The Met Office has issued a severe weather warning for the next 24 hours.
Showers will become heavy and thundery across southwestern parts of both England and Wales early on Friday, moving northeast to affect much of Wales, the Midlands, East Anglia and southern England during the day.
Some reduction in activity is expected on Friday night, before further slow-moving heavy and thundery downpours develop during Saturday, easing from the north later.
The public should be aware that the resulting downpours may lead to localised flooding and potential disruption to transport and outdoor events.
This warning has been updated to include much of north Wales where heavy thundery downpours are also likely today.