Convective Outlook: Mon 13 Aug 2018
What do these risk levels mean?
Convective Outlook

VALID 06:00 UTC Mon 13 Aug 2018 - 05:59 UTC Tue 14 Aug 2018

ISSUED 09:20 UTC Mon 13 Aug 2018


UPDATE 09:20 UTC SLGT removed from Sussex given lack of lightning activity this morning, while extended a little NW-wards across N England for this afternoon in light of latest guidance

Upper trough axis over eastern England first thing Monday morning will migrate eastwards to the Baltic Sea by Tuesday morning. Cold air aloft atop SSTs and diurnal heating will generate several hundred J/kg CAPE, with subtle forcing aloft and low-level convergence playing a key role in generating scattered showers, some capable of sporadic lightning. These will likely be ongoing at the start of the forecast period, especially over SE England and eastern English Channel - but by the afternoon the main focus will be eastern England. Slight warm nose at 700mb may cause some showers to struggle to maintain sufficient convective depth for lightning.

The strongest cells may produce small hail (pea-sized) and wind gusts up to 40mph. Slow storm-motion and elements of shower training may result in some local surface water issues. One or two funnel clouds may also be possible, enhanced by low-level convergence. Most showers will decay during the evening hours as daytime heating subsides and heights rise aloft.