What a Historic Polar Vortex Disruption Means for Your Winter Forecast
The polar vortex set a new record for the earliest disruption ever. But what does that mean for the upcoming winter weather? Here is what you need to know as winter approaches.
Meteorologists Note Early Polar Vortex Disruption
According to new data revealed last week, the polar vortex has been disrupted from its typical position at the earliest point in a calendar year. This band of powerful winds circulating over the North Pole influences the weather in the U.S. and Canada. Normal seasonal weather patterns in the Earth's lower atmosphere often send waves high into the stratosphere, disrupting the vortex's position and strength.
In short, a strong and stable polar vortex keeps the coldest air on the planet locked up at the North Pole. Conversely, the disruption of the vortex can release the Arctic air that circulates in this part of the world. The frigid air that escapes is able to creep down into Canada and the northern U.S., triggering sharp temperature drops.
However, just because this disruption happened at the earliest point ever this year, it does not mean that it is going to be a brutal winter. Forecasters say that the emergence of the Super El Niño may actually mitigate some of the impacts of a weakening polar vortex.
This is largely because temperatures have been trending warmer than historical averages across Canada and the northern U.S. These warmer readings are typical of a Super El Niño year. This means that any air being pushed down from Canada and into the U.S. is not cold enough yet.
In addition, forecasters note that changes in the stratosphere do not immediately translate to colder temperatures at the surface. It can take several weeks for these disruptions to inch down and impact the jet stream and overall weather patterns.
As such, forecasters say that this early breakdown of the polar vortex does not mean that Americans need to be dragging out winter coats and snow shovels quite yet. Any impacts of the recent disruption would not likely affect North America until at least the end of November or early December.
The latest forecast models suggest that the coldest air coming out of the North Pole will end up in Eastern Europe and Siberia. North America will continue to see readings hover above the norm for at least a few more weeks.
How El Niño Will Impact the Months Ahead
El Niño is showing no signs of slowing down. The climate phase continues to strengthen and is expected to drive the weather over the next few months. While it is not quite at the level of a Super El Niño yet, this declaration is predicted to happen by December.
The phase has already begun to deliver a boost to the Pacific jet stream, transporting the mild temperatures from the tropics into parts of the U.S. This jet stream movement is also bringing in more storms from the Pacific at the same time. The pattern is forecast to persist for several weeks, translating to above-average temperatures that will limit the ability of cold air from the north to become entrenched across the U.S.
The National Weather Service (NWS) Climate Prediction Center (CPC) predicts that temperatures will remain above average for a large swath of the northern U.S., stretching from the Pacific Northwest and through the Northern Plains, the Upper Midwest, the Great Lakes, and the Northeast. The CPC forecasts this will be the story through at least December.
That said, you cannot rule out brief intrusions of cold air during this time. Be sure to check back often to see how El Niño and the polar vortex work together to influence the weather on a micro scale.
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