Happy New Year!
A highly amplified jet stream pattern across North America this week will lead to a rapidly strengthening storm off the United States’ East Coast midweek, which will take dead aim at Atlantic Canada Thursday into Thursday night with heavy precipitation and powerful winds.
A sharp temperature gradient caused by the Arctic air mass to the north/west and the milder, ocean air to the east will help feed this potential monster of a storm. This storm will also likely tap into some tropical moisture, which will likely increase precipitation rates across Atlantic Canada.
The big question is the track of this storm. Latest information favors a center track up into southwestern Nova Scotia Thursday night and then across PEI Friday morning. If this track holds, then we can expect the heaviest snow to fall from Down East Maine through southern/central/eastern New Brunswick and across western PEI. In these areas, there is the potential for 30-50 cm of snow and blizzard conditions.
Obviously, with all that snow and wind (gusts in excess of 80 km/h) there will be tremendous blowing and drifting of snow. Farther south and east, there would be accumulating snow followed by a change to ice/sleet and perhaps rain over a large portion of Nova Scotia, eastern PEI and up into Newfoundland. If the storm tracks up over eastern Nova Scotia, then we get the heavier snow into northern/western Nova Scotia and eastern PEI.
1. Storm peaks in intensity Thursday evening with the center pressure of the storm potentially dropping into the 940-950 mb range.
2. The storm begins to occlude as it moves up over Nova Scotia, which may lead to a significant dry slot coming up into central/eastern Nova Scotia Thursday overnight, which may quickly shut down the precipitation for a period of time.
3. This will be a large storm with impacts felt through New England, where we may also see blizzard conditions over southeastern New England with the potential for 6-12 inches of snow (highest on Cape Cod).
4. Mariners should pay close attention to forecasts as this storm has the potential to be a big wave producer with hurricane-force wind gusts offshore.
5. Worst of the storm for the Maritimes looks to be Thursday afternoon through Thursday night.
6. This is the type of storm that could cause power outages, so be prepared for that!
7. There may be a narrow band of significant ice for a period of time during the height of the storm Thursday night. Too early to know where this may occur, but current trends favor northern/western parts of Nova Scotia and possibly a portion of PEI.
8. This storm will be a miss for Ontario, though the piece of energy coming in from the west to help trigger the ocean storm may be enough to bring a small accumulation of snow to southern/eastern Ontario Wednesday afternoon.
9. Montreal and Quebec may get 2 to as much as 8 cm of snow Wednesday night into Thursday.
We will be issuing a more detailed snowfall forecast map either later today or Tuesday.
Fairly dry pattern across much of the rest of the nation, except for the lake-effect snow belts as the cold air continues to pass over the warmer lakes.
Speaking of lakes, Lake Erie went from 19 percent to 36 percent ice coverage over a two-day period this weekend. Based on the current forecast, I expect ice cover to rapidly expand across the lake over the next week. As the ice expands, there is less open water and thus the risk for heavy lake-effect snow off Lake Erie is reduced. Another blast of Arctic air may invade the Prairies early next week then possibly expand into the east by midweek.
Signs of a significant January thaw for the eastern half of the country have been tempered as more ridging is showing up over Alaska and NW Canada the second week of January, which argues against much of a warmup for the east, more likely back toward normal. Fairly quiet pattern in the west for the long range.