As the northeast was mired in frigid temperatures last winter, the term polar vortex was regular dinnertime chatter as it got blamed for burying Boston in more than 100 inches of snow.
But this year the polar vortex is quite strong, yet there’s nary a peep about it’s influence on the weather, noted J. Marshall Shepherd, director of the atmospheric sciences program at the University of Georgia.
Shepherd is also host of the Weather Channel’s “Weather Geeks” show.
It’s turns out this year’s brawny polar vortex – a swirling mass of cold air over the arctic – can actually be linked to the crazy-warm temperatures throughout the eastern U.S.
Palm Beach County heat record could be tied today. Read why here.
A stronger, or more stable, vortex is less likely to release frigid polar air, which then cascades south through Canada and into the U.S. The jet stream, which wraps around the globe in a circular pattern, also plays a role. When it weakens, it becomes wavy, again allowing cold air to punch south.
“When the polar vortex is strong, Arctic air cannot escape the ‘fence’ and ooze its way down into the United States,” Shepherd wrote on his Forbes science blog. “I say ‘ooze’ because cold air is dense relative to warm air. If the Polar Vortex weakens, the cold air can more easily penetrate into the lower 48 states.”
In a YouTube explanation posted on a White House blog last year, John Holdren, director of the White House Office of Science and Technology, explains in about two minutes what the polar vortex is and how it relates to climate change.
AccuWeather senior meteorologist Alex Sosnowski writes that El Nino’s strong westerly winds may be helping keep the polar vortex contained up north. When El Nino dissipates, which it’s not supposed to do until spring at least, fluctuating steering winds “may allow the polar vortex to weaken, shift position and send frigid air well to the south.”