Storm Forecast
Valid: Thu 11 Feb 2016 06:00 to Fri 12 Feb 2016 06:00 UTC
Issued: Wed 10 Feb 2016 22:37
Forecaster: GATZEN

SYNOPSIS and DISCUSSION

A broad trough covers northern and central Europe. A strong mid-level jet vurves around its periphery. At lower levels, cold air masses have spread into the north Mediterranean. As a consequence, moisture is very limited over most of the continent. Better moisture across the southern Mediterranean and the Bay of Biscay do not overlap with steep low-level lapse rates within the trough further north.

Some thunderstorms are expected across the North Sea and the northern Adriatic Sea. Weak CAPE and weak vertical wind shear are present and severe thunderstorms are not forecast.

Across the central Mediterranean, chances of thunderstorms are forecast as well. South of the main frontal boundary, better moisture is present with low-level mising ratios around 9 g/kg. Some 100s J/kg MLCAPE are expected by latest GFS model.

Storms that form may organize given around 10 m/s 0-3 km vertical wind shear. Multicells may produce severe wind gusts given 15 m/s background flow at 850 hPa. Additionally, excessive rain may be favoured along western Greece where upslope flow is present and training storms may continue for some time.

Some more storms may form late in the period as another vort-max reaches the forecast area, associated with a frontal system at low levels. An upper-level front will cross the Bay of Biscay in the evening hours, and increasing low-level lapse rates evolve in the response of low-level stretching. Low-level moisture is expected to increase from the south-west later on. Some CAPE can evolve especially across the western Bay of Biscay, where lapse rates and moisture may overlap. Further south-west, however, mid-level sinking is expected at the warm flank of the upper-level front, and storms become increasingly unlikely.

With strong low-level vertical wind shear, some intense storms may evolve during the night and Friday morning, likely lineary organized with a threat of severe wind gusts. A level 1 is issued.