Parts of Lambton County are included in a snow squall watch issued by Environment Canada Tuesday.
The weather agency says westerly winds continue to generate off lake snow in areas east of Lake Huron and Georgian Bay.
A cold front passing through southern Ontario Tuesday night will bring even colder conditions with winds becoming northwesterly.
The shift in wind direction will direct the snow squalls southeasterly, possibly impacting north and east Lambton.
For areas including Strathroy, London and St. Thomas the greatest threat of squalls will begin Wednesday morning and continue throughout the day.
Forecasters say snowfall accumulations of 10 to 20 cm per 12 hours are likely under the heaviest streamers.
The gusty winds will cause very poor visibility due to blowing snow.