Convective Outlook: Tue 18 Dec 2018
LOW
SLGT
MDT
HIGH
SVR
What do these risk levels mean?
Convective Outlook

VALID 06:00 UTC Tue 18 Dec 2018 - 05:59 UTC Wed 19 Dec 2018

ISSUED 21:02 UTC Mon 17 Dec 2018

ISSUED BY: Dan

At the beginning of the forecast period, an active cold front will be straddling eastern Ireland to the Hebrides. Strong shear and upper forcing will encourage pronounced line segments initially, with locally squally conditions, but as the upper forcing tends to relax with time the line convection will begin to fragment and weaken as it continues to migrate eastwards across the Irish Sea and into western Scotland. That said, some elements of less-pronounced line convection are still expected to persist as the cold front continues to move eastwards across England, Wales and Scotland, but not as intense as earlier in the day.


The post-frontal environment is then characterised by cold mid-levels overspreading relatively warm SSTs, as the Atlantic upper trough continues to nudge eastwards across the British Isles. A few hundred J/kg CAPE are expected to build, with numerous showers developing over open seas and moving farther inland on the southwesterly steering winds. A few lightning strikes and small hail will be possible with the strongest cells - the risk initially over western Ireland during Tuesday daytime, but extending to other portions of the LOW threat level during Tuesday evening and night.