Convective Outlook: Fri 28 Aug 2020

LOW SLGT MDT HIGH SVR

What do these risk levels mean?

Convective Outlook

VALID 06:00 UTC Fri 28 Aug 2020 - 05:59 UTC Sat 29 Aug 2020

ISSUED 06:20 UTC Fri 28 Aug 2020

ISSUED BY: Dan

On Friday, Britain and Ireland sit underneath a broad upper trough/low with the main jet activity displaced to the south. Cold air aloft atop initially relatively warm SSTs, and then diurnal heating inland, will yield 500-700 J/kg CAPE across the English Channel and central/southern Britain. Numerous showers are likely over the English Channel in particular initially, but many others will develop inland through the day - particularly aided by low-level convergence zones (such as southern England) near the surface trough axis. Beneath the upper low, shear will be fairly weak and so pulse-type showers/storms are moist likely, their outflow then enabling daughter cells to develop nearby. Some small hail may be possible in the most intense cells, and enhanced vorticity near convergence boundaries may bring the risk of a few funnel clouds or weak waterspout/tornadoes. Small surface low over the North Sea near Norfolk could also be the focus of some sporadic lightning into East Anglia as it drifts south during the afternoon and early evening hours.