Mesoscale Discussion
Valid: Sat 24 May 2025 13:00 to Sat 24 May 2025 16:00 UTC
Issued: Sat 24 May 2025 12:55
Forecaster: TUSCHY

This Mesoscale Discussion was issued to update the severe risk over parts of Ireland. Please keep in mind that the mentioned severe risk lasts beyond the MD's validity well into the overnight hours.

Latest remote sensing data indicates a robust dry slot approaching the MD area from the W, as a cold front rushes E/NE. The main focus for isolated DMC activity arises along the cold front but also in the postfrontal area, which resides ahead of an approaching back-bent occlusion and an attendant sharp surface trough. As the dry slot overspreads the highlighted area, some low-end to modest MUCAPE build-up is forecast. Latest 2m temperature and dewpoint readings reside aoa 15C and are in line with NWP guidance.

MUCAPE will be in the 200-500 J/kg range with DLS approaching 20 m/s. Hodographs show rather complex signatures, common for split-type fronts with elevated CAA overspreading near surface WAA. Hence it remains unclear how deep updrafts can grow before a more destructive veer-back interference occurs (as backing resides in a deep part of the CAPE area). Latest NWP guidance indicates at least isolated thunderstorm probabilities. This combined with very low LCLs point to a risk of a few shallow mesocyclones with a low-end tornado threat next to small hail/graupel and gusts (although even non-electrified convection will be accompanied by that risk). In addition some models bring LLCAPE in the 200 J/kg range with a slow decreasing trend beyond sunset. The risk extends well into the first part of the overnight hours.