Heavy downpours have swept across much of the UK with more rain to come this weekend as well as thunderstorms and gusts of 60mph.
Yellow warnings for rain and wind have come into force as the unseasonable weather caused widespread disruption.
Several festivals and events have already been cancelled, and motorists and commuters have also been told to avoid travelling if possible.
The Met Office said the rain moved into parts of Northern Ireland, Wales and north west England overnight and would be followed by heavy showers and thunderstorms.
Meteorologist Bonnie Diamond said: "There has been a lot of rain over the last 24 hours with more heavy showers to come on the way today and tomorrow.
"So we will certainly see an impact in terms of localised flooding, difficult driving conditions and transport delays."
A rain warning for much of the country is valid until midnight on Friday and two separate warnings of strong winds have been issued for Friday afternoon and all of Saturday.
The first wind warning up until midnight on Friday affects west Wales, Devon and Cornwall, to parts of the Channel coast.
The areas under threat on Saturday in the second wind warning include the whole of Wales and southern and central England as far north as Blackpool, Huddersfield and Grimsby.
Antrim in Northern Ireland was worst hit overnight, drenched by 39mm of rainfall - the largest amount in the 12-hour period between between 9pm on Thursday and 9am on Friday.
The national August average is 97.4mm.
Shap in Cumbria recorded 38.6mm - more than half of England's August average of 69mm, with Gwent in Wales clocking 34.8mm - a third of the country's 107mm August rainfall average.
The Met Office is urging people not to travel in some parts amid fears of flooding and trees being toppled by the intense gales.
A Met Office spokesman said: "There is some fairly heavy rain and thunderstorms from Bristol, up through Wales and into Northern Ireland. That will transfer eastwards over the next few hours, causing poor driving conditions in places."
Neil Armstrong, chief meteorologist at the Met Office, said: "This low-pressure system will bring challenging conditions, including unseasonably strong winds and heavy rain, from the west during Friday and Saturday.
"Summer storms - compared with those in autumn and winter - always have the potential to create additional impacts because more people are likely to be outdoors, especially by the coast.
"Additionally with trees in full leaf they are more vulnerable to being brought down by strong winds."
Richard Leonard, head of road safety at Highways England, urged drivers to "consider if their journey is necessary".
"In high winds, there's a particular risk to lorries, caravans and motorbikes so we'd advise drivers of these vehicles to slow down and avoid using exposed sections of road if possible," he said.
The RNLI has warned those visiting the coast to beware of large waves and storms.
Despite around 1,500 residents recently being allowed home after the damaged Toddbrook Reservoir was deemed safe, the warnings are also in place at Whaley Bridge.
Derbyshire Police confirmed if the water reached a "level of concern, the residents in the evacuation zone will be the first to know".
Ahead of this weekend, Boardmasters Festival, in Newquay, was called off on Wednesday and other events have been scaled back, including Houghton, a Norfolk dance music festival.
The weather will improve across much of the country by Sunday, apart from northern England where thunderstorms are forecast.