Thundery showers are likely to move northwards into some southern parts of England during Saturday morning, becoming more widespread and heavy over central UK through the course of Saturday and overnight into Sunday morning.
Please be aware of the risk of local disruption to transport and outdoor activities. In particular, be aware of the potential for some spray and standing water on roads, and the possibility of road closures.
This warning has been updated to include more of southern UK, as well as starting the warning period slightly earlier. Please monitor for further updates.
A frontal zone associated with very warm and moist air will move northwards during Saturday. It will become slow moving over central areas of England and Wales later Saturday, persisting overnight, before slowly easing away to the east during the course of Sunday morning.
There remains a lot of uncertainty in where the heaviest and most prolonged thundery showers will occur, with some places in the warning area having only small amounts of rain, However, there is a risk of some locally large rainfall totals, with 25 to 50 mm of rain possible in places.The public is advised to take extra care, further information and advice can be found here: http://www.metoffice.gov.uk/public/weather/warnings/