The low pressure will further develop across the Celtic sea and is likely to move and settle in the west of Ireland for a couple of days this week. In this period, longer spells of heavy rain are likely across parts of Wales, southwest England, and Ireland, with a risk of heavy and thundery showers affecting other parts of England too. Strong winds are also likely in places especially across the seashore, perhaps with a risk of gales too.
There is potential for a shortwave feature is likely to develop across the southwest/central south on Wednesday night, which creates some cooling aloft and combines with temperature advection in 850mb, further creating mid/or elevated amount of instability, similar to Tuesday night.
The latest AROME and UKMO have suggested MUCAPE around 800-1000 J/kg in places across parts of central southern England and SW Ireland, allowing thunderstorms to break out in places.
This convective outlook is focused on Wednesday afternoon into Thursday afternoon, with high cross-model agreement and considering the MUCAPE and 850mb temperature, two ENHANCED risks have been issued; one across southern Ireland and NW Wales as sporadic thunderstorms are likely to develop in Wednesday afternoon into early night, perhaps further develop into one or two clusters of organised thunderstorms, a severe thunderstorms risk has been issued for parts of Ireland as gusty wind and prolonged heavy rain will bring driving difficulty and flooding. Another ENHANCED risk has been issued across parts of southern England and East Anglia. There is a high potential of cluster of thunderstorms breaking out across Somerset and Wiltshire as high instability is forecast, perhaps being severe in places, hence a severe thunderstorms warning has been issued for these areas, perhaps with risk of flooding as well. These cluster of thunderstorms might further develop into heavy rain in Wales and lose its convective as well, but sporadic lightning can not be rule out at all. Another cluster of thunderstorms might break out across Hampshire and West Sussex, pushing NNW into Lincolnshire and Norfolk overnight into early morning, perhaps reinforce in parts of East Anglia as well. Comparing to thunderstorms across the SW, the confidence for thunderstorms in the SE is relatively low, but according to the given unstable profiles, risks of severe thunderstorms cannot be ignored.
Another convective outlook for Thursday night to Friday will be issued on Wednesday night, as another similar shortwave feature will develop across parts of the south and Midlands.
Issued at: 18:00 (BST) 18/10/2022
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