Polar air moves east to put the b-r-r-r in November across Maritimes

Waves crash off the coast of Nova Scotia on Saturday, November 30 2019. (CTV)

On the heels of the latest rainy weather system to cross the Maritimes comes chillier November weather. The prolonged period of below seasonable temperatures is a result of an early outbreak of polar air south across the continent.

Rain reports

For parts of the Maritimes, the slow-moving weather front that arrived Sunday night into Tuesday has produced the heaviest rainfall in months.

The heaviest rain moved up the Eastern Shore of Nova Scotia and into Cape Breton. Weather station and volunteer rain reports coming in as high as 70-to-90-plus mm of rain. A band of steady rain that also contained downpours and brief thunderstorms crossed southwest to northeast in New Brunswick. That produced totals of 20-to-40 mm. Areas in the Maritimes that experienced lighter rain included parts of northern Nova Scotia, southeastern New Brunswick, and Prince Edward Island.

Rain continued to fall in Cape Breton on Tuesday. Another round of rain and showers will move in off the Atlantic for Nova Scotia and Prince Edward Island Tuesday evening. Additional rain amounts of five-to-15 mm are possible except in Cape Breton where another 20-to-30 mm may fall for some areas. Cape Breton, with the exception of northern Inverness County, remained under a Rainfall Warning as of Tuesday afternoon.

Snow showers for some

It is a cold front cross the Maritimes. The front marks the boundary between the milder air that accompanied the rain and the leading edge of the polar air that is working east across the country.

That polar air contributed to the first significant snowfall of the season for both Ontario and Quebec. It also dove deep south into the United States, bringing snow to the mountains of Tennessee and the Carolinas as well as triggering a freeze warning for northern Florida.

The colder air will trigger snow showers for parts of the Maritimes Tuesday night into early Wednesday morning. While snow accumulation should be very limited in most cases, some greasy surfaces developing at higher elevations is possible. Areas that should watch for that include any of the roads and highways that climb into higher terrain in northwestern New Brunswick. The higher spots of the Annapolis Valley escarpment in Nova Scotia could also see a bit of accumulation. The roads and highways that pass through the Mount Thom areas could get a bit slick. The highest terrain of the Cape Breton Highlands will also see some wet snow.

Chilly November weather

Once the polar air moves into place over the Maritimes, it looks like it will stick around for several days.

A developing trough (southerly dip) in the jet stream will allow for that chilly air to be refreshed out of northern Quebec on the weekend.

The expected temperatures aren’t anything too out of the ordinary for November but will run a bit below averages. Expect high temperatures in the low-to-mid single digits for most areas through early next week. Overnight low temperatures will fall towards or a few degrees below freezing.

While an early season snow event such as what occurred in Ontario and Quebec isn’t appearing in long range forecast guidance yet, having the chillier air in place increases the chances of one happening. If you haven’t yet changed over to your winter tires, you may wish to consider doing so.