If you have anywhere to go on Friday or Friday night, Environment Canada warns it could be a treacherous drive.
It's issued a winter weather travel advisory, upgrading an earlier special weather statement.
The snow will intensify throughout the day on Friday, causing dangerous enough conditions for drivers, but near Lake Erie, there is also the risk of freezing rain.
"The snow may have a significant impact on the evening commute in more urban areas," warns Environment Canada. "Motorists should expect hazardous winter driving conditions and adjust travel plans accordingly."
Drivers should expect slippery road conditions and reduced visibility, especially in areas where the snow is heavier.
Residents can expect five to ten centimetres of snow, possibly more, before it tapes off late Friday night.