Conducive setup sees nor'easter on the table for Atlantic Canada
Models are showing a nor'easter will be targeting parts of Atlantic Canada this week. We have a first look at how things could play out.
December could start off on a stormy note for Atlantic Canada.
Forecasters will be closely watching the threat for a nor'easter for Atlantic Canada on Tuesday night and Wednesday. Impacts include intense wind gusts, heavy rain and hefty snowfall, though exact amounts and locations are uncertain as the forecast continues to evolve.
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A Gulf low is expected to develop early this week and then track to the Mid-Atlantic states, then rapidly intensifying as it tracks over the Atlantic Ocean on its way to Canada's East Coast.
Folks should brace for localized power outages, transportation issues, and ferry and bridge delays and/or closures.
Nor'easter in development this week
A nor’easter is brewing for Atlantic Canada. A deep trough of Arctic air is settling across the heart of North America.
An embedded wave across the central U.S. will continue to track east, while some moisture and energy from the Gulf of Mexico stream ahead of the approaching trough.
By Tuesday morning, the ingredients for the storm have moved across the Atlantic Ocean, setting the stage for impressive intensification.
Storm ingredient checklist:
Strong, upper-level support: A powerful jet stream lifts across eastern North America on Tuesday, deepening surface pressure
Energy streams merging: Moisture and instability from the Gulf of Mexico phase with the digging trough, further enhancing lift
Ample, cold air supply: Just ask Ontario and Quebec on Monday as cold air increases the available temperature gradient for storm development
-Warm ocean temperature: Heat and energy from the Gulf Stream can release energy, further fuelling the storm
More importantly, where is this nor’easter going?
Models on Saturday were confused and uncertain, but on Sunday, models narrowed the range of solutions to a track that scrapes across the coast of Nova Scotia early Wednesday morning, before crossing eastern Newfoundland in the late day.
A track close to the coast means mixing and heavy rainfall threats increase along the coastline, but where temperatures remain at or slightly below freezing just inland, heavy, wet snow will occur.
The system is tapping into Gulf of Mexico moisture, so there will be plenty of it.
This system is pulling moisture in from the Gulf of Mexico, so the system will be moisture-laden. Regions that don’t experience wet snow will have the risk of more than 40 mm of rainfall.
Storm timeline
On Tuesday evening, periods of light snow develop across the Maritimes, increasing in intensity as the night progresses.
The rain-snow line will likely gradually lift north, marking a messy transition zone. Winds will increase.
By Tuesday overnight and pre-dawn hours Wednesday morning, low pressure passes directly south of Nova Scotia, building strong winds along the coast and heavy precipitation, including wet snow inland. Periods of light snow begin across Newfoundland.
During the day Wednesday, the low drifts southeast of Sable Island, with a band of lingering snowfall across the Maritimes on the backside. At the same time, heavy, wet snow increases along the warm front across much of Newfoundland.
Messy and wet snow expected across central Newfoundland while the Maritimes begins to see improving conditions late-day Wednesday. A wintry mix is on tap for the Avalon Peninsula with varying types and precipitation totals.
Stay with The Weather Network for more information and updates on your weather across Atlantic Canada.