Convective Outlook: Sat 03 Sep 2022 |
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What do these risk levels mean? |
VALID 06:00 UTC Sat 03 Sep 2022 - 05:59 UTC Sun 04 Sep 2022
ISSUED 06:49 UTC Sat 03 Sep 2022
br> br>ISSUED BY: Dan
A sharp prefrontal trough will migrate gradually northwards across England into southern Scotland on Saturday. The low-level wind convergence along the trough axis, combined with modest heating of a moist low-level airmass (dewpoints 14-17C) yielding around 500 J/kg CAPE, will provide an environment increasingly favourable for scattered heavy showers and perhaps a few thunderstorms, especially with time (meaning northern England/southern Scotland at greatest risk, towards late afternoon and into the evening hours). There will likely be issues with mid-level capping restricting the depth of convection in places - and so lightning activity is questionable - but this should be less of an issue towards far northern England and southern Scotland. Here, reasonable speed shear and subtle veering with height may create an environment with around 30kts DLS, which may aid cell organisation for a time. Greatest threat for local surface water flooding is SW Scotland where multiple cells may train over similar areas. Eventual upscale growth into a band of rain is anticipated through the evening and night hours, and so lightning activity will likely wane. However, an uptick in elevated convection is possible in E / SE Scotland during the early hours of Sunday, spreading inland from the North Sea. Confidence is not overly high on much in the way of lightning occurring, but tentatively introduced a SLGT here.