Update: The high risk of thunderstorms has been removed for Southeast England as confidence has much reduced as poor cross-model agreement. The enhanced risk of thunderstorms has also been removed for the east coast too.
...Southwest England, Wales, West Midland...
Elevated thunderstorms are likely to sweep across parts of Dorset, Devon, Bristol, and Gloucester in the evening toward night. MUCAPE is possible to reach 1500 J/kg with one or two convergence zone(s) developing across these areas. Significant downpours with hail are possible, with some places might see 20-30 mm of rain within 1 hour according to the latest AROME model forecast. Therefore a HIGH risk has been issued for these areas. The ENHANCED risk area has also extended to cover more parts of Southwest England, Wales, and parts of the West Midlands. There is somewhat suggestive of a squall line (or even two) will develop across Bristol Channel and extend north and southward during rush hours into the night, this might bring gusty wind, large hail, and frequent lightning to place with also a chance of few brief tornadoes developing, hence a SEVERE thunderstorm risk has been issued for parts of the west.
Updated at: 06:30 (BST) 05/09/2022
Update: The risk of thunderstorms has increased for parts of southwest England and Southeast England, therefore two HIGH risks have been issued for these areas.
...Southwest England, Wales, West Midland...
Elevated thunderstorms are likely to sweep across parts of Dorset, Devon, Bristol, and Gloucester in the evening toward night. MUCAPE is possible to reach 1200 J/kg with one or two convergence zone(s) developing across these areas. Significant downpours with hail are possible, with some places might see 20-30 mm of rain within 1 hour according to the latest AROME model forecast. Therefore a HIGH risk has been issued for these areas. The ENHANCED risk area has also extended to cover more parts of Southwest England, Wales, and parts of the West Midlands. A SEVERE thunderstorm risk has also been issued for Somerset, Bristol, Newport, etc... as heavy downpour is likely there.
...Southeast England, East Anglia...
Further bands of elevated thunderstorms are likely to bring impacts to the regions. Confidence has increased in these regions therefore a HIGH risk has been issued for Kent and Ipswich. MUCAPE is possible to reach 600-800 J/kg. Frequent lightning and 1-2 cm hail are possible for this region. A SEVERE thunderstorm risk has been issued for Kent as significant rainfall (20-25mm /hour) is possible there.
...Scotland...
There is a risk of thunderstorms developing there overnight but confidence is very low, therefore a SEVERE risk has been issued for these areas as strong thunderstorms are possible there.
Updated at: 16:40 (BST) 04/09/2022
A very complex forecast with low confidence with the exact location of the thunderstorm. We are expected to see two rounds of thunderstorms at night as a band of heavy rain reacts to mild southeasterly wind. Therefore a large slight risk and two areas of enhanced risk have been issued for parts of the south and east.
A band of heavy rain with push up from the Celtic sea to the west (Ireland, West Wales, Southwest England) in the afternoon, with the potential of a few thunderstorms embedded within it. Therefore a slight risk has been issued for these areas. However, the trailing cold front across England and Wales is expected to be fairly weak through most of the daytime hours as dry air overruns leaving just shallow moisture, which might limit lightning activity.
There is a sign of a convergence zone developing across northwest France and moving north/ northwest to parts of Dorset in the late afternoon, with CAPE of 800 - 1200 J/kg, creating a cluster of thunderstorms pushing inland, perhaps reaching the M4 motorway, which might create traffic issue in the rush hours. Therefore an enhanced risk of thunderstorms has been issued for parts of southwest England.
Into midnight, there is a sign of another convergence zone developing across Northeast England, with the potential of remaining bands of showers quickly developing into thunderstorms again. Some of them might develop across Scotland but confidence is very low. An enhanced risk has been issued for parts of southeast England and a slight risk for most of the east coast and parts of Scotland.
Issued at: 08:40 (BST) 04/09/2022
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