Polar Vortex

High in the atmosphere above the North Pole, a spike in temperatures may soon send bone-rattling chills spilling down through the Northern Hemisphere.

The icy blasts threatening to sweep across North America, Europe and Asia starting in late January are from the same weather pattern that triggered the 2014 cold snap known as the polar vortex, which plunged temperatures in Chicago to minus -16° Fahrenheit (-27° C).

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It’s common during winter for frigid air to roar down from the Arctic. But the cold mostly stayed bottled up around the North Pole in the season of 2019-2020. Now, after a nearly two-year hiatus, winter is threatening to return at last.

Florida January 2014

Forecasters aren’t expecting the cold to be as brutal as during the 2014 polar vortex, which was an extreme example of Arctic weather plunging south. But it will feel unmistakably like winter. In 2014 the cold air moderated as it reached the Florida peninsula, but still caused a very rare freeze in Tampa on January 7, 2014, when the city had a low of 31°.

The cold has already descended upon Western Europe and China, sending prices for gas in Spain, and liquefied natural gas in Asia, to record highs. Paris has been 3.5° below normal and Madrid 6.9° cooler, while Beijing temperatures fell to a record low of -9 this week.

The vortex of seven years ago kept shoppers indoors, grounded flights and made it harder for shippers to fill product orders. This year, the pandemic has already hobbled travel and in-store shopping. Snowstorms, however, could be a nightmare for delivery services.

"Polar Pig": Polar Vortex Defined

NOAA defines the polar vortex as a large area of low pressure and cold air surrounding both of the Earth’s poles. It ALWAYS exists near the poles, but weakens in summer and strengthens in winter. The term "vortex" refers to the counter-clockwise flow of air that helps keep the colder air near the Poles. Many times during winter in the northern hemisphere, the polar vortex will expand, sending cold air southward with the jet stream (see graphic below). This occurs fairly regularly during wintertime and is often associated with large outbreaks of Arctic air in the United States. The one that occurred January 2014 is similar to many other cold outbreaks that have occurred in the past, including several notable colder outbreaks in 1977, 1982, 1985 and 1989.

Florida 1989 Freeze

December of 1989 featured several surges of Arctic air into the central and eastern United States beginning around mid month and lasting until Christmas. This Arctic outbreak was a historic event, with many locations establishing monthly or all-time record lows. Sub-freezing temperatures extended across much of the southeast U.S. with considerable damage to citrus crops in Florida and south Texas (newspaper reports indicated "nearly total destruction" of the citrus industry across the north half of Florida).

Snow fell across the I-4 corridor Dec. 22-24, 1989.

This freeze occurred on December 22-26. This freeze was the fifth impact freeze recorded in Florida history, however it was the second impact freeze in a single decade. "Impact" in this context meaning the freeze had a massive impact on Florida citrus growers leaving growers little time to recover after the freezes of 1983 and 1985.

Newscasters often refer to the polar vortex as to a band of winds that encircle the Arctic and keep the cold locked far to the North. They often add that a temperature spike in the Arctic accompanies outbreaks in the cold outbreaks over the Northern Hemisphere continents. That temperature spike, known as sudden stratospheric warming, can cause the band of wind to buckle, allowing frigid air to head south.

Gas traders used to call it the “polar pig.”

Climate Change Might Be Driving Historic Cold Snaps

That could mean chills anywhere in the Northern Hemisphere, though this year it’s likely to end up in the U.S. according to Ryan Truchelut, president of Weather Tiger LCC. A wave of deep cold could give the Great Lakes and East Coast their first real blast of frigid winter weather, along with a storm pattern that delivers snow storms as well.

It will be a big shift for the U.S., where winter has been a bit lackluster so far. In New York, January readings have been 5.1° above normal through mid-January, and Chicago has been 7.2° warmer for the month. In Central Florida it has been a cold December and January, so far. But we've escaped widespread below 32° temperatures, for the past 3 years.

1100 Days and Counting since Freezing

Stretch of consecutive days where the minimum temperature has remained above 32 degrees (still ongoing):

Number of Days*/Ranking: Current or Previous Record:

Daytona 1077 (2nd Longest Stretch) 1497 (12/25/1929-01/29/1934)

Leesburg 1078 (Longest Stretch) 729 (01/26/2003-01/23/2005)

Sanford 1077 (2nd Longest Stretch) 1115 (01/25/2003-02/12/2006)

Orlando 1078 (4th Longest Stretch) 1804 (01/25/2003-01/02/2008)

Melbourne 1078 (Tied for 4th Longest) 1538 (01/27/1950-02/11/1955)

Vero Beach 1078 (6th Longest Stretch) 2915 (01/16/1948-01/08/1956)

Ft. Pierce 1078 (3rd Longest Stretch) 1459 (01/20/2014-01/17/2018)

*Note: Current period above freezing began on 1/19/2018 for Leesburg, Orlando, Melbourne, Vero Beach and Ft. Pierce, and 1/20/2018 for Daytona Beach and Sanford. Streak above freezing is still ongoing for all sites, but total number of days reflected above goes through 12/31/2020.

Still, there’s no guarantee it will happen. While a sudden stratospheric warming usually leads to a burst of frigid weather, sometimes the clockwork of gears in the atmosphere doesn’t deliver. So lets hope the current forecasts are only a false alarm.

Red line over Florida indicates forecast freezing line at 850 hPa (altitude of ~1.5 km) on Jan. 27, 2021

What the Polar Vortex is NOT

There are several things the polar vortex is NOT. Polar vortexes are not something new. The term “polar vortex” has only recently been popularized, bringing attention to a weather feature that has always been present. It is also not a feature that exists at the Earth’s surface. Weather forecasters examine the polar vortex by looking at conditions tens of thousands of feet up in the atmosphere; however, when we feel extremely cold air from the Arctic regions at Earth’s surface, it is sometimes associated with the polar vortex. This is not confined to the United States. Portions of Europe and Asia also experience cold surges connected to the polar vortex. By itself, the only danger to humans is the magnitude of how cold temperatures will get when the polar vortex expands, sending Arctic air southward into areas that are not typically that cold.