Convective Outlook: Sat 19 Dec 2020

LOW SLGT MDT HIGH SVR

What do these risk levels mean?

Convective Outlook

VALID 06:00 UTC Sat 19 Dec 2020 - 05:59 UTC Sun 20 Dec 2020

ISSUED 09:40 UTC Sat 19 Dec 2020

ISSUED BY: Dan

Negatively-tilted upper trough will slowly swing northeastwards across the British Isles on Saturday, with a significant cold pool aloft atop relatively warm SSTs. Steep mid-level lapse rates and 300-600 J/kg CAPE will drive numerous showers into exposed southern and western coasts, feeding well-inland on southwesterly steering winds and organised troughs/occlusions in the flow. The risk of lightning will generally be greatest close to the coast, where a few low-end SLGTs (25-30% chance) have been introduced. Many of the showers will likely produce hail and gusty winds, and given strong shear present across E / SE England on Saturday afternoon then this poses the threat for more organised convection further inland, with squally winds and hail possible.