CAMBRIDGE — The frigid air that is expected to cause misery in our Mid-Atlantic region through the end of the month is being described by many weather forecasters as the polar vortex.
Have the forecasters just found another scary-sounding weather term (like cyclonic winds and derecho) to keep us tuning in? Or, as Rush Limbaugh recently suggested, is the term polar vortex being used by the liberal media as another “hoax” to validate the reality of global warming?
Most important, what the heck is a polar vortex and is it any different than the frigid “arctic clippers,” often called Alberta clippers, of winters past?
If it makes you feel any better (though it probably won’t make you feel any warmer), the frigid air now circulating over the Mid-Atlantic region is the same old arctic clipper of the past. It occurs when the polar vortex weakens and escaping cold air is funneled south by the jet stream, one of many high speed rivers of air which envelopes the Earth.
Tuesday the arctic clipper arrived from the west with snow, a different weather pattern from the storms which have usually brought large snowstorms in recent decades. Those were coastal storms, bringing moisture from the south which merged with cold air from the north to create wet, sticky snow.
Since it’s so cold in places that are usually quite warm, isn’t that proof there is no such thing as global warming?
For many years scientists have explained that climate change is a symptom of global warming, caused by shifts in weather patterns due to warmer temperatures in arctic regions.
Although scientists have yet to firmly link a weakened polar vortex to global warming, the explanation for why it happens suggests warm air is to blame.
“Today” show weatherman Al Roker recently responded to Limbaugh’s suggestion that the polar vortex is a hoax by pointing to the definition of the term in his 1959 copy of the American Meteorological Society’s glossary of weather terms.
The definition also offers some explanation of what the polar vortex is: “The large-scale cyclonic circulation in the middle and upper troposphere centered generally in the polar regions. Specifically, the vortex has two centers in the mean, one near Baffin Island and another over northeast Siberia. The associated cyclonic wind system comprises the westerlies of middle latitudes.”
The polar vortex is made up of circular winds which surround both of the Earth’s poles. During the winter months, when there is little to no sunlight at the North Pole, the circular winds are usually strong enough to keep the polar air contained to the polar region.
It is when the circular winds of the polar vortex weaken, which scientists say could be caused by warmer temperatures, that the frigid air escapes and merges with the jet stream.
The current dip from the polar vortex is over our part of the Earth. In case you may not have noticed, last year the polar vortex dip reached down to Great Britain, giving that part of the world its coldest March in 50 years, according to information from CNN’s website.
Whether you call it the polar vortex or the arctic clipper, it isn’t going away anytime soon, according to forecasters at Accuweather.com, who have issued the following warning about the polar vortex for the last two weeks of January:
“The high amplitude pattern is forecast to get more extreme. The polar vortex will move farther south and get stronger. The pattern will gradually change the current mixture of Pacific and Arctic air in the Canada Prairies and the North Central U.S. to all Arctic air. The air will get significantly colder over the Canada Prairies and the much of the eastern half of the nation as a result.”
Accuweather.com meteorolgist Alex Sosnowski concludes his warning with what he suggests is the comforting message that despite the forecast for long-term frigid weather, each day of winter brings a little extra warming sunlight to this part of the Earth.
“However,” Sosnowski points out after his meager words of comfort, “the few extra minutes of daylight will have minimal effect on the air mass that could rival the early January visit from the polar vortex.”