The Polar Vortex and What it Means for Us
No doubt you've heard of the Polar Vortex. Contrary to what many think, it's nothing new. It's not a winter hurricane, it doesn't "hit" anything and it's not an alien invasion. It's actually a term that's been used in the weather world for more than 60 years.
So what exactly is it? It's a swirling area of high altitude low pressure with very cold air that sits over the north and south pole. Normally the polar vortex has very strong winds circulating around it which keeps the frigid air confined to areas near the north pole.
Once every year or two, certain atmospheric events lead to the polar vortex being displaced or splitting into pieces. As strange as it may sound, a weaker, displaced or fractured polar vortex can actually lead to rounds of arctic air at the surface plunging into Russia, Europe, Canada and the United States.
Early in January, the polar vortex weakened and broke into three pieces. Where these lobes of low-pressure settle will determine the flow of the jet stream and where the cold air settles. This pattern can be highly amplified (wavy) leading to persistent cold for weeks.
What we don't know now is how global pressure and wind patterns will influence the final resting place for these lobes of low pressure. It takes time for all the moving parts to get into position.
For now, many of the long-range models indicate odds are rising the pattern will turn much colder for the central and eastern U.S. from next weekend into February.
If this pattern does develop as the models suggest, here's what it means for us.
TEMPERATURES - Very likely to be below normal (normals right now are 55/35), but it's way too far out to know how intense the cold would be.
SNOW - The overall pattern would support storms capable of producing snow for the southeast but it doesn't guarantee it. Many times these cold patterns suppress storms well to our south and we stay dry and cold. Let's face it. Even in cold patterns like this, it's difficult to get snow in our area.
Bottom-line, if you like cold temperatures and higher odds of snow, things are looking up for you, but it's no slam dunk.
The Map - GFS Ensemble forecast for temperatures over the next 15 days. Yellows, oranges and reds indicate temperatures above normal. Blues, greens and purples indicate temperatures below normal.