Thunderstorms are continuing to affect parts of Britain, with lightning and heavy downpours expected to hit both the morning and evening rush hours.
Torrential rain could cause some localised flooding, and people are being warned of the risk of disruption to power networks from lightning strikes.
A yellow weather warning is in place right through the day for large swathes of England and Wales, with the Met Office predicting a month's worth of rain could fall in some places in a matter of hours.
The intense conditions caused flash flooding in a coastal village in Cornwall on Tuesday, with some 50 properties affected and several people having to be rescued from their homes.
A council spokesman confirmed some properties in Coverack and one of the roads suffered structural damage and are due to be inspected by structural engineers.
Two people were rescued by a coastguard helicopter, and one witness described the flooding as "quite horrendous".
A meeting for residents, attended by council officers, will be held at a local hotel later.
Commuters in the Midlands and east of England could be caught up in downpours this morning, while those in north-east Wales and the North West will bear the brunt this afternoon, Steven Keates from the Met Office said.
"This morning it's probably going to be parts of the Midlands and eastern England that see potential for some heavy rain, some thunderstorms, and then a bit of a lull," he said.
"Then just in time for the evening rush hour, a different location, this time across parts of northern England, north-west England in particular by the looks of it, will see the worst of the weather in places."
He said the nature of the thunderstorms would be "hit and miss" and that the showers should move through the country "relatively quickly".
After a warm night, temperatures are expected to remain high on Wednesday for parts of eastern England where the mercury could rise to the low 30s, Mr Keates added.
Coverack flash flooding disaster compared to Boscastle as casualties winched to safety #Coverack #flooding #cornwall https://t.co/B21H67lTih pic.twitter.com/zTmI0myTNQ— Cornwall LIVE (@CornwallLive) July 18, 2017
Cambridgeshire police said the adverse weather conditions have caused problems with its non-emergency 101 service.
The force tweeted: "We are experiencing problems with the 101 lines due to the weather, 999 lines are ok you can also contact us via the website if you need us."
Water had to be pumped out of a number of properties in Tunbridge Wells, the fire service said, after it received more than 60 calls to the 999 line within one hour.
Crews from Kent Fire and Rescue Service attended but, despite two of the calls stating that people were trapped inside properties, no rescues were needed.