Up to one foot of rain could pour down across the UK in just 24 hours as Britons are warned to brace for "life-threatening" flooding.
Storm Babet is set to bring heavy rain across areas of Perthshire and Aberdeenshire later today.
A series of weather warnings are in place, including a red warning issued for "exceptional rainfall and impactful wind" in the east of Scotland.
The Met Office has also issued yellow weather warnings for east England and parts of Scotland with chaotic conditions expected until 12pm on Saturday.
The near-record amount of precipitation is expected to bring a month's worth of rain, along with gusts of up to 70mph, which could leave some people cut off for days.
Low pressure, which formed off the coast of Spain and Portugal in the Atlantic last week, could cause "extensive flooding to homes and businesses and severely disrupted travel conditions".
David Morgan, Flood Duty Manager for the Scottish Environment Protection Agency (SEPA), said: “Storm Babet will bring heavy rain and high winds across Scotland from Wednesday evening, starting in the southwest before moving across to the northeast through Thursday and into the weekend.
“Impacts from surface water and rivers are likely, and with catchments saturated from recent heavy rain and flooding, we’re urging people to be prepared for potential flooding.
"There is also concern that surface-water flooding may be exacerbated by debris blocking drainage, culverts, etc. as a result of the high winds.
Its red warning - the first issued since Storm Dennis in February 2020 - covers parts of eastern Scotland from 6pm today until 12pm tomorrow.
A Met Office spokesperson said: "There is now high confidence in exceptional rainfall falling across southeast Grampian, particularly the uplands of Angus and south Aberdeenshire.
"100-150mm of rain is expected to fall widely within 24 hours with some locations likely to see 200-250mm of rain which is expected to cause considerable impacts both where it falls and lower lying areas further east."
The red warning - the first issued since Storm Dennis in February 2020 - covers parts of eastern Scotland from 6pm today until 12pm tomorrow
Met Office
The wet and windy weather caused travel chaos earlier this morning as trains between London and the West Country were delayed due to the weather.
High winds also brought trees to the ground in southern counties such as Sussex, as well as huge waves on the coast of Devon.
However, the worst conditions were felt in Ireland, where people were urged to completely avoid the town of Midleton after it suffered the "worst flooding in living memory".
