Convective Outlook: Fri 26 Nov 2021
What do these risk levels mean?
Convective Outlook

VALID 06:00 UTC Fri 26 Nov 2021 - 05:59 UTC Sat 27 Nov 2021

ISSUED 09:23 UTC Fri 26 Nov 2021


A very messy period for ascertaining site-specific detail, as a marked mid-level low slides southwards down the North Sea/eastern Britain on Friday and Friday night, the associated significant cold pool creating steep mid-level lapse rates and a broadly unstable environment in response to relatively warm SSTs. Coastal showers and more widepsread areas of showery rain will spread erratically southwards through this forecast period, and while the overall risk of lightning is rather low in any one location a few isolated lightning strikes could occur just about anywhere. 

Perhaps particular attention is given close to the wrap-around occlusion that affects the Moray Firth and NE Scotland during the daytime, and then shifts into SE Scotland / Cen N and NE England during the evening and night hours. Here, especially later in the day, strong ascent, substantial wind shear in the vicinity of the frontal boundary and weak/limited CAPE largely confined to the mixed-phase region may be sufficient to produce a few sporadic lightning strikes. Very strong gradient winds are expected in NE / E / SE Scotland and NE England, but potentially exacerbated by strong convection in the area with some NWP guidance suggestive of gusts near 100mph offshore.  An additional focus for a few lightning strikes may also be west Wales down to SW England on Friday night, as showers develop along a convergence line.