Millions of Brits have been warned of thunderstorms set to hit this weekend, amid fears of flooding of homes and businesses in some areas.
The Met Office put out the yellow alert covering the majority of Scotland and England, starting at 9am on Saturday. People have been warned of the possibility of lightning strikes, hail and strong winds.
The rain is feared to develop into fast flowing or deep floodwater, putting people's lives at risk. Some rural communities could become cut off as a result of the water so residents have been urged to prepare for tomorrow's deluge.
The warning by the Met Office reads: "Heavy showers and thunderstorms are expected on Saturday, during the morning mainly over parts of England before becoming mainly focused over northern England and Scotland by late afternoon/evening.
"Some intense downpours are likely and whilst rainfall accumulations will vary from place to place, as much as 50 mm of rain could fall in a short space of time in some locations. Hail, lightning and gusty winds will be additional hazards."
Power cuts are also expected as a result of the extreme weather, which could also cause spray on the roads.
A separate yellow warning for thunderstorms is in place today for Northern Ireland between 11am and 6pm.
Meanwhile a return to blistering temperatures is expected from today as forecasters predict the mercury to soar as high as 30C this weekend.
Experts say Friday will be a 'very warm and sunny day for many' although there are warnings it will remain wet and windy for some regions in the northwest.
Giving his verdict for Friday, Met Office deputy chief meteorologist Dan Harris said: "Temperatures will be on the rise from Friday, as a plume of very warm air drifts across the UK from the south.
“Parts of east and southeast England may reach 29 or 30C on Friday, with mid-twenties more widely across England and Wales. By Saturday, this heat will have extended further north, with parts of Scotland also reaching the mid to high twenties, and again around 30C or perhaps even a touch higher for inland parts of eastern England."
The soaring temperatures prompted the Met Office to issue a heat health alert for six regions around the UK.
A yellow alert has been issued across London, the South East, East Midlands, West Midlands, East of England, Yorkshire and the Humber.
The alert, issued by the UK Health Security Agency and the Met Office, is currently in place from 12pm until 9am on Sunday.
Temperatures could go up to 27C or 28C today before climbing to 30C on Saturday, forecasters have said.
A yellow alert means that any impacts likely include the increased use of health care services by vulnerable populations and an increase in risk to health for individuals over the age of 65 or those with pre-existing health conditions, including respiratory and cardiovascular diseases.
Areas affected by Saturday's yellow warning
Central, Tayside & Fife
Angus
Clackmannanshire
Dundee
Falkirk
Fife
Perth and Kinross
Stirling
East Midlands
Derby
Derbyshire
Leicester
Leicestershire
Lincolnshire
Northamptonshire
Nottingham
Nottinghamshire
Rutland
East of England
Bedford
Cambridgeshire
Central Bedfordshire
Essex
Hertfordshire
Luton
Norfolk
Peterborough
Southend-on-Sea
Suffolk
Thurrock
Grampian
Aberdeenshire
Moray
Highlands & Eilean Siar
Highland
London & South East England
Bracknell Forest
Buckinghamshire
Greater London
Kent
Medway
Milton Keynes
Oxfordshire
Reading
Slough
Surrey
West Berkshire
Windsor and Maidenhead
Wokingham
North East England
Darlington
Durham
Gateshead
Hartlepool
Middlesbrough
Newcastle upon Tyne
North Tyneside
Northumberland
Redcar and Cleveland
South Tyneside
Stockton-on-Tees
Sunderland
North West England
Blackburn with Darwen
Blackpool
Cheshire East
Cheshire West and Chester
Cumbria
Greater Manchester
Halton
Lancashire
Merseyside
Warrington
SW Scotland, Lothian Borders
Dumfries and Galloway
East Lothian
Edinburgh
Midlothian Council
Scottish Borders
West Lothian
South West England
Gloucestershire
Strathclyde
Argyll and Bute
East Ayrshire
East Dunbartonshire
East Renfrewshire
Glasgow
Inverclyde
North Lanarkshire
Renfrewshire
South Lanarkshire
West Dunbartonshire
Wales
Flintshire
Wrexham
West Midlands
Shropshire
Staffordshire
Stoke-on-Trent
Telford and Wrekin
Warwickshire
West Midlands Conurbation
Worcestershire
Yorkshire & Humber
East Riding of Yorkshire
Kingston upon Hull
North East Lincolnshire
North Lincolnshire
North Yorkshire
South Yorkshire
West Yorkshire
York