Forecasters have placed much of southern England and Wales under a thunderstorm warning.
The yellow alert covering parts of Cornwall, Bath, Portsmouth, Swansea and Cardiff has been in place since 8pm last night and will remain in place until 8am this morning.
Meanwhile the second warning, covering London, Oxford, Gloucester and Chelmsford, will last until 10am.
The Met Office says thunderstorms are expected through the morning, before gradually clearing from the east, with some travel disruption and flooding possible.
There is a chance of of power cuts and damage to some buildings from floodwater, lightning strikes, hail or strong winds.
It comes as overnight fire crews were called to a lightning strike which damaged the roof at a residential care home in Alleyne Way, Elmer, at 1.44am.
Today’s forecast reads: “Early thundery rain across southern England and south Wales easing.
“Some bright spells developing, although further thundery showers may develop later.
“Some warm sunshine elsewhere, but chilly around North Sea coasts where there could be some low cloud.”
A risk of more thunderstorms remains tonight and tomorrow – but for the bank holiday weekend temperatures will be above average.
It comes as commuters face travel chaos this morning.
Lightning overnight damaged the electricity supply on several trainlines – while others have flooded.
National Rail listed a disruption between Westbury and Castle Cary – and minor delays are reported on South Western and Great Western railways.
Grey skies and wet weather meant April may have felt unusually cold, despite temperatures actually being higher than average for the time of year, the Met Office said.
Friday is set for a tea-time meltdown as a holidaymakers’ rush clashes with office workers and after-school traffic.
Around 16million drivers are expected on roads that day, data trends show.
RAC spokesman Rod Dennis said: “It’s looking like a Frantic Friday, with getaway, school and commuter traffic building into the evening.
“Major trunk routes will be congested, with Saturday also busy.
“And after such miserable cold temperatures recently, drivers are ready to make the most of any better weather.
“Expect many more people on roads on days temperatures rise.”
