Torrential downpours are expected to hit large areas of the country tonight as forecasters warn of flash flooding and lightning strikes.
With no prospect of a respite from the wet weather in sight, forecasters issued a series of severe weather warnings predicting heavy rain.
Met Office severe weather warnings are in place for north-east England and the Yorkshire and Humber areas from early this afternoon until 9pm.
Heavy rain was also forecast to hit the Grampian and Central, Tayside and Fife areas of Scotland early this evening between 4pm and 9pm.
Northern Ireland and western parts of Scotland are already subject to advisories warning of possible strong rainfall.
The East Midlands, East Anglia and the East of England were later added to the areas covered by the Met Office's severe weather warnings.
Up to 15mm of rain was expected in Norfolk, Cambridgeshire, Lincolnshire, Suffolk, Bedfordshire, Essex and Hertfordshire between 4.15pm and 7pm.
Leicestershire, Rutland and Northamptonshire, plus London and the south east, including Buckinghamshire and Oxfordshire were also urged to expect heavy rain before 6pm.
Billy Payne, forecaster with MeteoGroup, the weather division of the Press Association, said the rain risk from tonight's heavy showers might result in some flash flooding with the risk of lightning strikes.
She said: "This afternoon we've had heavy showers across the Midlands and long outbreaks of rain across Scotland.
"Overnight, Scotland will see quite a bit more rain to come, with some heavy showers.
"Most other areas should see showers becoming more scattered, particularly in the north west. It'll be quite a windy night everywhere, with some strong winds.
"There'll be more showers around tomorrow, but not quite as bad. Wednesday is not looking particularly nice. An area of low pressure from the south west will bring persistent and heavy outbreaks of rain across England and Wales."
Sections of the country endured a wet and windy start to the week as forecasters warned of more downpours to come.
Heavy rain overnight caused localised flooding and the Highways Agency warned drivers to take extra care using roads across much of England.
Up to 4cm (1.5in) of rain fell in areas of southern England in just a few hours - more than half the normal monthly total - and there were gale force winds in places.
Thorney Island in Hampshire saw the worst of the stormy weather with nearly 4cm of rain - half falling between midnight and 1am - and gale force eight winds (40mph).
Among the roads affected was the A249 in Kent where flooding forced the northbound carriageway to be temporarily closed between the junctions with the M2 and the A250.
This week's unsettled picture is bad news for families holidaying in Britain in the final weeks of the school summer break, including Prime Minister David Cameron who is in Cornwall with his family this week.
Average August rainfall in southern England is between 6cm and 7cm.