Local snowfall amounts near 15 centimetres are possible in the heaviest snow squalls.
Snow squalls will weaken this evening.
Intermittent snow squalls will continue into tonight and Friday.
Environment Canada says flurries this morning are expected to intensify into snow squalls later this morning bringing with them heavy snow and reduced visibilities.
Lake effect snow squalls off Northern Lake Huron are occurring today.
Highways 400, 69, 17 and 11 are likely to be affected.
Conditions are favourable for lake-effect snow squalls from Lake Huron and Georgian Bay beginning late this morning.
Strong and gusty southwesterly winds are also expected to whip up the freshly falling snow, resulting in very low visibility in blowing snow.
Snow squalls cause weather conditions to vary considerably; changes from clear skies to heavy snow within just a few kilometres are common.