Jet pushes upper cloud south and surface pressure towards 1050 hPa
A warm front to the north of Scotland has already spread a veil of medium and high cloud across Scotland and northern England. I did think this would take most of Sunday, and that we would get away with at least a sunny morning, but already the sky is overcast with a layer of altostratus with some embedded patches of mammatus with in it, the base of which according to the Tain LCBR is at 9,000 feet. It’s not surprising that the high cloud has spread south so rapidly in the last few hours, as there was a 150 knot northerly jet at midnight down across the country.
It’s not only the spread of the upper cloud the jet is responsible for, surface pressure across South Wales is already close to 1047 hPa and still rising quite strongly at 09 UTC, so the 1050 hPa promised by the NWP models forecast looks very likely later today.