Convective Outlook: Tue 24 Sep 2019
LOW
SLGT
MDT
HIGH
SVR
What do these risk levels mean?
Convective Outlook

VALID 06:00 UTC Tue 24 Sep 2019 - 05:59 UTC Wed 25 Sep 2019

ISSUED 05:55 UTC Tue 24 Sep 2019

ISSUED BY: Dan

A rather complex pattern will evolve on Tuesday, as a series of low pressure centres dumbbell around each other beneath a broader upper trough. The first low will be strongly forced, with an organised area of intense rainfall expected to swing northeastwards across England and Wales during Tuesday morning, with embedded sporadic lightning possible - and hence pinpointing specific areas where lightning is most likely to occur very difficult. However, with fairly saturated profiles, rather weak instability and marginal mid-level lapse rates, any lightning with this first area of rain will probably fairly localised. Nonetheless, strong gusts of wind will be possible, along with localised flooding.


By midday and through the afternoon, a clearance is possible across CS England / S Midlands, enabling better heating of the residual low-level moisture (14-16C dewpoints). This combined with some low-level confluence and the passage of the trough axis aloft will likely lead to scattered heavy showers developing and moving northeastwards. Lightning activity is questionable given somewhat restricted convective depth and fairly weak shear by the afternoon hours, but some sporadic lightning is possible and a low-end SLGT has been issued to cater for this risk.

Another area of interest where some localised sporadic lightning may occur is SW Scotland / NW England, where low-level convergence will become maximised to aid forced ascent during the afternoon and early evening hours. A low-end SLGT has been introduced, but confidence in much lightning occurring is not particularly high.