Convective Outlook: Mon 16 Oct 2017
What do these risk levels mean?
Convective Outlook

VALID 06:00 UTC Mon 16 Oct 2017 - 05:59 UTC Tue 17 Oct 2017

ISSUED 21:30 UTC Sun 15 Oct 2017


An elevated mixed layer (EML) will reside across much of Britain, for a time at least, on Monday, gradually clearing NE-wards to the North Sea. This airmass is characterised by very steep mid-level lapse rates (some of the highest typically seen in the British Isles, even compared with during the summer months) atop very warm and dry air just above the surface. Some mid-level instability is likely, capable of producing some sporadic elevated showers or thunderstorms with very high cloud bases. Given the dry air below, amounts of rain at the ground are expected to be quite small.

A shower/storm is possible virtually anywhere, hence the broad LOW threat level, though the risk is generally quite low in any one location, and probably more likely during the morning and early afternoon hours, before dry air feeds in from the west throughout the vertical.

Meanwhile, the extratropical low, ex-Ophelia, will run NE-wards across the Republic of Ireland to western Scotland, bringing extreme wind gusts to exposed locations (especially southern Ireland) and very large waves. From a convective-standpoint, the environment will be strongly-sheared with high storm relative helicity values. Should any deep convection develop here (despite marginal instability), it is possible a few tornadoes could occur given backed surface winds and potentially low cloud bases - though in reality, it will be mostly stratiform rain here.