Tomorrow we have issued a Marginal chance for severe weather for parts of North/Central Spain, France and North Italy. We will update tomorrow if we feel a slight should be issued as there is some uncertainty in charts as to where the storms will develop.
Tomorrow afternoon 2 upper troughs dominate, one situated over North Italy the other Central France. The main risks are excessive precipitation, gust front formations including severe winds and moderate to large hail.
Lets start off with France and Spain, the main threat for France will be mid-afternoon and on wards as SBCAPE over the center range from 2,000-4,000 j/kg with dew points at 21-24°C, the AROME and GFS models agree with potent updraft potentials in these regions which brings a risk of moderate to large hail with the chance of accumulations forming.
Excessive precipitation is a risk with these cells with PWAT charts showing around 1.5″. There is SBCAPE values of 4,000 j/kg around the Pyrenees but with a moderate CAP in place it looks it wont possibly be broken until the evening. The threat of severe weather with the central systems will push further east with risks of Localized flooding as it progresses.
Deep layer shear is around in these regions so a possible supercell can not be ruled out if the updrafts sustain. Spain will hold off until the late afternoon/evening as there is a strong CAP inversion in play during the day which the high temperatures and low dew points will keep at bay. High lightning totals are a threat tomorrow with these systems so keep an eye on the sky and beware of the possible hazards.
North Italy is under a Marginal for the chance of severe thunderstorms firing off in the afternoon with a possible dry line formation. SBCAPE values are more extreme to the North West/North with values ranging from 1,000-3,000 j/kg.
One city to outline with the severe weather threat is Milan as AROME models are showing thunderstorms firing off to the North of the city and moving South/South East, these cells do have the potential for moderate to high lightning totals, heavy rainfall, straight line winds and hail. Deep layer sheer is present within the area at 40kts so a mesocyclone forming cant be ruled out on some of these thunderstorms.