Weather for the Week of 1/19/14, and Polar Vortices
The really, really cold weather is back. The above map shows the low temperatures on Tuesday night, which will be the coldest of the week. Bottoms out at -5, and it will be a few degrees colder here in Manchester.
The real story is the wind chill. There won’t be a lot of wind, but what wind there is will get as cold as 25 below zero. That can cause frostbite after five minutes, and can be very dangerous to pets. Be careful.
Apart from nasty cold, the rest of the weather is pretty nice. Sunny on and off, and just a little snow to make things look pretty. Accumulations will be less than a half inch.
The cold weather this week is caused by the polar vortex, just as the weather earlier in the month was. So what is the polar vortex?
Both the north and south pole have a large, swirling mass of super-cold air over them. This is the polar vortex. It varies in size and temperature throughout the year, but it’s always there.
Usually other forces in our atmosphere keep the polar vortex over the poles where it’s cold anyway. But when some of those forces are weak or absent, it leaks down into places that don’t usually have wind chill values at twenty and twenty five below. Like Manchester.
There is an excellent graphic about it from the National Weather Service about it. Click here if you are interested.