Storm Forecast
Valid: Sat 13 Jun 2015 06:00 to Sun 14 Jun 2015 06:00 UTC
Issued: Fri 12 Jun 2015 23:16
Forecaster: DAFIS

A level 2 was issued for Belarus mainly for excessive rain, large hail, severe wind gusts and isolated tornado events.

A level 1 was issued for most of Germany, Czech Republic and west parts of Poland for excessive rain, large hail and severe wind gusts.

A level 1 was issued for parts of NE Spain, C-S France and west Alpine region mainly for excessive rain.


SYNOPSIS

The low pressure system NW of Spain and Portugal stays quasi stationary during this forecast outlook and small disturbances affect the nothern parts of Iberian pensisula. Strong, southerly, low level flow from Mediterranean is producing high values of MLCAPE in southern France and SW Alps where orography enchances the convection initiation.

Furthermore, a cold front is about to cross Germany with NE direction and will result to numerous storms along the country, some of them might become severe. Moreover, an upper air short wave trough is moving fast from Poland to Belarus and dissipates during the late afternoon having first cause severe storms in the area while high LL moisture and local convergence zones overlap with high values of MLCAPE.

Southern Europe is under a ridge pattern that cause the advection of very warm air masses from North Africa, although some storms may form during the late evening in Italy and Balkans with isolated hail events.


DISCUSSION

....Belarus....

The shortwave trough that abetted the formation of stong storms in Poland, is now moving eastwards to Belarus and during the evening severe thunderstorms are forecast. Strong DLS of more than 20m/s, low LCLs (<800m), SREH 0-1km in excess of 300m^2/s^2, LLS of 10-15m/s and >2000J/kg MLCAPE indicate a favorable enviroment for tornado occurence and large hail events. Referring to rich in moisture BL and steep lapse rates in the afternoun, excessive rain is expected by numerous well organised storm cells.

....Germany, Czech Reb. and Poland....

During the early morning of Saturday, a cold front is about to cross Germany, with NE direction, where it finds a very moist and warm BL (mixing ratios >10g/kg and Td>17C). Although MLCAPE of 2000J/kg is not overlapping with high DLS (max 15m/s), LLS shear values of 10m/s in NE Germany are forecast along with SREH 0-3km of 200-300 m^2/s^2 capable of producing long lived multicells, even supercells in NE parts during the afternoon with excessive rain and large hail to be the main threats.

....S France, NE Spain, W Alps...

Deep moist convection is forecast for this area once again. The southerly flow continues advecting warm and unstable air masses from Mediterranean, producing large values of MLCAPE which overlaps with decent DLS of 20m/s able to produce supercells. Furthermore, a LL convergence zone in NE Pyrenees and another one north of Corsica will result to excessive precipitation events during the late afternoon - early night, where SREH 0-3km is forecast to reach 300m^2/s^2 and waterspouts near the coasts should not be ruled out.