There are indeed signs that a circular low-pressure system of swirling winds that normally keeps frigid air locked up at the North Pole has been disrupted and split into smaller parts.
The disruption in this counterclockwise-spinning beast, called the polar vortex, is thought to be caused in part by a warm summer over the Arctic and a relatively cold fall over Siberia.
I wrote in the December 21, 2020 blog our #PolarVortex (PV) model is predicting a major sudden stratospheric warming in early January and then again third week of January. Based on latest model forecasts there really does seem to be two distinct polar warming events in January. pic.twitter.com/vcMCPztoAh— Judah Cohen (@judah47) January 8, 2021
The result for the United States and northern Europe?
A severe winter lasting throughout February and possibly into March.
The breaking up of the polar vortex could be the culprit for the coming extreme storms.
A lot of #PolarVortex chatter. Normally it stays north, but it’s splitting due to big warm up in the North Pole & could be heading south. Indications are that we could see a big blast of cold…or coldest air yet…by the 16th of Jan and the 19th. Models a bit back & forth tho. pic.twitter.com/Jr4q0tv4vn— Brian Smith WTVC (@StormTrackBrian) January 8, 2021
The weather models suggest that the disruptions would follow the pattern of polar vortex collapses seen during the northern winter last year, which resulted in freezing weather across the United States in December and January, and a severe cold snap in March over the United Kingdom.
“This pattern looks much more active, [with] more winter type storms and Arctic outbreaks — I think I would attribute it to definitely being a polar vortex disruption, because it is very consistent with what we’ve seen in the past.”
The northern polar vortex is a fast-flowing stream of air that circles the North Pole in the upper parts of the atmosphere, known as the stratosphere, about 20 miles (32 kilometers) above the surface.
A similar polar vortex exists over the South Pole, but it is the northern polar vortex that can bring severe winter weather to the United States and Europe.
When the northern polar vortex is strong, it keeps most of the air cooled by the Arctic in the polar region, resulting in mild winter temperatures in the middle latitudes of the eastern United States, and in northern Europe and Asia.
But when the polar vortex weakens, the once-trapped cold air can meander throughout the top of the Northern Hemisphere, bringing polar temperatures and extreme winter weather to lower latitudes.
“Think of the polar vortex as a spinning top, and where the polar vortex goes so goes the cold air. A strong polar vortex is a fast, tightly spinning top centered over the North Pole, keeping all the cold air with it close by over the Arctic. [But] a weak or perturbed polar vortex is a spinning top that has been banged or bumped into an object multiple times … the top slows down and wobbles and can meander from its location.“
A dramatic spike in temperatures – sudden stratospheric warming event – is currently occurring at high altitudes above the North Pole, where the air is thin and typically frigid.
Experts say it’s likely to have potentially significant repercussions for winter weather across the Northern Hemisphere for weeks to possibly months, possibly increasing the potential for paralyzing snowstorms and punishing blasts of Arctic air, with the odds of the most severe cold outbreaks highest in Northern Europe.
Colleagues in East Asia are telling me of anomalous cold currently, thanks to Ural ridging. That is now predicted to fade coincident with #polarvortex disruption and to be replaced with troughing and much #colder temperatures across the Urals and possibly into Northern Europe. pic.twitter.com/5SZe2aIJlZ— Judah Cohen (@judah47) January 7, 2021
Such extreme stratospheric warming events can affect the polar vortex, which is a circulation of air around low pressure that acts as a repository for some of the coldest air on the planet.
And that’s exactly what’s begun to happen. Due in large part to this stratospheric temperature spike, the polar vortex has started weakening and wobbling off the pole, splitting in two.
So be ready, winter 2021 will be terrible and may lead again to catastrophic flooding along the Missouri River Basin. You remember?