtropical jet lies over the southern Iberian Peninsula and Mediterranean sea. Numerous disturbances can be found within this westerly zonal flow where the main activity will be found over Iberian Peninsula towards the northern African coast. Strong forcing/lifting will lead into numerous showers and thunderstorms along with lots of stratiform rainfall. Additionally, strong shear at all levels seem enough supportive for organized storms. Therefore, tornado and large hail threat as well as severe wind gusts will be possible with the strongest cells. A level 1 threat areas has been placed where the possibilities are higher.
Another threat is the flooding risk due to persisting upslope flow onto Iberian Peninsula which received a lot of precipitation already in the previous days. Though, excessive convective rainfall is quite limited with only marginal instability in place, but models do agree in additional extensive rainfalls especially over western Iberian Peninsula.

... western Turkey and southern Adriatic sea...

Weak short-wave trough/disturbance crosses southern Adriatic during the late morning hours and enough forcing will lead into some convective activity where instability is maximized. Good LL shear/SREH will support some storm organization which will enhance rainfall threat over the eastern Adriatic coastal areas. There, persisting WSW-erly upslope flow will be already pushing moisture inland. Locally, long lasting rainfalls could lead into flash floods.

Further east, models are consistently showing marginal instability near the frontal zone crossing Aegean sea towards western Turkey during the second half of the forecast period. Moderate shear and helicity suggest that some organized storms will be possible. Isolated multicells and rotating storms can form, posing a threat for an isolated tornado or strong wind gusts. However, limited coverage prevents issueing of any threat levels attm.