Following thunderstorm activity overnight around Kent and the Irish Sea, another outbreak is anticipated later today across more central and northern parts of England. As emphasized many times, storms are likely to be sporadic and therefore not everywhere will see them. The risk remains greatest this afternoon across the north Midlands, NE Wales, and much of Northern England. Large thunderstorms may develop by the early evening, perhaps producing frequent lightning, hail and a risk of flash flooding in places.
The following risk map has been issued for today, valid until 3am Saturday.
Do remember this is just a risk map, and is designed to highlight the areas most at risk, i.e. with the greatest probability. Therefore, everywhere within the highlighted areas experience a storm, and so many will remain dry this evening.
The UK Met Office also have a yellow weather-warning in force for central and Northern England, Eastern Scotland and Northern Ireland which reflects the risk of intense storm activity.
Detail
Significant surface heating through the course of Friday under a shallow trough will create plentiful instability across central and northern England with CAPE values of 1,500 to 2,000 j/kg expected. Any storms that may develop later on Friday therefore have the potential to amass significant size and intensity. Although multi-cell clustering is favored with these parameters, some supercell development is possible given the presence of very high CAPE and weak Helicity / Shear. Storms may also become long lasting as the upper level trough migrates north east wards. The shallow nature of the trough means that any convection may be slow to arise, and there is a slight (~25%) risk of non-initiation. A greater likelihood, however, is that some significant storm activity will develop favored by the unstable parameters; with the potential for severity to be somewhat limited due to the relatively high medium level pressure values. Nontheless, storms which develop may produce large hail, strong winds and funnel cloud activity. High rainfall totals of up to 50mm are also possible with this storm activity.