Mesoscale Discussion
Valid: Tue 30 Jul 2024 19:00 to Tue 30 Jul 2024 23:00 UTC
Issued: Tue 30 Jul 2024 18:51
Forecaster: TUSCHY

This Mesoscale Discussion was issued to highlight current thunderstorm activity in the level 1 area.

As anticipated, CI is currently underway in the western fringe of the level 1, where surface temperatures peaked in the mid/upper thirties with dewpoints in the lower to locally mid twenties. This equals MUCAPE values in the 3000 to 4000 J/kg range (modified WRF-NMM soundings).

Latest satellite/radar loops indicate explosive CI next to Tours with deep hail cores (f.ex. 60 dBz reflectivity temporarily resides in 10-11 km AGL)! This is the time, where a few significant hail reports are forecast despite meager shear and poor hodographs.

Latest nowcast products take this pulsating cluster into the Paris area around midnight. CIN increases from now on but MUCAPE in the 2-3 kJ/kg range should persist into the Paris metro area.
Weak shear but abundant CAPE support pulsating activity with a temporal hail risk. In the meantime, excessive rain is likely with PWs around 45 mm and slow storm motion next to a few strong (wet) downbursts.

More/erratic CI is possible N and SE of the current activity with a lowered severe risk f.ex. for any storm activity near the coast where lower MUCAPE values persist. The main risk remains the rain threat and this activity is not covered with this MD polygon.