Mesoscale Discussion
Valid: Tue 11 Jul 2023 15:00 to Tue 11 Jul 2023 18:00 UTC
Issued: Tue 11 Jul 2023 15:23
Forecaster: GROENEMEIJER/PUCIK

Temperatures have risen to around 35 C with dew points in the 16-20 C range, which implies very high latent instability is present with CAPE values of 2000 - 4000 J/kg. The environment is strongly sheared with as much as around 15, to locally 20 m/s of 0-3 km bulk shear. Storms are currently initiating in several locations, but most prominently and rapidly across the Rhone Valley and northeast to east of the Massif Central.

In line with the latest convection-allowing model runs it is anticipated that these storms will quickly develop into powerful supercells with a risk of very large hail > 5 cm. In addition, the environment is highly favorable for severe and, possibly, extreme wind gusts above 32 m/s, as it features a 2 - 2.5 km deep hot boundary layer. As a result, a fairly rapid merging of strong cold pools is expected, and one or more forward propagating and intensifying bow echoes are expected within the indicated area.