The Met Office has issued a fresh yellow weather warning, as some areas of the country could see as much as 75mm of rain in one day.
Parts of western Scotland are expected to be hit by the warning which is expected to kick in at 6pm tonight and last until 9pm tomorrow.
The regions expected to be impacted are: Perth and Kinross, Stirling, Highland, Dumfries and Galloway, Argyll and Bute, East Ayrshire, East Renfrewshire, Inverclyde, North Ayrshire, Renfrewshire, South Ayrshire, South Lanarkshire, West Dunbartonshire.
Forecasters warn of up to 75mm of rain is expected, with the areas in Lochaber, Argyll, the Trossachs and perhaps also Dumfries and Galloway expected to be hit the worst.
Large parts of Scotland have been issued with a yellow weather warning
Met Office
The Met Office said: "Heavy rain will bring the potential for some disruption across parts of western Scotland from Sunday evening, lasting through much of Monday.
"A slow-moving band of rain is expected to affect western, central and southwestern Scotland from Sunday evening, only slowly clearing during Monday.
"Widely 20-40 mm of rain may fall within the warning area, but 50-75 mm is likely to fall over the higher ground of Lochaber, Argyll, the Trossachs and perhaps also Dumfries and Galloway.
"Strong and gusty southerly winds will accompany the rain and there is the possibility of the odd rumble of thunder too."
LATEST DEVELOPMENTS:
Up to 75mm of rain is expected
PA
Locals have been cautioned of what to expect, with the forecaster warning: "Spray and flooding on roads probably making journey times longer. Bus and train services probably affected with journey times taking longer. Flooding of a few homes, businesses and campsites is possible."
Despite the stormy and wet weather, forecasters are predicting that many parts of Scotland will see high temperatures.
Aberdeen, Glasgow and Edinburgh are expected to see highs of 20C during the day and could see lows of 11C.
Although, some parts of the country such as the Scottish Borders could see a minimum of 12C with largely cloudy weather.
The weather warning will last from 6pm tonight until 9pm tomorrow
PA
Meanwhile other parts of the country are also set to see heavy rain, with the northwest severely impacted, while Wales will see some patchy rain and drizzle.
Elsewhere drier and clear spells are expected, in what is described by the Met as a "warm night".
Tomorrow will see a humid start with outbreaks of heavy rain persisting in Scotland and also in Northern Ireland.
The south will be drier accompanied with a hazy sunshine, as rain gradually sinks southeastwards.