Convective Outlook: Sat 25 Aug 2018
LOW
SLGT
MDT
HIGH
SVR
What do these risk levels mean?
Convective Outlook

VALID 06:00 UTC Sat 25 Aug 2018 - 05:59 UTC Sun 26 Aug 2018

ISSUED 19:56 UTC Fri 24 Aug 2018

ISSUED BY: Dan

Broad upper trough will sit over the North Sea during Saturday, placing the British Isles on the rear-side under a northwesterly flow aloft. Cold air atop warm SSTs will steepen lapse rates and generate several hundred J/kg CAPE over the North Sea. A few scattered showers will likely push close to or just inland over Norfolk and E Suffolk on Saturday morning / early afternoon, which may produce a few lightning strikes - a low-end SLGT has been introduced to cover this risk, which should diminish by 14z.


Elsewhere, a few showers will likely develop but with weaker instability any lightning activity will tend to be rather isolated. That said, stronger shear will exist further west, which may be enough to compensate for the weak CAPE for some (limited) lightning activity - but in general, increasing subsidence will develop aloft as the afternoon wears on courtesy of upper ridging spreading from the west.

With surface winds easing towards Saturday evening, a few showers may develop during the evening / first part of the night in response to low-level convergence, anywhere from eastern Scotland down to East Anglia, mainly close to the coast and then drifting offshore. Lightning potential seems rather restricted given increasing capping aloft.