Storm Forecast Valid: Sat 30 Aug 2014 06:00 to Sun 31 Aug 2014 06:00 UTC Issued: Sat 30 Aug 2014 02:46 Forecaster: TUSCHY
A level 1 was issued for S-Norway and the Kattegat mainly for excessive rain and an isolated tornado event.
A level 1 was issued for E-CNTRL Spain mainly for an isolated large hail event.
A level 1 was issued for NW Italy mainly for isolated large hail.
Ex-hurricane's (CRISTOBAL) WAA induces rapid mid-layer thickness increase west of Ireland (e.g. 500 hPa height increase in excess of 10 gpdm/12h). This causes a sharpening thermal gradient over Ireland and UK between the ridge and a stationary vortex over N-Scotland. Both, the northward building ridge and intensifying mid/upper jet winds along the SW fringe of that vortex cause the vortex's slow SE-ward motion during the overnight hours ... approaching Benelux from the NW during the end of the forecast. Advection of moist marine air ahead of that low result in marginal thunderstorm conditions for this forecast period.
Positive tilted trough over NE Europe features cold mid-levels, but no distinct moisture source is available to feed any storms. Hence scarce thunderstorm probabilities exist.
Numerous broad mid/upper waves, cool mid-levels and decreasing mid-layer thickness affects S-Europe including the Mediterranean. As 700 hPa temperatures remain aoa 6°C, the air mass remains capped for most parts ... excluding mountainous regions.