Environment Canada has revised a snow squall warning to a snow squall watch for north and east Lambton.
The weather agency says the area could see 25 to 45 centimetres or 10 to 18 inches of snow into Friday evening with brisk northwest winds gusting to 50 kilometres an hour.
Exeter weather radar shows a few snow squalls coming off Lake Huron to all shorelines just west of Grand Bend and northward with a broader area of moderate snowfall extending southeast of London.
These snow squalls will become more isolated in the afternoon.
All roads in the region are snow covered and whiteouts have been reported, especially in north and east Lambton, due to squalls and blowing snow.
Travel could be dangerous due to low visibilities.