The United States is set to experience the coldest wave of Arctic air this season, marking the 10th polar vortex invasion of an unusually chilly winter. According to meteorologists, an amalgamation of various Arctic weather patterns is poised to propel the cold air, typically contained around the North Pole, into not just the United States but also Europe.
This winter has been atypical, with meteorologist Judah Cohen, of Atmospheric and Environmental Research, noting that the frequency of polar vortex episodes has soared well above normal levels. Generally, the polar vortex might dip southward two to three times in a typical winter, but this season's unusual meteorological phenomena have been marked by extremes from record snowfalls in New Orleans to wildfires in Southern California.
The latest cold snap is expected to begin impacting the northern Rockies and northern Plains this coming Saturday, with the icy conditions persisting throughout the week. The cold will be concentrated primarily east of the Rockies, sparing only central and southern Florida and parts of the far American west.
Forecasts anticipate the average low across the contiguous United States to drop to approximately 16.6 degrees Fahrenheit on Tuesday, slipping further to 14 degrees Fahrenheit by Wednesday, according to meteorologist Ryan Maue. With biting winds forecasted, wind chills could plunge to even harsher levels. With the exception of Hawaii, California, and Florida, every state is likely to experience wind chills dipping below 20 degrees Fahrenheit at some point during the week.
The states of Kansas, Nebraska, Missouri, and Iowa are expected to face some of the most intense cold, with temperatures diving up to 35 degrees Fahrenheit below typical January averages, as per the Weather Prediction Center's Zack Taylor. Predictions from NOAA indicate that states from Oklahoma to Michigan may see lows plunge below zero. While the specifics are yet unclear, there is potential for accompanying storms, possibly a nor'easter, during this cold spell.
This instance of the stretched polar vortex differs from events where sudden warming weakens the vortex and discharges cold air; here, the vortex remains intact and robust, elongating to deliver a bitter chill to the U.S. Cohen explains that despite being historically less severe than a full-scale vortex breakdown, this stretch is still expected to deliver significant cold to the nation.
Meteorologists are eager to uncover patterns causing the frequent stretching of the polar vortex this winter, though some experts, like Laura Ciasto of NOAA, speculate it might just be a rare meteorological anomaly. Meanwhile, Denmark's climate researcher, Martin Stendel, suggests that although noteworthy, such occurrences are not unprecedented.
Compounding this atmospheric setup, a high-pressure system over Greenland is modifying the path of the jet stream, the fast-moving air current that orchestrates storm systems. This alteration encourages the frigid air to drop and persist across affected regions. Stendel also highlights the potential role of anthropogenic climate change in amplifying the waviness of the jet stream, making these cold waves more common.
Despite the aggressive cold impacting much of the United States, global temperatures continue their upward trend. January recorded yet another high, reinforcing the fact that we remain on a generally warming trajectory despite local deviations.