Mesoscale Discussion
Valid: Tue 23 Jun 2026 13:00 to Tue 23 Jun 2026 16:00 UTC
Issued: Tue 23 Jun 2026 13:27
Forecaster: TUSCHY

This Mesoscale Discussion was issued to highlight an evolving severe risk over NW France with an essential level issuance.

A convectively enhanced positive PV anomaly crossed the Bay of Biscay N/NE and entered the English Channel from the W. GFS captured this disturbance since yesterday noon with IFS constantly being displaced to the NW (now approaching the EZ solution). EPS data remains rather reluctant with CI but increased signals a bit over NW France.

This feature should add some BL response with lowering MSLP, increasing onshore flow during the afternoon/evening hours along its western fringes.

This modified sea breeze will push well inland with maximized BL moisture along its leading edge, pushing MUCAPE into the 1500 J/kg range and probably breaking the cap on an isolated to scattered scale. Shear is weak, but a deep mixed BL with DCAPE well in excess of 1000 J/kg points to healthy and probabaly severe downdrafts next to some hail. A few gusts up to hurricane force are forecast and even a temporal cold pool driven MCS event could spread far SE.

Along a sharpening N/S aligned dry line over far W France, further CI is now possible with intersecting outflow boundaries from the N. Severe gusts and hail will be the main issue.

CI will be in the 15-16Z range.

This forecast change needs an upgrade and the MD equals a level 1.