Storm Forecast
Valid: Thu 01 Dec 2016 06:00 to Fri 02 Dec 2016 06:00 UTC
Issued: Wed 30 Nov 2016 23:24
Forecaster: GATZEN

A level 1 was issued for southern Spain and Portugal as well as for northern Morocco mainly for tornadoes.

SYNOPSIS / DISCUSSION

A deep polar trough extends across eastern Europe into the east Mediterranean as far south as Egypt. Cool and dry air masses have spread into south-eastern Europe, but some moister air has remained in the wake of Turkish plateau over the Mediterranean Sea, where it overlaps with steep lapse rates. QG lift is expected due to a passing short-wave trough rotating around the southern periphery of the east European low geopotential. Vertical wind shear weakens over the forecast domain and severe weather threat decreases from the west. So no threat level is issued. However, east of the forecast domain, stronger vertical wind shear can support organized storms, capable of producing excessive rain and tornadoes.

Western Europe is dominated by a mid-level ridge and weak lapse rates. Over south-western Europe, a weak trough approaches from the west. Ahead of this trough, a moist and unstable air mass is advected into Portugal and southern Spain. Rich moisture will likely stay close to the coasts as dry air over the peninsula is not expected to be pushed away. Given some QG forcing and low-level convergence, convective activity spreading into the area will likely go on for most of the period although weakening due to dry air advection at low levels. Main potential for some organized storms exist over the southern parts and into northern Morocco, where strong vertical wind shear is expected especially at low levels. Tornadoes are expected to be the main threat, and a level 1 is issued. Late in the period, severe potential is forecast to decrease in response to low-level stabilization.