Mesoscale Discussion
Valid: Sat 03 May 2025 10:00 to Sat 03 May 2025 13:00 UTC
Issued: Sat 03 May 2025 09:52
Forecaster: TUSCHY

This Mesoscale Discussion was issued to higlight a more focused severe risk during the afternoon into the evening. Please keep in mind that the validity of this MD does not match the actual severe risk.

As the structuring surface wave awaits the approaching upper trough (see discussion in SWODY1), a confined corridor of enhanced severe evolves during the afternoon into the early evening hours in the MD area.

A small warm sector with backed LL winds and modest MUCAPE develops in the MD area. Forecast hodographs show enhanced backing of the flow above 4-5 km AGL, which vents the precipitation to the N/NW (away from E/SE-ward moving updrafts). Hence, longer lived updrafts are possible. Best veering resides in a 1-4 km layer AGL, where shear increases to aoa 15 m/s. In addition 0-3 km CAPE improves, although BL mixing could still remain an issue on a local scale.

A few supercells are forecast, which tend to grow into bowing segments. This would increase the severe wind gust risk with EPS data also indicating a low chance for Bft 10 gusts next to the heavily populated area of the Rhine Main area. Hail is possible on a local scale but rather deep backing (atop veering) in parts of the graupel area should lower the general risk.

Thereafter (during the evening hours), storms exit the MD E/SE and increasing CIN could lower the overall gust threat, but nowcast trends have to be monitored closely.

We nudged the MD a bit N to account for temporal training of initiating storms with heavy rain.