Frigid air that typically remains confined to the Arctic region is making its way into the United States, resulting in an extended period of unusually cold temperatures. This chilling phenomenon is not expected to break any records, but it will certainly prompt shivering among those affected.
Meteorologists are observing that such cold air outbreaks, referred to as the polar vortex, are becoming increasingly common, and intriguingly, this trend seems to be linked to a warming planet. The term, which once had a more technical definition, has now become part of mainstream weather discourse. For those living in the regions touched by this cold front, the immediate experience is simply one of significant chilliness.
The root of this cold snap lies in the behavior of the jet stream, which is essentially a high-altitude, fast-flowing river of air that plays a critical role in steering weather patterns. Currently, the jet stream is taking an undulating route from the Pacific Northwest down to the Southeast, remaining in this distorted trajectory. Meanwhile, areas to the west, such as California, are enjoying warmer and drier conditions, while parts of the east are feeling the brunt of arctic-like temperatures.
Dan DePodwin, director of forecast operations at AccuWeather, explains that a substantial influx of cold air from Canada and the Arctic is driving these plunging temperatures. He predicts that many regions in the eastern U.S. will experience temperatures that fall 12 to 25 degrees Fahrenheit below their historical averages. The most severe impacts are expected in states such as Kansas and Washington, where recent snowfall will coincide with plummeting overnight lows that could dip into the single digits or even below zero, particularly in the Ohio Valley and the Great Plains.
Judah Cohen, who heads seasonal forecasting at Atmospheric and Environmental Research, describes this event as a manifestation of the polar vortex stretching out. He likens the polar vortex to a rubber band – when it’s relaxed, its shape is somewhat circular, but pulling on it creates an elongated form. This stretching can lead to a relocation of cold air, forcing it down into the U.S. or pushing it towards Asia.
In addition to this stretching phenomenon, occurrences of sudden stratospheric warming can cause the polar vortex to destabilize and drift southward, sometimes even splitting. However, Cohen clarifies that this is not the scenario at play right now.
Some experts caution, however, that the term polar vortex is often misinterpreted. The actual polar vortex exists about 20 miles up in the stratosphere, while the current cold air plunge is situated at lower altitudes.
Recent research suggests that such polar vortex disruptions are becoming more frequent, indicating a change in weather patterns over time. According to Jennifer Francis, a scientist at the Woodwell Climate Research Center, the rapid warming of the Arctic—occurring at four times the rate of the rest of the planet—alters the temperature gradient between the north and south, exacerbating changes in the jet stream. These shifts result in what Cohen describes as a more pronounced and wavy jet stream, influenced by less sea ice in Arctic regions.
Despite this current wave of cold, global winters have warmed by an average of 1.1 degrees Fahrenheit over the past quarter-century, based on National Oceanic and Atmospheric Administration data. As DePodwin points out, it is entirely plausible to experience cold snaps alongside warmer overall winter temperatures. He emphasizes that while climate change contributes to rising average temperatures globally, it does not eliminate the occurrence of colder weather events.
In summary, current weather patterns illustrate a complex interplay between localized cold outbreaks and broader trends in climate change, serving as a reminder that while temperatures can fluctuate, the overall trajectory indicates a warming world.
