Convective Outlook: Fri 25 Jun 2021 |
|
What do these risk levels mean? |
VALID 06:00 UTC Fri 25 Jun 2021 - 05:59 UTC Sat 26 Jun 2021
ISSUED 07:06 UTC Fri 25 Jun 2021
br> br>ISSUED BY: Dan
An upper trough will disrupt over the UK/Ireland on Friday, with a cut-off upper low sliding southwards to be located over the Celtic Sea by 06z Saturday. At the surface, a humid airmass is present with dewpoints of 14-15C across East Anglia and SE England. Frontal rain associated with a cold front, initially over the Midlands / Cen S England, will migrate eastwards to East Anglia / SE England while fragmenting, the wrap-around occlusion providing a persistent area of rain over northern England, southern Scotland and north Wales. The potential for deep convection remains unclear, and appears tied strongly to the requirement for sufficient surface heating. Extensive cloud may inhibit this, while a marked dry intrusion will also spread across Wales, SW / Cen S England and the Midlands through the day - and this may act as a capping inversion if surface temperatures are unable to increase to near or above 20C. As a result, there is much uncertainty over how much deep convection can evolve, weaker capping over East Anglia / SE England but likely more extensive cloud limiting surface heating, while better clearance but potentially more capping in central/western Britain.