VALID 06:00 UTC Fri 01 Jul 2016 - 05:59 UTC Sat 02 Jul 2016

ISSUED 20:33 UTC Thu 30 Jun 2016

ISSUED BY: Dan

Broad upper trough sharpens as it crosses the British Isles on Friday, with cold air aloft steepening lapse rates in response to diurnal heating. Expect scattered showers to form widely through the day, extending in coverage southwards and eastwards with time, with a few thunderstorms also likely. Best instability will be found across parts of Scotland, Northern Ireland and Ireland (a few hundred Jkg^-1 MLCAPE), but here shear will be weaker. A better overlap of marginal instability and strong DLS (40-60kts) should be present across north Wales / north Midlands / northern + eastern England, and so here better organisation of cells seems likely.