Major winter storm on the way for Ontario and Quebec
Chris Scott, meteorologist
This will be the first widespread major winter storm of the season for Ontario and Quebec. Your local forecast has the specifics for your backyard, but this is a storm where the cliche ‘everything but the kitchen sink’ applies to what will be falling from the sky on Sunday. So it’s a good idea to get the big picture of what to expect.
Here’s the latest as of Friday afternoon:
- The storm is just beginning to organize east of the Rocky Mountains in Montana and Wyoming. It will start to develop a more distinct central area of surface low pressure (which you’ll be able to see on a surface weather map) by Friday night as it moves toward South Dakota and Nebraska.
- A reinforcing shot of very cold arctic air is flooding across the Prairies as the storm develops to the south; it was below -40°C this morning in extreme northern Saskatchewan.
- The storm will begin to tap into some Gulf of Mexico moisture on Saturday as it moves towards the Great Lakes, ending up close to Chicago by Saturday evening. The first snow from this system will begin to fall along highway 17 between the Sault and Wawa on Saturday afternoon.
- The main push of precipitation will move into Southern and Northeast Ontario later Saturday night into Sunday morning. This is where it gets tricky. Most communities in Southern/Northeastern Ontario and Southern Quebec can expect between 10-30 mm of precipitation. In places like the Sault, Sudbury, Kirkland Lake, and North Bay this will be all snow meaning that about 10-30 cm of snow could fall. In Southwestern Ontario, places like London and Kitchener can expect snow, wet snow, and a rain-snow mix – this will keep accumulations down, but make for a sloppy mess on Sunday.
- The Golden Horseshore, including Niagara, Hamilton and Toronto, will likely see a mixed bag of precipitation on Sunday. Areas north of the 401 in the GTA have a better potential for significant snowfall of 5-10 cm, possibly more toward northern York Region and Barrie. Going east of Toronto along the 401 to Kingston, ice pellets are more likely to mix in along with snow and possibly rain near Lake Ontario.
- The Ottawa and upper St. Lawrence Valleys will see a bit of everything falling from the sky (let’s just hope it’s not cats and dogs). Snow will begin Sunday morning, but will likely turn to ice pellets and freezing rain, and then to rain along the St. Lawrence including Montreal. Sunday will be a nasty day to drive along the 417 or 416 near Ottawa.
- Once this main pulse of precipitation moves through on Sunday, the cold air rushes in on the backside of the storm on the heels of north-northwest winds. This will set up snow squalls on Sunday night that will last into Tuesday off Lake Huron and Georgian Bay. Expect whiteout conditions in the snow belts, particularly on Monday. While it is too soon to say which communities will get the worst of these, the Monday commute around highway 400 may be impacted, and… and I hate to say it… London will likely get back into the squalls at some point on Monday.
- The Maritimes will see rain pushing in Sunday night with strong winds. There are indications that heavy rain may persist through Monday which may lead to localized flooding.
This type of storm is a nightmare for our forecast team trying to pin down the exact amounts of each type of precipitation and the timing. The story is pretty much set now, but keep an eye out for subtle changes in the track of this storm which may change the type of precipitation for your location.