Convective Outlook: Wed 01 Jul 2020
What do these risk levels mean?
Convective Outlook

VALID 06:00 UTC Wed 01 Jul 2020 - 05:59 UTC Thu 02 Jul 2020

ISSUED 07:11 UTC Wed 01 Jul 2020


A gradually filling upper trough will swing eastwards across southern Ireland on Wednesday, its axis located over the Welsh/English border by 06z Thursday. Cloud breaks will allow pockets of insolation and heating of a moist low-level airmass to yield 100-300 J/kg CAPE, which combined with low-level convergence zones will aid in the development of scattered showers, some heavy. Across England and Wales, a warm nose at ~600mb will act as a mid-level cap, restricting the depth of convection and greatly hindering the potential for lightning. That said, as the upper trough slowly approaches the mid-level warm nose will begin to cool/erode, and it is possible late in the day that one or two showers may be able to grow taller and produce a few isolated lightning strikes - more especially Lincolnshire / Norfolk (15-20%).

A greater risk of lightning exists over southern Ireland (25%), due to deeper convection likely closer to the upper trough. However, CAPE will be rather skinny with weak shear and very moist profiles, which will serve to reduce buoyancy somewhat. There are also concerns over the extent of cloud cover, which may limit instability. The slack surface pattern and locally enhanced convergence/vorticity could aid in the development of a couple of funnel clouds.