Moderate Risk of Severe Convective Gusts Wales, Central and Eastern Regions 06Z-18Z
Slight Risk of Isolated Short Tracked Tornadoes UK as per red box
Risk of Thundery Showers later in period as per yellow box
Sharpe and probably unseasonal 'Ana' cold front expected to develop within the wake of a weaker upper feature by early morning Tues. UKMO fax charts show a typical rapid forward progress with streamlines at an acute angle to the orientation of the frontal boundary. Models show very moist air lifted abruptly upward and into the upper layer of the atmosphere with a dry incursion lower down at 700mb. Strong subsidence looks to follow on behind the cold front where further strong gusting is likely to develop. These conditions are typically associated with 'ana' type cold fronts. Convective gusts are calculated with a maximum strength of around 60kt where some minor structural damage may occur within the strongest embedded convective cells.
There will also be a slight chance for an isolated brief tornado event or two between segments as per red box. This risk zone is calculated based on the likely occurrence of strong dynamic lift close to the baroclinic zone close to surface where forward rolling vorticity can be lifted into the vertical where updrafts are strongest. The nature of this type of development puts the strongest shear values low down within the storm cell and hence any low level mesocyclone development is likely to be short lived but quite intense. The red box ATM suggests the potential for these conditions to come together more efficiently than the broader risk zone assessed (white box)
Worth remembering that the prime risk for Tues is born directly from the energy within the lowest layers with cloud tops not necessarily that high or even needed to be high to develop severe weather. Hence the risk of thunder, apart from region just east of Irish Sea look to be rather sparse. Though can't rule out the odd sferic!