Convective Outlook: Tue 14 Sep 2021
What do these risk levels mean?
Convective Outlook

VALID 06:00 UTC Tue 14 Sep 2021 - 05:59 UTC Wed 15 Sep 2021

ISSUED 05:36 UTC Tue 14 Sep 2021


As an upper trough lifts gradually northeastwards from Pembrokeshire to the North Sea during Tuesday, pulses of heavy rain will develop and affect large portions of England in particular through the day. Forecast profiles are saturated with a cold undercut at the surface, and so overall the risk of any lightning is generally quite low and largely dependent on sufficient surface heating in the afternoon hours in the wake of any cloud/rain to coincide with the upper trough axis and steepest mid-level lapse rates. Therefore the main focus will be over southern England, the south Midlands into East Anglia / SE England but it is quite likely extensive cloud will limit surface heating and therefore little convective interest develops. Nonetheless, some very heavy rain is possible in some areas given a warm, moist airmass and forcing aloft.

Thunderstorms are much more likely to develop over northern France where better insolation and higher surface temperatures are likely, and the remnants of these could pass close to east Kent later in the day. Some shallow showers are also likely over parts of Ireland during Tuesday daytime as well.