Storm Forecast
Valid: Thu 13 Dec 2018 06:00 to Fri 14 Dec 2018 06:00 UTC
Issued: Thu 13 Dec 2018 05:59
Forecaster: GATZEN

SYNOPSIS

A high is located across northern Europe, flanked by an east-European trough that extends into Central Europe. Another trough cuts off over the Iberian Peninsula and spreads to Algeria during the period. At lower levels, dry air masses dominate Europe. A zone of better moisture extends from west to east across the central parts of the Mediterranean and it pushed northwards where is affects Italy, Greece, and Turkey. With weak lapse rates, only marginal instability is expected. Slightly higher MLCAPE is forecast over the Bay of Biscay and later over the west Mediterranean near the base of the cut-off trough due to better lapse rates.

DISCUSSION

Bay of Biscay, Iberian Peninsula, west Mediterranean including Balearic Islands

Thunderstorms are forecast close to the center of the cut-off low. These storms will have limited potential to organize given weak 0-3 km vertical wind shear. However, deep layer shear is strong over the Bay of Biscay and parts of Iberia what could support some better organized storms. The Best potential is expected over western Iberia, where latest models support a line of storms moving south in the morning and noon hours. Main threat will be severe wind gusts, although the potential is very limited. Additionally, marginally severe hail and excessive precipitation are not ruled out. The potential for severe weather is expected to be too low to issue a level 1 at this time.

Central and east Mediterranean including western and southern Italy, western Greece, and southern Turkey

With weak CAPE and weak vertical wind shear, thunderstorms are forecast to be weakly organized. However, slow moving storms may produce locally excessive precipitation as precipitable water is not too low at about 25 mm. The potential is limited and a threat level is not issued.