Parts of south west Scotland could be battered by 10 centimetres of rain during the early hours of tonight.
Forecasters at the Met Office have warned torrential downpours could cause a "danger to life" from fast flowing rivers.
And they warned of a "good chance some communities cut off by flooded roads" in the worst affected areas.
An amber warning has been issued for south west Scotland from midnight tonight.
South west Scotland, along with the Borders and Lothian will be the worst affected of the regions.
The front is currently dumping heavy rain on northern England as it heads towards Scotland.
And up to five centimetres of rain could fall in a matter of hours at ground level.
Forecasters say ten centimetres could fall on higher ground.
"Homes and businesses are likely to be flooded, causing damage to some buildings," said a warning issued by the Met Office.
"Fast flowing or deep floodwater is likely, causing danger to life," it added.
The rain is expected to ease later on Thursday.
