VALID 06:00 UTC Sat 23 May 2020 - 05:59 UTC Sun 24 May 2020
ISSUED 21:14 UTC Fri 22 May 2020
ISSUED BY: Dan
Broad upper trough covers the British Isles on Saturday, with a pronounced shortwave swinging eastwards across Ireland, Wales and England during the morning hours, exiting to the North Sea by mid-afternoon. Behind this feature, upper ridging will build from the west, gradually suppressing deep convection.
Isolated to well-scattered showers are expected to spread eastwards across Ireland, Wales and England during the day, associated with the shortwave moving through but also aided by diurnal heating and some minor low-level convergence, despite the strong surface winds. The deepest convection is likely across East Anglia / SE England around lunchtime/early afternoon, but warming aloft through the afternoon will ultimately reduce the depth of convection with each passing hour. Nonetheless, given 300-500 J/kg CAPE, cloud tops to 500mb (18,000ft / ELTs as low as -30C) and 20-30kts shear through the cloud-bearing layer, a few sporadic lightning strikes may be possible. A low-end SLGT may be considered if confidence improves a little. Some hail and gusty winds will be possible from the strongest cells.