Storm Forecast
Valid: Tue 12 Jan 2010 06:00 to Wed 13 Jan 2010 06:00 UTC
Issued: Mon 11 Jan 2010 23:40
Forecaster: KOROSEC

SYNOPSIS

While much of continental Europe stays cool and stable, a new deep trough with attendant cold front enters SW-ern Europe. Furthermore, a secondary low forms over western Mediterranean sea early Wednesday morning. Another short-wave trough affects SE-ern Mediterranean sea while moving east.

DISCUSSION

... Bay of Biscay, southern Spain and Portugal ...

During the day, deep trough over central Atlantic moves east and surface depression intensifies west of UK. Ahead of this system/cold front, warm air advection is pushed towards UK and across southern Iberian Peninsula. Models agree that marginal instability will release with steepening mid-level lapse rates behind the front, mostly over Bay of Biscay. There, numerous showers and thundestorms will form within maritime airmass. But only weak wind field preclude any organized cells.

More to the south across Iberian Peninsula, quite impressive shear will become avaiable within the strong mid-level jet streak (30-45m/s). Both LL shear/SREH will also be very high (25-30m/s, 400-500m^2/s^2) given the favorable wind profiles in the lowest levels. However, almost no instability can be found on the models, except a minor signals over SW Spain, so organized convection in unlikely. The rapidly moving cold front will mostly bring high precipitation sums and some flooding locally, as the highest amounts will be mostly from orographic rainfall and no deep convection is forecast. Therefore no threat levels has been issued.

During the second half of the night, a trough/front digs into western Mediterranean and a new surface low will form. There, some deep convection is possible as models simulate marginal instability along the attendant cold front. With moderately high shear in place, some organized storms can take place. But still, it is too marginal for any threat levels there.

... Aegean Sea and western Turkey ...

While short-wave trough moves east across SE-ern Mediterranean, some convective storms will form along the surface front. Given the weak wind profiles and low 600-1000m AGL LCL heights, a few waterspouts will be possible where LL instability will be maximized. But chances for more organized storms are very low.