Convective Outlook: Thu 05 Jul 2018
What do these risk levels mean?
Convective Outlook

VALID 06:00 UTC Thu 05 Jul 2018 - 05:59 UTC Fri 06 Jul 2018

ISSUED 08:07 UTC Thu 05 Jul 2018


UPDATE 08:07 UTC No major changes, tweaked the SLGT area to remove from Essex and extend a little farther east across Kent, based on latest guidance

The weakening upper trough over southern Britain will gradually clear eastwards to the nearby Continent on Thursday, as upper ridging builds more widely from the Atlantic. In general, rising heights will serve to inhibit deep convection - however, diurnal heating of residual surface moisture with dewpoints approaching 16-19C during the afternoon will yield up to (and locally in excess of) 1,000 J/kg CAPE, and combined with breeze convergence should aid in deep convection with the potential for a few isolated to well-scattered showers or thunderstorms in the afternoon and evening hours.

Have issued a low-end SLGT where there is best multi-model consensus, though some uncertainty over how much lightning there will actually be. Shear is rather weak, so pulse-type convection is expected, which will be fairly slow-moving given slack flow - leading to a risk of local surface water issues, especially given very dry ground present making roads particularly slippery following dust deposition on the road surfaces over the past few weeks. Such convergence-type setups can produce a few funnel clouds - though cloud bases will likely be quite high in this instance.