Convective Outlook: Fri 12 Jul 2019
What do these risk levels mean?
Convective Outlook

VALID 06:00 UTC Fri 12 Jul 2019 - 05:59 UTC Sat 13 Jul 2019

ISSUED 07:50 UTC Fri 12 Jul 2019


UPDATE 07:50 UTC A marginal / low-end SLGT has been introduced over SE Scotland / N England

An upper low will slowly retreat from the southern North Sea to Germany on Friday, with a trough axis sliding southwards across eastern Britain. Cool air aloft atop residual low-level moisture (dewpoints 13-15C) will steepen lapse rates and yield 300-500 J/kg CAPE in response to diurnal heating. Low-level convergence will likely aid the development of a few well-scattered showers and one or two thunderstorms by Friday afternoon / early evening, before decaying later in the evening as nocturnal cooling of the boundary layer commences.

Main focus will be over East Anglia late morning / early afternoon where a short window will exist for convection to grow deep enough, coupled with some reasonable shear, to produce lightning - before increasing subsidence aloft limits convective depth with time through the afternoon. As such, a marginal / low-end SLGT has been introduced. The attention will then shift to C / S Scotland and northern England during the afternoon and early evening.