December's arrival is bringing a messy mix of rain, wind and potentially heavy snow to southwestern Ontario.
Environment Canada elevated a special weather statement to a snowfall warning for Sarnia-Lambton Monday afternoon.
The weather agency said an intense low pressure system will produce a multi-day rain and snow event into Wednesday. Total snowfall amounts could range from five centimetres to 15 centimetres in Sarnia and from 15 centimetres to 40 centimetres, six to 16 inches, in parts of north and east Lambton County.
With temperatures around the freezing mark, Meteorologist Peter Kimbell said accumulations will depend on how much of the precipitation falls as rain instead of snow.
"It's mostly going to affect areas inland, not so much the City of Sarnia and areas near Lake Huron," said Kimbell. "So I think probably five to 10 [centimetres] is a better estimate for what would fall over the City of Sarnia and near the lake."
Kimbell said greater snow amounts will fall in the county with Monday afternoon's forecast calling for 10 centimetres to 15 centimetres Monday night and another 15 centimetres to 25 centimetres Tuesday afternoon and Tuesday night.
As well strong northwest winds gusting to 70 kilometres an hour will create some lake enhancement off of Lake Huron.
The St. Clair Region and Ausable Bayfield conservation authorities have issued flood watches, warning of the potential for storm surge, and possible flooding and erosion along the Lake Huron shoreline, particularly Old Lakeshore Road in the Bright's Grove area.
Residents are reminded to avoid watercourses and flooded areas due to slippery banks and cold, swift moving water.
