Extended Forecast
Valid: Sun 12 May 2024 06:00 to Mon 13 May 2024 06:00 UTC
Issued: Fri 10 May 2024 14:40
Forecaster: TUSCHY

A level 1 was issued for E-Turkey into Armenia mainly for large hail, severe wind gusts and heavy rain.

A level 1 was issued for parts of far S-France mainly for isolated large hail and severe wind gusts.

SYNOPSIS

Ongoing blocking ridge over CNTRL into N-CNTRL Europe gets framed by extensives waves, which extent into the Bay of Biscay to the W and into the E-Mediterranean to the E of the ridge.

Along the surface a structuring and extensive low pressure channel over France into Switzerland becomes the main focus for most widespread thunderstorm activity.


DISCUSSION

... E-Turkey into Armenia ...

Ongoing overlap of modest MUCAPE with strong DLS next to the subtropical jet assist in another round of early/scattered CI with interfering convection. Any more discrete storm poses a large hail and severe wind gusts risk next to heavy rain.

... Hautes-Pyrenees to W-Aude (S-France) ...

During the afternoon, modest BL moisture beneath 35-40 kt westerly flow support a short window of opportunity for a few organized multicells/isolated supercells in an 400-800 J/kg MUCAPE and 15 m/s DLS environment. Somewhat enlarged low to mid-level hodographs indicate a chance for at least temporal updraft rotation. Large hail and strong to isolated severe wind gusts will be the main risk.

... France into UK ...

An extensive surface pressure channel, filled with an unstable and moist airmass will be the focus for scattered to widespread CI. For France, very weak shear at all levels assists in numerous growing but rather disorganized clusters. Initiating cells, which take profit of weakly capped 500-1000 J/kg MUCAPE will pose a temporal hail and wind gust threat, but heavy rain becomes the main issue betimes. Current idea is that parts of NE France could see a rainfall-driven upgrade due to better forcing.
During the overnight hours, this risk also translates to Switzerland/far N-Italy with heavy rain the main risk.

DLS increases somewhat towards UK so a bit more progressive clusters lower the overall convective rainfall risk. Repeated thunderstorms could bring heavy rain on a local scale. Isolated hail and a few funnel reports (rich LL CAPE) accompany thunderstorms. This activity weakens after sunset.