Arctic Temperature Anomalies Expected in Northern Canada This Week

Arctic Temperature Anomalies Expected This Week

An amplified jet stream pattern is funneling unseasonably warm air into Northern Canada, with temperatures in parts of the Far North projected to climb 10 to 15 degrees Celsius above seasonal averages through the middle of November.

This persistent ridging pattern forces air to sink and warm as it descends toward the surface, creating a vast heat anomaly across the Northwest Territories and Nunavut.

Yellowknife Forecast Defies Seasonal Norms

The impact of this weather pattern is particularly visible in Yellowknife, where conditions are trending significantly warmer than historical data suggests. While a typical November 11th in the city sees a daytime high of -7°C and an overnight low of -12°C, current forecasts anticipate a high of 3°C and a low of -1°C.

Record-Setting Warmth in Ontario and Quebec

Meanwhile, southern Ontario and Quebec are experiencing a record-challenging heat event. Some southern Ontario communities are seeing temperatures climb into the 20s, and over the next five days some communities could have their warmest start to November on record, rivaling 1956 and 2022.

Daytime highs in these regions are expected to reach 10 to 16 degrees above seasonal norms on Wednesday, potentially marking the warmest temperature anomaly in the world for that day. The setup includes a strong, high-pressure ridge off the U.S. east coast and the warm front associated with a Colorado low flooding the region with warmer air.

Historical Context for November Heat

The current warmth invites comparisons to previous record-breaking November events. Pearson International Airport previously set a monthly record on November 5, 2002, when the temperature reached 25.1°C. Many cities in southern Ontario also noted their warmest start to November in 1956. Many overnight warmest-minimum temperature records for November are expected to be broken or challenged over the next two days in cities including Toronto, London, and Windsor.

Cooling Trends for Eastern Canada

The same atmospheric pattern driving the heat will eventually shift conditions for the eastern half of the country. By Thursday and Friday, daytime highs in Toronto, Ottawa, and Montreal are expected to dip a few degrees below seasonal averages as cooler air moves into the region.

Why Temperatures in Northern Canada Are Rising

Why are temperatures in Northern Canada rising so high?
A wavy upper-level jet stream has allowed a persistent high-pressure ridge to develop over the region. This ridge forces air to sink toward the ground, where it compresses and warms significantly before reaching the surface.

Will this warm weather last through the rest of November?
The current outlook has unusually warm temperatures through the coming week, with cooler air expected to dip into the eastern half of the country by Thursday and Friday.

Are these temperatures common for early November?
No, these temperatures are significantly higher than historical averages. For example, in Yellowknife, the forecast for November 11th sits 10 degrees above the typical seasonal high.

More on this story: Record November Heat Shatters Temperature Records in Québec · Early polar vortex disruption recorded with uncertain impact on Europe