Convective Outlook: Tue 25 Feb 2020
LOW
SLGT
MDT
HIGH
SVR
What do these risk levels mean?
Convective Outlook

VALID 06:00 UTC Tue 25 Feb 2020 - 05:59 UTC Wed 26 Feb 2020

ISSUED 22:08 UTC Mon 24 Feb 2020

ISSUED BY: Dan

Broad upper troughing covers the British Isles on Tuesday, sharpening and sliding southeastwards during Tuesday night. The associated cold pool overspreading relatively warm SSTs (and diurnal heating inland!) will generate a few hundred J/kg CAPE in an environment with very steep mid-level lapse rates. Numerous showers are expected throughout this forecast period, primarily focussed over western areas initially but developing more widely as the upper trough slides southeastwards with time. Several shortwaves will also provide the focus for more enhanced activity as they drift southeastwards in the mean flow.

One such feature will be close to western Ireland first thing on Tuesday morning, drifting towards Wales / SW England by midday and then across southern England / Midlands during the remainder of the afternoon and evening. This will be strongly forced in an environment with strong shear, helping organisation of cells and it is quite like sporadic lightning and hail will occur with this activity. Ahead of this, a strip of vorticity coupled with diurnal heating may allow a separate line/zone of showers to develop and drift across the Midlands / southern England / East Anglia / SE England during the first half of the afternoon, and this could also produce some sporadic lightning.

Another shortwave will enhance shower activity towards NW Ireland on Tuesday evening, eventually approaching western Scotland during the early hours of Wednesday. Away from these more organised features, random scattered showers will still occur capable of producing a few isolated lightning strikes - particularly over NW England. Strong, gusty winds will be possible with the most intense showers - particularly in southern and western Ireland towards SW England, and it is in these areas that an isolated tornado may also be possible. Eastern Scotland and NE England will see very few showers, and could stay largely dry.