The Polar Vortex Is Behaving Strangely. What It Means for the U.S.

An unusual disturbance has taken place in the polar vortex, though experts believe it will not result in extreme cold weather in the United States. The private meteorological firm AccuWeather has reported that the polar vortex is acting abnormally for this time of year, with high-altitude winds near the Arctic expected to slow down to 9 mph on November 3, compared to the average of 58 mph and the record low of 32 mph for the date.

Despite the significant disruption, forecasters do not anticipate the event to cause a major outbreak of Arctic air in the U.S.

The polar vortex is a vast area of low pressure and cold air encircling both Earth's poles, consistently present near them but varying in strength throughout the year. In the Northern Hemisphere's winter, this vortex can occasionally expand or become disrupted, allowing cold Arctic air to flow south along the jet stream, leading to unusually frigid conditions in the U.S. However, the polar vortex is currently weakening when it should be strengthening, and a critical factor for a significant Arctic blast in the U.S. is lacking.

There isn't enough cold air building up in Canada to be sent south, as most of the coldest air is now located over northern Russia.

This extraordinary atmospheric phenomenon might have little impact on weather conditions in the United States, according to AccuWeather meteorologist Tyler Roys. While temperatures are expected to decrease in some regions during the first half of November, this will be primarily due to local cold air rather than the polar vortex. AccuWeather believes that some of the most substantial temperature drops may occur in the Southwest.

The main factor preventing a major Arctic outbreak in the U.S. is the ongoing warmth in Canada. It is early in the cool season, and a high-pressure system has kept temperatures in the territories and northern prairie provinces 10-20°F above the historical average. This warm air is what the polar jet brings with it when it moves into the central and eastern U.S. As long as these regions remain relatively warm, the air will feel more like fall than the Arctic.

Conditions may become cooler during the second half of November, as the jet stream pattern could change enough to allow periods of colder air to move south later in the month and into December.