Convective Outlook: Sat 11 Apr 2020
LOW
SLGT
MDT
HIGH
SVR
What do these risk levels mean?
Convective Outlook

VALID 06:00 UTC Sat 11 Apr 2020 - 05:59 UTC Sun 12 Apr 2020

ISSUED 07:11 UTC Sat 11 Apr 2020

ISSUED BY: Dan

Some early elevated convection may be occur near NE / E Scotland and NE England first thing on Saturday morning, but this should soon clear to the North Sea. Otherwise, attention turns to a subtle shortwave slowly drifting ESE-wards across the British Isles on Saturday, while skies across much of central and southern Britain should be relatively clear given a dry airmass with depth (aside from some thin cirrus). This should allow fairly unimpeded surface heating of the relatively warm, moist low-level airmass to occur (dewpoints 11-14C), yielding 400-800 J/kg CAPE. Sea breezes will develop, leading to zones of confluence and convergence inland (most pronounced from Devon across to London). Given the slack surface pattern, other low-level convergence boundaries are also likely, such as close to the English/Welsh border. 


Convection will likely occur during the afternoon hours where low-level convergence is maximised, although this may struggle to sustain itself given weak shear and a rather dry atmosphere. However, eventually a few isolated heavy showers or thunderstorms may form, more especially towards late afternoon and into the evening hours, capable of producing some sporadic lightning, hail up to 1.5cm in diameter and (given inverted-V profiles) wind gusts 30-35mph. Exact location of where lightning will occur is rather uncertain, but we have attempted to highlight areas considered most likely with a low-end SLGT - but this is rather dependent on how sustained any convection can become.
Surface troughing is expected to develop by the evening, and this combined with weak forcing aloft may allow showers and the odd thunderstorm to persist will into the night as they drift across the Midlands and East Anglia.