A slop storm will push into eastern Canada later tonight and through Tuesday. It's not a big storm, but with cold, dry air in front of it, there will be an assortment of precipitation types from southern Ontario through the St. Lawrence Valley.
You can also follow my commentary on the storm on my twitter... @BrettAWX
Currently, the air across southern Ontario is cold and very dry (low dewpoints) which does give me concern that the initial burst of precipitation across southwestern Ontario late this evening could be something other than the rain that the models are showing, though the southerly winds should eventually bring in enough low-level warming for a mostly rain event from Hamilton to London and Windsor.
For the GTA, I think this starts out as a light snow/sleet mix then goes over to freezing rain away from the lake, while Toronto itself will turn to rain. Precipitation should change back to snow Tuesday morning for areas just north/west of Toronto as the upper-level temps cool, while in Toronto itself it may take until late morning or early afternoon.
Precipitation should eventually change to rain across the St. Lawrence Valley thanks to the southeast downslope winds, but not before a prolonged period of mixed precipitation.
I do think areas from basically Barrie on north should stay mostly snow with a chance of a little mixing.
The storm system should strengthen as it approaches the Maritimes, and I can easily see a general 8-15 cm of snow across the northern half of New Brunswick Wednesday morning, while mixed precipitation and rain will impact areas down toward Saint John.
Weekend Storm totals for Atlantic Canada from very intense storm
Moncton, NB 27 cm
Saint John, NB 24 cm
Bathhurst, NB 21 cm
Miramichi, NB 20 cm
Gander, NL 18 cm
Deer Lake, NL 18 cm
Sydney, NS 15 cm
Yarmouth, NS 14 cm
Greenwood, NS 6 cm
Halifax, NS 4 cm
Still waiting for PEI totals
Highest wind gusts
Wreckhouse, NL 170 km/h
Grand Etang, NS 161 km/h
Burgeo, NL 124 km/h
Brier island, NS 115 km/h
Some needed rainfall for southern Ontario this week.
Mild air masses likely to outnumber the chilly air masses for a good part of October.
Jet stream pattern across North America will become amplified across North America into next week, which means more extremes in weather.
Warm weather will dominate in the eastern half of the country for the next week. Pattern change possible during the last week of September.
The jet stream will strengthen from the Pacific across southern Canada over the next 1-2 weeks which will keep any sustained chilly/cold air masses up across western Alaska and eastern Siberia.
The latest clues to the long range into the month of October.