Convective Outlook: Sat 13 Aug 2022 |
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What do these risk levels mean? |
VALID 06:00 UTC Sat 13 Aug 2022 - 05:59 UTC Sun 14 Aug 2022
ISSUED 06:44 UTC Sat 13 Aug 2022
br> br>ISSUED BY: Dan
Mid-level heights will slowly fall on Saturday as an upper low to the west of Iberia drifts northeastwards to become located broadly over the western English Channel by 06z Sunday. Cooling aloft will occur progressively northeastwards above a hot, dry and deeply mixed low-level airmass in place across much of the British Isles. The net result is steepening mid-level lapse rates, the leading edge near the Scilly Isles at 06z Saturday and then generally expanding erratically northwards across Ireland and western Britain through Saturday and Saturday night. As such, pockets of AcCas with bases typically around 11,000-14,000ft will be possible associated with this environment, with the potential for elevated showers from very high cloud bases to semi-randomly develop at times depending on subtle forcing/moistening aloft. Most model guidance suggests many areas will remain dry/void of showers, but the thermodynamic environment would support the potential for a few. The greatest mid-level instability will often be located near the Scilly Isles and broader western English Channel area closest to the approaching upper trough, and so perhaps the best chance of a few high-based showers/thunderstorms will be in this area. Given the magnitude of instability present above the EML, lightning could be quite active for a time with any cells that do manage to develop. A marginal SLGT has been introduced, primarily for the overnight period.