Intense Polar Vortex Brings Chilly Temperatures Across the US
A surge of arctic air from Canada has ushered in the coldest weather of the season for much of the United States. This phenomenon, called a polar vortex, is expected to deliver subzero temperatures to the Midwest, Mid-Atlantic, and even parts of the South.
Moreover, it appears that we could face more arctic blasts in the years ahead.
Research published in the journal Environmental Research: Climate indicates that cold air outbreaks from the Arctic will continue across the Northern Hemisphere in the coming decades, despite the region warming at a faster rate than the rest of the globe.
According to Accuweather, strong winds are anticipated from Montana to Nebraska this week, with freezing temperatures advancing eastward toward significant cities such as Philadelphia, where daytime highs may barely climb into the upper teens.
Impact of the Stratosphere on Earth’s Weather
The polar vortex is a massive circular weather pattern in the Arctic that surrounds the North Pole. This typical winter pattern usually traps the coldest air close to the pole.
Normally, the jet stream serves as a dividing line that keeps the polar vortex confined to the Arctic, but at times segments of the vortex can drift southward, leading to unusually chilly conditions in the U.S., Europe, and Asia.
The following visuals illustrate how even climate changes occurring in distant mid-latitudes can trigger a release of arctic air over the United States weeks to months later.
Polar Vortex and Jet Stream Shifting Southward into the US
According to the National Oceanic and Atmospheric Administration’s Global Forecasting System model, the polar vortex is projected to move south of the tropospheric jet stream over North America, which corresponds to the elongation of the polar vortex.
Understanding the Stratosphere
To comprehend the structure of the atmosphere, we identify the troposphere, which extends approximately 6 miles above the Earth and is the layer where most weather occurs. The stratosphere lies between 6 and 31 miles above the surface and contains the polar vortex.
Due to limited sunlight, both poles of the Earth are significantly cooler than the equator. This cold, dense air accumulates in the polar regions, resulting in a powerful jet stream developing within the stratosphere that drives the frigid air eastward. This robust circulation system is what we refer to as the polar vortex.
This article was revised to correct a typo.
CONTRIBUTING Anthony Robledo
SOURCE NOAA, Climate.gov, NASA, and the Royal Meteorological SocietyThis article was updated to include additional information.