Parts of Angus could be hit with up to 26 hours of heavy rain.
The Met Office has issued a yellow weather warning from 10pm on Tuesday until the end of Wednesday.
The warning covers northern Angus including Brechin, Montrose and Arbroath.
Forecasters are warning slow-moving rain could lead to disruption on the roads and public transport.
Homes and businesses could also be flooded and some communities may be cut off.
Heavy rain in Angus could cause ‘danger to life’
Fast-flowing or deep floodwater may cause a “danger to life”.
Heavy rain is also forecast across Dundee, Perth, Fife and Stirling but these areas are not covered by the warning.
The Met Office alert says: “Areas of rain moving into northern Scotland from late Tuesday into Wednesday are expected to become heavy with some embedded showery outbreaks as the band slows down and focusses across the east coast and Moray Firth.
“(A total of) 20-30mm through the period is expected quite widely.
“However localised heavier bursts of rain likely to build totals toward 50-75mm with up to 90mm possible across Grampians and north-west Highlands.”
The alert comes as an area of low pressure brings colder-than-average temperatures to the UK at the start of July.
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