Convective Outlook: Sun 29 May 2022
LOW
SLGT
MDT
HIGH
SVR
What do these risk levels mean?
Convective Outlook

VALID 06:00 UTC Sun 29 May 2022 - 05:59 UTC Mon 30 May 2022

ISSUED 06:08 UTC Sun 29 May 2022

ISSUED BY: Dan

An upper low over Norway will eventually eject and drift southwestwards towards Scotland on Sunday night. In advance of this, an upper trough will migrate southwards across England and Wales during Sunday daytime, aiding to deepen the convective layer. Diurnal heating is likely to yield a few hundred J/kg CAPE, most pronounced across Wales and SW England where residual warm, moist air (850hPa Theta-W >8C) is present. Scattered showers are anticipated to develop across many parts of England and Wales in particular (a few also in Scotland and eastern Ireland). Forecast profiles reveal the depth of convection will, for the most part, be restricted to below ~13,000ft and therefore the risk of lightning is very low in any one location. However, there could be a few isolated strikes if any cells can punch higher, this deemed most likely in south Wales and/or SW England where low-level convergence and orographic forcing is maximised (in conjunction with higher instability). Speed shear through the cloud layer is fairly weak, and so pulse-type storms are most likely, and given their restricted depth it is plausible convection may spread out and morph into areas of showery rain. Slow shower motion could produce locally prolonged downpours, with scope for 20-30mm in a few isolated locations (again this most likely in Wales/SW England). The generally slack surface pattern could be favourable for a few funnel clouds. Showers will gradually fade during the evening hours as nocturnal cooling of the boundary layer commences, and the aforementioned upper trough exits to the south.