Convective Outlook: Wed 04 Jul 2018
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Convective Outlook

VALID 06:00 UTC Wed 04 Jul 2018 - 05:59 UTC Thu 05 Jul 2018

ISSUED 20:07 UTC Tue 03 Jul 2018


Elongated upper low will drift across the British Isles on Wednesday, gradually merging with the larger-scale Atlantic upper trough. The focus initially will be on pockets of elevated convection over S and SW England during the morning hours, although with weak instability any lightning activity should be fairly isolated. By the afternoon, strong surface heating and low-level convergence (due to the slack surface flow) will shift the focus to surface-based developments - primarily over S + E Ireland, Scotland into N England, and S / SW England into S Wales and the S Midlands. A few isolated showers may develop, the convection perhaps deep enough locally for a few lightning strikes - though the marginal instability, weak shear and sparse coverage precludes the issuance of a SLGT. Isolated showers may continue to develop during the evening hours, particularly near M4 corridor / S Wales, though most will generally decay overnight as nocturnal cooling commences. Main threats will be locally high rainfall totals, given slow movement of showers and very dry ground - especially so on roads where dust deposition on the road surfaces over the past few weeks may make conditions rather slippery.