Environment Canada has added more details to a special weather statement for Southern Ontario including Niagara which warns there is the potential for significant snowfall starting tomorrow night into Saturday.
The national weather service says a Colorado low is expected to bring a large shield of snow with it.
The system typically brings 15 to 20 centimetres of snow, and this is not expected to be an exception to the rule.
Latest indications suggest 15 to 20 cm of snow may fall near and north of a line from near Grand Bend - Waterloo Region - Peterborough - Ottawa by Saturday evening.
In areas closer to Lakes Erie and Ontario, including the Golden Horseshoe, the snow may change over to rain for a few hours, limiting snowfall amounts to the 5 to 15 cm range.
But there is some uncertainty over the exact track the storm will take, which could affect how much snow we get.