What’s the difference between the polar vortex and a low pressure system?
Bastardi has been touting a cold Jan to March for some time. Says it is not a polar vortex just a normal situation due to the weather systems set up.
There are two important scientific principles we learned in school: The earth rotates once a day, and warm air rises (with the associated fact that cold air falls). The warm air at the equator is mostly moving at about 1000 mph, the speed of the earth's surface there. As this warm air rises and cools, it doesn't completely stop moving before it gets to the poles which aren't moving at all, they just swivel about, once a day. This means that the cold air falling at the poles is still spinning a bit as it falls. It's this spinning air at the poles that has been given the scary name: "Polar Vortex".
The air doesn't actually just rise at the equator, and fall at the poles. There are some complicated twists and turns along the way. These twists and turns give rise to jet streams, high pressure systems, and low pressure systems, and other things that we call "weather". A significant driving force in weather, though is this changing speed of the earth's surface between the equator and the poles, and the rise and fall of air because of temperature differences. Air isn't totally well behaved, either. It gets pushed and pulled about due to these competing forces, and the Polar Vortex doesn't always stay centered over the poles. It's been described as a yarmulke thats not pinned down properly. It can slide about on your head, but rarely comes down to cover your nose. When it hits your city, though, you can count of the fact that Global Warming will be blamed.