With the arrival of Storm Babet, severe weather warnings for wind and rain will be in place for much of this week.
The second named storm of the season will last from Wednesday to Saturday, the Met Office said, and is expected to cause flooding, power outages and travel disruption.
Over the four days, yellow warnings were issued for large parts of the UK, including large parts of Scotland, eastern Northern Ireland, north-east England, Yorkshire, the East Midlands and East Anglia.
Up to 150 to 200mm of rain is expected to fall in central and eastern areas of Scotland and there is a chance of gale-force winds of 70mph hitting northern parts of the UK, forecasters have warned.
Scotland typically receives 168mm of rainfall in October, but within a few days the country will receive more than this amount.
The heavy rain may also lead to “fast flowing and deep flooding” which could pose a “threat to life” and there is also the possibility of vital services such as gas, water and mobile phone signals being disrupted.
Parts of England can expect more than 100mm of rainfall during the week, with some remote areas getting up to 150mm.
As the storm approached on Tuesday, forecasters said gale-force gusts could occur along the coasts of Wales and southwest England, as well as higher areas to the west such as Dartmoor in south Devon and Eryri in northwest Wales.
Stephen Dixon, a spokesman for the Met Office, said: “A period of unsettled weather is ahead.
“There are some high levels of rainfall that have the potential to disrupt travel plans… the possibility of power outages as well as the obvious threat of flooding.”
“If you look at Wednesday, the first burst of rain is likely to impact Northern Ireland, Wales and the south west of England in particular and into Thursday.
“But as you move from Thursday into the week, the shift is more concentrated in central and eastern Scotland, but also some central and eastern areas of England.”
He added that the Met Office was likely to announce further weather warnings in the coming days.
David Morgan, flood protection officer at the Scottish Environment Protection Agency (SEPA), said: “Storm Babet will bring heavy rain and strong winds across Scotland from Wednesday evening, starting in the south-west before moving into the north-east through Thursday into the weekend.
“Flood warnings and warnings will be issued as necessary and we continue to work with the Met Office to monitor the situation around the clock.”
The Royal National Lifeboat Institution has urged the public to exercise “extreme caution”, particularly on exposed cliffs, waterfronts and piers.