The Met Office have issued a weather warning valid from 0400 on Friday until 2100 on Saturday.
They say,
Showers will become heavy and thundery across southwestern parts of England and Wales early on Friday, moving northeast to affect other areas south of The Wash to North Wales during the day. Some reduction in activity is expected overnight, 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.
Image: Kyle Simourd under CC BY 2.0