A yellow weather alert for rain is currently in force across some parts of Helensburgh and Lomond.
The Met Office warning kicked in at 6pm on Sunday and is due to continue until 9pm this evening.
The weather experts are warning of heavy rainfall bringing some disruption to travel.
People are warned that there is a chance that homes and businesses could be flooded, causing damage to some buildings.
Spray and flooding could lead to difficult driving conditions and some road closures throughout the area.
The Met Office said: "Further heavy rain will affect much of western Scotland through the rest of Monday.
"A further 40-75 mm of rain may fall quite widely on top of what has already fallen, most likely in parts of Argyll, Lochaber and Wester Ross, leading to a risk of some flooding and travel disruption."
We previously told that drivers were being warned about potential disruption on a major road due to the weather forecast.
As a precaution, Bear Scotland has announced that the Old Military Road local diversion route from the Rest and Be Thankful will be prepared.
Diversion of traffic onto the Old Military Road is now open and is continuing to facilitate traffic movements through Glen Croe as a precaution until Tuesday morning.
A hillside inspection on Tuesday morning will inform the decision to return traffic to the A83 at the Rest.
Ahead of the warning, Mark Franklin, Flood Duty Manager for the Scottish Environment Protection Agency (SEPA), said: “Persistent rain, heavy at times, is forecast in western Scotland on Sunday, becoming widespread on Monday.
“Flooding from surface water is possible on Sunday evening into Monday. River levels are also expected to be high overnight on Sunday into Monday and Tuesday, particularly around Speyside and Great Glen.
“We could see rivers reach the same heights as Storm Isha last month, but possibly higher in some locations. Travel disruption is possible, as well as flooding to land and properties.
“We have issued Regional Flood Alerts and continue to work with the Met Office to monitor the situation 24/7, updating Alerts and Local Flood Warnings as necessary.
“People living, working and travelling in affected areas are advised to consider any steps they need to take now to be prepared and stay safe, and to take extra care if they need to travel."
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