Environment Canada is watching a major storm system that's expected to impact southern Ontario Wednesday and Thursday.
A low pressure system intensifying over the southern U.S. will track northeastward, bringing rain and significant snow to some areas, along with the possibility of freezing rain.
Where the heaviest snow will fall and areas at risk of freezing rain will depend on the track of the low which remains uncertain.
The forecast for Sarnia-Lambton right now calls for periods of snow or rain through Wednesday and periods of snow and blowing snow on Thursday.
The national weather agency has a special weather statement in effect at this time.