The overall pattern across the United States and southern Canada will be shifting as we get closer to next week. The jet stream, which steers storms across the country will be shifting south and strengthening, allowing for a stormier pattern in the eastern part of the U.S. and Canada starting the end of this week and into next week.
Before I get to that, we still have that weak clipper running across south-central Canada and this will continue to spread some light snow into parts of Ontario and Quebec into Wednesday (see map below).
Snow into parts of the East Saturday night through Monday morning
A weakening storm will track into the Great Lakes on Sunday. Moist air coming up from the south ahead of the storm will overrun a colder dome of air to the north, resulting in a persistent band of light to occasionally moderate snow from parts of Ontario through Quebec later Saturday night into early Monday morning.
While this will certainly not be a big storm, I could certainly see some spots from northeastern and eastern Ontario through southern Quebec picking up anywhere from 5 to 10 cm during the period as the high pressure area to the north supplies the cold air.
This storm should be mostly or all rain in the Kitchener to Toronto to Peterborough to Kingston areas unless the low ends up being forced more to the south which is still possible.
Potential major eastern coastal storm next week.....
Computer models are starting to come in line showing a major storm potentially hugging the Northeast U.S. coast either Tuesday or Wednesday of next week before taking aim at the Maritimes.
Obviously, we are still many days away from this event and there is still plenty of uncertainty on the exact track, timing and intensity, but I will say that the overall upper-level pattern shaping up across North America supports the idea for a significant storm amplification along or just off the Northeast U.S. Coast.
One thing that I am confident about is that there will not be any fresh cold air in place ahead of this storm, so if you are looking for snow the storm is going to have to produce its own pocket of cold air, which would likely occur north and west of the storm track and most likely across the interior Northeast if it intensifies rapidly just off the coast.
Currently this looks like a situation of heavy rain and strong winds along the Northeast U.S. coast, including the major cities and up into Nova Scotia with the potential for a change to snow on the backside of the storm.
Farther inland, it also likely starts as rain but goes over to snow much more quickly as the storm deepens just off the coast. This is especially possible over the higher terrain of the Appalachians as the area could end up with a heavy, wet snowstorm all the way up into western New Brunswick and likely southern Quebec..... maybe parts of eastern Ontario.
I just took a look at the new 12z ECMWF model and it shows a strengthening nor'easter tracking from eastern North Carolina to just south of Cape Cod between Wed and early Thursday next week and then northeast after that.
You can follow me as usual on my twitter @BrettAWX
Fast, west-to-east jet stream pattern across southern Canada into next week.
Clues to the long range over the next several weeks across North America.
Potential for significant rainfall over southwestern Alberta late this week into the early weekend.
A strong, upper-level storm system will bring significant rain, severe thunderstorms and much cooler air to parts of western and central Canada into early next week.
Latest ideas on the weekly long range through the end of this month.
No sustained heat from southern BC into the central Prairies over the next week or two.