Friday-Saturday Eastern Canada Storms

The initial low pressure area will push into the Great Lakes region Friday and Friday night. This will initially bring some light snow or mix to parts of southern Ontario Friday which will likely change over to light rain from Toronto on southwest early Friday night, as the system kicks out any lingering cold air. Areas from Barrie to Peterborough to Ottawa on north should stay all snow with a few cm's possible by Friday night. The exception looks to be areas south of Ottawa to Kingston and areas north of lake Ontario where freezing rain or ice pellets is possible. I am also concerned about some mixed precipitation lingering into the early night over parts of southern Ontario with some pockets of low-level cold.

Farther west, confidence is higher for a significant snowfall, north of the primary low over northern Ontario and western Quebec.

Since the energy looks to remain split, the St. Lawrence River Valley looks to end up getting caught in between the two storms, which would put them in a more subsidence zone, resulting in lighter snowfall.

If the energy was to phase, then the coastal storm would end up stronger, would move slower and would get drawn farther north, resulting in higher snowfall across central and northern New Brunswick and PEI. However, the latest models have been shifting away from this scenario.

On the other hand, the shift in the track will send the heavier snowfall slightly farther south and across a large portion of Nova Scotia and southern New Brunswick. Some pockets may see a bit more than 30 cm, but generally the area should end up with 15-30 cm, as the storm moves along and does not stall. As for the Halifax, NS area I am currently expecting around 15 cm of snowfall accumulation at this time. 

Rain with some mixing may be possible along the south coast of Nova Scotia and temperatures may end up staying too warm for any falling snow to accumulate over the extreme southern tip of Nova Scotia. A slight shift in the track is all that is needed to change the precipitation type and amounts.

Behind the primary low there will be lake-effect snow east of the Great Lakes Saturday into Saturday night, before another clipper storm dives in from the west on Sunday followed by the arrival of the next Arctic blast early next week.