Storm Forecast
Valid: Wed 08 Apr 2020 06:00 to Thu 09 Apr 2020 06:00 UTC
Issued: Wed 08 Apr 2020 08:45
Forecaster: GATZEN

A level 1 was issued across south-eastern Turkey mainly for large hail and severe wind gusts.

A level 1 was issued across northern Iraq and surroundings mainly for large or very large hail and severe wind gusts.

A level 1 was issued across the Pyrenees mainly for large hail.

SYNOPSIS

A mid-level ridge remains across Central Europe. It is flanked by an intense polar jet stream across Scandinavia. A broad upper trough is located over the east Mediterranean. Another mid-level vorticity lobe stretches from western France to the west Mediterranean. Rich boundary layer moisture can be found across western France, from western Iberia to Morocco, and across the east Mediterranean. Lapse rates are weak over most places, except for the Pyrenees, Atlas mountains, and Turkey. Steep lapse rates across northern Europe do not overlap with sufficient boundary layer moisture.

DISCUSSION

Pyrenees

Convective storms are expected to develop close to the center of the mid-level trough today. Cold mid-level air masses and diurnal heating will result in steep lapse rates that overlap with rather high moisture today. Superimposed to topographic circulations and associated lift, convection initiation is forecast in the afternoon. Vertical wind shear is weak, and organized storms are not expected. However, some marginal large hail is forecast given the very low wet bulb freezing level.

North-eastern Spain

Close to the mid-level trough situated across north-eastern Spain, latest satellite imaginary indicates sheets to clouds that will limit diurnal heating today. However, in areas with sufficient heating, some weak uncapped surface-based CAPE is expected to develop. Initiation is questionable due to marginal instability, weak lift, and quite strong vertical wind shear. However, a few storms are not ruled out, especially over the higher terrain. Storms that form will organize given strong vertical wind shear in excess of 15 m/s. This can result in some multicells capable of producing locally large hail. Threat is to marginal for a risk area, though.

Southern Turkey

Within the base of the east Mediterranean trough, showers and thunderstorms are forecast today. Best potential is expected across south-eastern Turkey due to rich boundary layer moisture and steeper lapse rates, but weak CAPE is also expected farther west. Severe potential will be also higher in the eastern portions where straight-line hodographs and deep-layer vertical wind shear up to 15 m/s support multicells. Furthermore, a deep boundary-layer indicates an increased potential of severe wind gusts, and the low wet-bulb freezing level increases the threat of locally large hail. Potential of severe will be rather limited, though, given weak CAPE and lift. Storms are expected to decay after sunset.

Iraq

At the eastern flank of the east Mediterranean trough, a jet streak will progress north-eastwards with its cyclonically-sheared exit affecting parts of Iraq. A frontal boundary is present across the region with some warm air advection from the east towards Syria. Forecast soundings indicate CAPE up to 500 J/kg and a deep boundary-layer in the afternoon. Additionally, long straight-line hodographs are forecast, with deep-layer shear in excess of 20 m/s.

During the afternoon, well-organized storms are expected to form, including mirror-splitting supercells. Main threat will be large or very large hail, together with severe wind gusts. Storms are expected to weaken in the evening due to rapid boundary-layer stabilization.