VALID 06:00 UTC Tue 31 May 2022 - 05:59 UTC Wed 01 Jun 2022

ISSUED 06:38 UTC Tue 31 May 2022

ISSUED BY: Dan

A broad upper trough covers the British Isles on Tuesday, its orientation changing from NNW-SSE at 06z to become almost W-E by 06z Wednesday. Cooler air in the mid-levels will advect further south than on Monday, and the net result is a deeper convective layer yielding 400-700 J/kg CAPE in response to modest surface heating and cloud tops potentially around 20,000-25,000ft. While CAPE is higher than Monday, and encompasses more of the mixed phase region, it is also stretched over a much deeper layer. Areas of showery rain will already be present in the morning, these turning more convective through the day with numerous other showers developing with time. By the afternoon showers will become widespread with a few thunderstorms likely too, although fewer showers across much of southern Ireland, south Wales and SW England as profiles here become increasingly subsided. The greatest risk of lightning, which is likely to be more widespread than the past couple of days, will be associated with the belt of steep mid-level lapse rates from western Scotland southeastwards to SE England - as broadly depicted by the SLGT issued. However, shear will be fairly weak in this region within the upper trough axis, and the tall skinny CAPE profiles will likely lead to slow-moving heavy showers with locally high rainfall totals, but perhaps limited lightning/morphing into areas of showery rain.