The Met Office has identified 10 counties across the UK that are set to experience heavy rain tonight and into Wednesday (August 19). Rainfall rates could reach up to 32mm per hour in the worst affected areas.
Timing and spread of rain
At 7.30pm, light rain will be confined to Northern Ireland, parts of Wales and northern Scotland. By 9pm, rainfall will have spread across much of the Midlands, as well as Cheshire and Yorkshire. By around 1am, rain will have spread across virtually the entire area between Glasgow and London, with the heaviest downpours expected in Cumbria, Lancashire, Cheshire and Derbyshire.
These counties could see rainfall rates of up to 32mm an hour, classed as very heavy rain. Elsewhere, rainfall rates are expected to be between 0.5mm and 2mm an hour.
Short-lived downpour
The downpour will be relatively short-lived, with most areas expected to turn dry by 9.30am on Wednesday. Rain could linger for longer around Kendal, Leeds, Manchester and Sheffield.
The Met Office official weather forecast for the evening and tonight states: "Some sunny spells will linger across the far south this evening, but cloud will thicken from the west, with outbreaks of drizzle developing across much of England and Wales. Temperatures around average but staying warm in the far south."
Wednesday forecast and full list
The forecaster adds that on Wednesday, "rain will soon clear the far southeast, with sunny spells developing widely. Heavy, frequent showers across Scotland will spread more widely through the day, with some potentially turning thundery."
The sudden cool off comes just days after the country experienced another heatwave, with temperatures soaring to 38C. BBC Weather reports that the UK is set to get cooler with overnight lows of 3C in some areas. The forecast adds that rain will become heavier by Wednesday. However, it will "take weeks of above average rainfall into the autumn to make any significant changes to the drought", the broadcaster adds.
Full list of counties with predicted heavy rain (4-32 mm/h):
- East Ayrshire (Scotland)
- Dumfriesshire (Scotland)
- County Armagh (Northern Ireland)
- Carmarthenshire (Wales)
- Powys (Wales)
- Cumbria
- Cumberland
- Lancashire
- Cheshire
- Derbyshire
