The high school dropout ruining Environment and bulk deleting posts and threads mentioned Arctic Blast. Of course, he had no idea what caused it. Let us have a look, eh?


Quote:

What’s Behind the ‘Arctic Blast’ Plunging into the U.S.? This week’s cold snap across the U.S. will be one of “the most impressive Arctic outbreaks of this century,” one climate scientist says. . .“It will be a very impressive—certainly one of the most impressive Arctic outbreaks of this century anyway,” says Judah Cohen, a climate scientist at the company Verisk Atmospheric and Environmental Research. Similar recent events have included the terrible cold snap that struck Texas in February 2021 and a sharp preholiday freeze in December 2022, Cohen notes. Fortunately, this Arctic blast isn’t expected to be as deadly as the Texas event. . . Meanwhile here’s the science behind why temperatures are suddenly plummeting so sharply across such a wide swath of North America. Typically, very cold air in the Arctic is trapped inside a high-altitude swirl of winds called the polar vortex, which is surrounded by a lower-altitude band called the polar jet stream. If the polar vortex gets disrupted, however, the jet stream can become wavy and carry frigid air much farther south than usual in an Arctic blast. Sometimes this frigid air brings snow and ice; other times the weather is dry but bitterly cold. Still, many experts believe climate change likely plays a role—and Cohen goes even further: he contends that climate change in the Arctic is directly disrupting the polar vortex. According to Cohen, this winter’s melting sea ice near Scandinavia coupled with high snowfall near Siberia to set up a thermal contrast, which he says drove the polar jet stream into waves. The polar vortex typically “wakes up” around January, he adds, so it makes sense that we’re now feeling the sharp chill from an Arctic blast whose stage was set by these distant trends. “It seems very counterintuitive and surprising that a warmer planet can actually increase your odds of experiencing severe winter weather events—but that’s what our research has shown,” Cohen says.

https://www.scientificamerican.com/article/whats-behind-the-arctic-blast-plunging-into-the-u-s/

Over the tropics warm air expands so the troposphere rises. Over the poles the air is colder and denser. When winter hits one of the poles the air contracts even more. Tropical air moves “down the slope” towards that pole. The earths rotation causes the descending air to rotate—the polar vortex. That vortex can wobble.

Jet streams are involved too—they are weak and wavy due AGW.

Jet streams were weak and wobbly back when it was cold—it is the equalisation of temperatures that causes them to weaken.