Intense rainfall in the Alps of NW Italy, SE France and S Switzerland – August 8, 2017

Intense rainfall is expected over the western Alps in northwestern Italy, southeastern France and southern Switzerland today. Rainfall totals will locally exceed 100 mm / 24h. There will be a significant risk for locally intense flash flooding.

A very strong mid-level southwesterly jetstream is present ahead of the advancing trough, currently located over France. Strong upslope flow, orographic lift and synoptic scale lift over the left exit region of the jetstreak will provide a favourable environment for formation of training cells.

Various high-resolution models indicate widespread totals of 40-100 mm / 24h, while locally totals may exceed 150 mm / 24 h. Expect enhanced threat of (locally intense) flash flooding.

In addition, these thunderstorms will also pose a threat for hail (locally large accumulations can build up) and severe wind gusts. Follow these storms on radar!