Convective Outlook: Sun 07 May 2023

LOW SLGT MDT HIGH SVR

What do these risk levels mean?

Convective Outlook

VALID 06:00 UTC Sun 07 May 2023 - 05:59 UTC Mon 08 May 2023

ISSUED 07:25 UTC Sun 07 May 2023

ISSUED BY: Dan

A reasonably high Theta-W airmass (>12C at 850hPa), having been drawn northwards through Saturday evening and night, will reside across East Anglia and SE England on Sunday. Convective overturning should gradually erode initially extensive low cloud, mist and drizzle through the morning, with increasing insolation and heating of this very moist low-level airmass (Td 13-15C), with Tmax expected to peak at 19-22C in places. Aloft, a longwave upper trough and associated cold pool will linger close to eastern Britain (and over western Europe), albeit gradually filling/warming through the day. Nonetheless, the thermodynamic profile, for a time at least, may be supportive of substantial CAPE (perhaps exceeding 1,000 J/kg SBCAPE) in response to diurnal heating. The situation is very finely balanced - if convection can develop reasonably quickly then there would be scope for deep convective cloud and the potential for some rather active thunderstorms for a time over East Anglia and perhaps SE England, however quicker clearance of the upper trough and/or slower development of convection will reduce this threat. Nonetheless, even with increasing mid-level capping through the afternoon forecast profiles are still supportive for a few heavy showers in eastern England, aided by sea breeze convergence - but the lightning risk would be markedly reduced. Elsewhere, a few heavy showers/weak thunderstorms may also develop in NW Scotland and the Central Belt during the afternoon/early evening.