Parts of Tayside have been issued with an upgraded amber warning for rain.
Some areas could see a month’s worth of rainfall in just a day between Thursday and Friday.
The Met Office had already issued a yellow warning for wet weather covering most of Dundee, Angus, Perthshire and Fife from 3pm on Thursday until 6pm on Friday.
However, forecasters have issued a separate amber warning – the second-highest level of alert – covering most of Angus and areas of eastern and northern Perthshire.
It comes into force at midnight on Friday, running until 3pm.
Experts say it is “likely” that homes and business will be flooded and fast-flowing or deep floodwater could pose a “danger to life”.
Trains cancelled
The weather led to several incidents on Thursday including the railway line between Dundee and Aberdeen closed due to flooding.
Scotrail laid on shuttle buses instead as the flooding affected the line between Laurencekirk and Stonehaven.
Road conditions are also understood to be responsible for two crashes.
A lorry landed on its side on the Emmock Roundabout on the A90 at Dundee.
Two lorries were also involved in a collision on the A94 near to Balbeggie.
Speed restrictions on several railway lines
In response to the forecast, speed restrictions are being imposed from 6pm on Thursday until noon on Friday on the lines between:
- Dunblane and Gleneagles
- Aberdour and Burntisland
- Perth and Ladybank
- Laurencekirk and Portlethen
Meanwhile trains will run at slower speeds from 9pm on Thursday until 10am on Saturday between:
- Perth and Dunkeld & Birnam
- Pitlochry and Blair Atholl
ScotRail says journey times will be extended as a result.
Perth and Kinross crews on standby for flooding
A tweet from Perth and Kinross Council said: “There is likely to be standing water on some roads so please drive with extra care.
“We will have crews on standby so will try to help if your property is at imminent risk of flooding.
“If lines are busy a please call back later.
“If you know you are at risk from flooding please take precautions to protect your own property.”
Flood warning for River Isla at Coupar Angus
Meanwhile environment agency Sepa has issued a flood warning for the River Isla at Coupar Angus.
It says: “Prolonged rainfall on to saturated ground during Thursday and continuing into Friday may result in a rise in river levels higher than those experienced during Tuesday.
“Flooding of low lying agricultural land remains possible.
“Sepa will continue to monitor the situation and further updates will be issued as appropriate.”
🌧️ Some parts of eastern Scotland may see as much #rain in the next 24-36 hours, as they'd typically expect to see during an entire average November
Here's a look at how much rain is expected today and tomorrow 👇 pic.twitter.com/9kKYj1Zqdm
— Met Office (@metoffice) November 17, 2022
Warnings have also been issued for the Bridge of Ruthven to Leitfie and Aberbothrie areas.
Lower-level flood alerts are also in place for Dundee, Angus and Fife.
Met Office spokesman Oli Claydon said: “We’ve got an area of low pressure that is quite slow moving, the same area of low pressure that brought quite a lot of rain to the south east of the UK today and is now moving up the east coast of the UK.
“Later on Friday that rainfall should start to ease as low pressure moves away.”
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