Weeks after The Vane coined the defining term of summer 2014 — SummerPolarVortexmageddon — another huge cool-down is on tap for next week, and everyone is hopping on the "polar vortex" bandwagon. Imitation is the sincerest form of flattery.
A true polar vortex is essentially a big low pressure center that sits over the North Pole. Every once and a while, it will sort of break apart and turn into a group of smaller low pressure systems circling around the northern hemisphere. When one of these smaller low pressure centers — the "polar vortex" — spins over North America, it can bring exceptionally cold air to its victims and make everyone with an internet connection panic like cavemen seeing a comet for the first time.
What will happen next week is not a polar vortex. At best it's a Hudson Vortex. Manitobavex. But it is not a true polar vortex.
Here's the setup:
This chart shows the 500 millibar pressure level of the atmosphere, or the pressure and wind between 18,000 and 20,000 feet above ground level. Last night's run of the ECMWF (European model) shows a large low height center (essentially a low pressure center) forming over Northern Manitoba before growing quite large and moving towards the Great Lakes.
This Canadian Hudsontobavex(mageddon) will drag down much cooler air into the United States thanks to its northerly winds.
Both the GFS (American) and ECMWF (European) models agree that the end result will bring temperatures of 10 to 20 or more degrees below average for this time of year.
In the best case scenario, the European model even suggests that the Canadian Hudsontobavex(...mageddon) could reach as far south as Dallas, Little Rock, Huntsville, and Charlotte by late next week.
Happy summer! Enjoy the cool temperatures and even cooler media hype.
[Top image The Day After Tomorrow, all model images via WeatherBELL]