Convective Outlook: Sun 05 Jun 2022

LOW SLGT MDT HIGH SVR

What do these risk levels mean?

Convective Outlook

VALID 06:00 UTC Sun 05 Jun 2022 - 05:59 UTC Mon 06 Jun 2022

ISSUED 07:05 UTC Sun 05 Jun 2022

ISSUED BY: Dan

A very messy pattern is expected on Sunday as pulses of rain spread northwards across Ireland, England and Wales, particularly heavy from Wales across the Midlands to East Anglia, and increasingly into northern England. This may contain some lightning initially across portions of East Anglia, but likely weakening with time as profiles become fairly saturated. Extensive cloud, and even some fog, is likely to be left in its wake across southern and central Britain. Forecast profiles reveal a cap at 850hPa that will require surface temperatures near 20C to initiate surface-based convection across SE England, but the cap is much weaker towards SW England.  If sufficient surface heating can occur then there would be scope for heavy showers and thunderstorms to develop along a marked west-east convergence zone in southern England given the slack low-level winds, and this risk does persist well into the evening hours. The setup is also complicated somewhat by forced ascent along the rear side of the Theta-E plume as PVA associated with an upper low sliding into the western English Channel engages. This aspect is also uncertain, but could provide the focus for deep convection that persists well into the evening or perhaps overnight period as the focus shifts from SW England initially ENE-wards into the south Midlands and SE England/East Anglia late in the day. This could drive areas of heavy, showery rain bringing the risk of locally high rainfall accumulations and some surface water flooding. Lightning may not be overly-active with this feature, but heavy downpours are certainly a possibility. A conditional/marginal SLGT has been introduced, but will be dependent on sufficient cloud breaks/surface heating and it is certainly plausible very little lightning occurs. A SVR was issued for the risk of local surface water flooding. The moist boundary layer and vorticity stretching along convergence zones would promote the chance of a couple of funnel clouds.