Convective Outlook: Thu 28 Oct 2021

LOW SLGT MDT HIGH SVR

What do these risk levels mean?

Convective Outlook

VALID 06:00 UTC Thu 28 Oct 2021 - 05:59 UTC Fri 29 Oct 2021

ISSUED 06:20 UTC Thu 28 Oct 2021

ISSUED BY: Dan

Behind the waving cold front bringing very significant rainfall totals to NW England and S Scotland, scattered showers will affect portions of Ireland and western Scotland which may produce the odd isolated lightning strike - although the shallow nature of convection will generally restrict this potential. During the evening and night hours, a more pronounced shortwave will lift northeastwards in the broad southwesterly flow aloft, and the associated PVA will encourage areas of showery rain near a deepening low centre over Ireland / Irish Sea / Wales / SW England - the exact forecast evolution is a little uncertain, but some pockets of stronger convection may be possible capable of producing a few lightning strikes. Furthermore, depending on the phasing of various key ingredients there may be scope for some strong/damaging SLW near the surface low associated with deep convection wrapping around the western and southern flank, in a situation very similar to that experienced in Cornwall on 20 October 2021. Model guidance varies considerably as to where (or even if) this evolves, the general Irish Sea between Ireland and Wales (and adjacent land areas of SE Ireland and NW Wales) is perhaps most favoured at present, with ECMWF-based models tending to favour the Irish Sea while UKV leans towards Cornwall and a later arrival into Friday morning. Meanwhile, line segments will also be possible in other parts of Wales and SW England with locally strong gusts of wind given the presence of a strong LLJ - with a spell of strong winds likely for a time in E Devon and S Dorset.