A developing area of rain is expected to reach the south of England early on Thursday morning, before pushing north across much of southern UK during the day. The rainfall is likely to be heavy and thundery at times, with the potential for torrential downpours in places.


An area of low pressure is expected to develop just to the northwest of Spain in the next 12 to 24 hours. This system is then expected to push north across Biscay and into the south of the UK early on Thursday. With very warm air entrained into the system, locally heavy and thundery rain is likely to develop as the system pushes across parts of England and Wales. 15 to 30 mm of rain is possible in in 6 to 12 hours, with as much as 50 mm possible very locally by the end of Thursday.

The development of this system is very complex, and uncertainty in the details of this event is relatively high. As such this warning will be updated in the coming days as confidence increases.
The public should be aware of a significant risk of very localised disruption to travel due to surface water flooding. Lightning may be an additional hazard.

On Friday an area of locally heavy rain already across many central and southern parts of England and east Wales at the start of Friday, is expected to push across the rest of England and Wales during the early morning. Rain is likely to be persistent, and may be accompanied by hail and thunder in the south and east. Rain will ease from the west during the evening, and probably become confined to eastern areas by the end of Friday.