25-07-2019 07:21 | Estofex | m.b.t. 25-07-2019 t/m 26-07-2019
Storm Forecast
Valid: Thu 25 Jul 2019 07:00 to Fri 26 Jul 2019 06:00 UTC
Issued: Thu 25 Jul 2019 07:21
Forecaster: GATZEN
A level 2 was issued for N Wales, N England, and S Scotland mainly for large of very large hail, severe wind gusts and tornadoes and to a lesser extent excessive precipitation.
A level 1 was issued for N Spain, W France, and the British Isles mainly for large hail, severe wind gusts, and to a lesser extend tornadoes (N England and Scotland).
A level 2 was issued for the Alps and N Italy mainly for large hail and excessive precipation and to a lesser extent severe wind gusts.
A level 1 was issued for Belarus, W Russia, E Ukraine, Moldova mainly for large hail, severe wind gusts, and locally excessive precipitation.
SYNOPSIS
An amplified ridge flanked by a deep trough across the north-east Atlantic and a cut-off over east Europe is associated with a plume of extremely warm air originating from the Atlas mountains that spreads across western Europe. Warm air advection is maximized over parts of the British Isles and the North Sea. A cold front moves east over Spain, western France and western British Isles. Within the ridge, CAPE is maximized south of the Alps. Ahead of the cut-off across eastern Europe, a frontal boundary affects southern Russia.
DISCUSSION
British Isles
Warm air advection is expected east of a cold front that enters the British Isles from the west. A plume of extremely warm and well-mixed air spreads into England today, and low-level moisture is forecast to increase in the noon and afternoon below a capping inversion. Given strong diurnal heating, MLCAPE will exceed 2000 J/kg locally. Convection initiation becomes most likely in the afternoon across northern England and Scotland.
Storms that form will quickly organize given strong deep layer shear and favourably curved hodographs. Supercells are forecast capable of large or very large hail (> 5 cm). Additionally, severe wind gusts are forecast and excessive precipitation is locally not ruled out. Tornadoes are possible with any supercell that forms although LCLs are not particularly low. However, low-level hodographs will become longer in the evening due to the increasing low-level jet, with more than 100 J/kg 0-1 km SRH. Therefore, strong tornadoes are not ruled out. Late in the period, boundary layer cooling will decrease the threat of tornadoes and severe wind gusts. However, elevated storms will still be capable of large hail until the morning.
Across Wales and England, more storms are forecast ahead of the approaching cold front. Although boundary layer capping will be larger compared to the northern British Isles, strong vertical wind shear may support some supercells as well, capable of large hail. Clustering of these storms may result in some eastward propagation later on with chances of large hail in parts of England later on.
(alleen de voor onze streken relevante tekst overgenomen, klik hier voor de volledige forecast, red.)
Verwachtingen/waarschuwingen
