The Polar Vortex: Background and Forecasting

February 6, 2026

The Polar Vortex: Background and Forecasting

In recent years, broadcast meteorologists and the media

have begun using the term polar vortex to describe some

instances of unseasonable temperatures and storms across

the United States during the winter months. The polar

vortex is a regular seasonal occurrence, and disruptions to it

can cause both milder- and colder-than-average

temperatures across North America. For example, in

February 2021, the South-Central United States

experienced an influx of record-breaking cold air from the

north with accompanying snow and ice (Figure 1),

contributing to over $20 billion in economic losses and

more than 220 fatalities. During that event, multiple sectors

experienced damage and losses, including agriculture and

water and electric utilities, resulting in nearly 10 million

Texans without power at one point. Congress has shown

interest in protecting life and property from extreme

weather events associated with disruptions to the polar

vortex and may consider whether to modify the federal

government’s role in forecasting and researching such

events.

Figure 1. Mean Temperature Departures from

Average, February 7-21, 2021

Average Period: 1981-2010

Arctic blasts or cold air outbreaks. The polar vortex and jet

stream are two of several simultaneous global atmospheric

patterns created by the interaction of the Earth, its tilt, and

the sun’s rays. Scientists have not observed a long-term

trend or pattern in disruptions to the polar vortex. Some

models predict that increased warming and reductions in

sea ice cover will produce a weaker polar vortex; others

predict a stronger polar vortex.

Forecasting

Congress has authorized the Secretary of Commerce, acting

through the National Oceanic and Atmospheric

Administration’s (NOAA’s) Administrator, to forecast

weather and issue storm warnings (15 U.S.C. §313 and

§313 notes). NOAA National Weather Service (NWS)

forecasters examine atmospheric conditions at the North

Pole and forecast changes to the polar vortex. Forecasters

generally are able to predict specific disruptions to the polar

vortex a few days to about two weeks ahead of time; the

disruption’s associated impacts on U.S. weather can last for

weeks to months. NOAA forecasters issue watches and

warnings for hazards associated with these disruptions, such

as extreme cold, freezes, frosts, blizzards, winter storms

(snow, ice, sleet, or blowing snow), and ice storms.

Forecasters provide their predictions and other services to

various stakeholders, such as emergency managers,

government partners, members of the media, and the public,

to help with preparedness and response efforts.

Research

Source: National Oceanic and Atmospheric Administration,

National Centers for Environmental Information, “Monthly Climate

Reports – Synoptic Discussion February 2021.”

The Arctic stratospheric polar vortex (hereinafter polar

vortex) is a strong band of winds about 10 to 30 miles

above the Earth’s surface that forms every winter. In typical

years, a stable polar vortex and the polar jet stream

(another band of strong winds, hereinafter jet stream) work

together to contain cold air at higher latitudes (Figure 2).

Every so often, the polar vortex weakens, shifts, or splits

into multiple vortices. When this occurs, the jet stream

becomes “wavy” and cold air moves south and warm air

moves north, producing a disrupted polar vortex.

Meteorologists sometimes identify these cold air pulses as

Congress has directed NOAA and other federal agencies

(e.g., National Science Foundation, National Aeronautics

and Space Administration) to perform and support research

that could address some outstanding research questions.

These include the relationships between the polar vortex,

other parts of the atmosphere, other global atmospheric

patterns, and environmental conditions (e.g., surface

temperature and pressure, sea ice cover), as well as the

impact of climate change on those patterns and conditions.

NOAA historically has funded research at its laboratories

and cooperative institutes, such as the Pacific Marine

Environmental Laboratory and the Cooperative Institute for

Climate, Ocean, and Ecosystem Studies, as well as through

competitive grants from NOAA’s Office of Oceanic and

Atmospheric Research (OAR).

Considerations for Congress

The Trump Administration has taken steps to change

NOAA’s implementation and support of forecasting and

research; Congress may consider whether to take additional

steps to codify, modify, or reverse the Administration’s

actions. The Administration’s actions include pausing

disbursement of NOAA funds appropriated through P.L.

117-169, commonly referred to as the Inflation Reduction

https://crsreports.congress.gov

The Polar Vortex: Background and Forecasting

Act of 2022 (IRA), in January 2025 and proposing to

eliminate funding for some programs (e.g., climate labs and

cooperative institutes, climate competitive research) and to

dissolve OAR in FY2026. In July 2025, Congress rescinded

unobligated balances of IRA funding for NOAA (P.L. 11921 §40008). CRS was unable to identify how the

Administration’s pause and congressional rescission of IRA

funds may have specifically impacted NOAA’s weather and

climate forecasting and research efforts. In January 2026,

Congress supported “full staffing levels at all Weather

Forecast Offices,” provided funding for weather and

climate forecasting and research, and retained OAR, as

described in the explanatory statement accompanying the

FY2026 NOAA appropriations law (P.L. 119-74).

Some may assert that Congress should put greater emphasis

on forecasting and researching the impacts of polar vortex

disruptions. Congress could do so by directing NOAA to

focus on the phenomena in existing programs or create a

new standalone program for certain weather events, such as

the hurricane forecast improvement program (15 U.S.C.

§8514). Others may note that disruptions to the polar vortex

and their impacts are already part of NOAA’s weather

forecasting activities or that extreme events are rare and do

not warrant additional attention.

Others may emphasize to Congress that a greater

understanding of the relationships between atmospheric and

other environmental components broadly could increase the

lead time and accuracy of forecasts of both disruptions to

the polar vortex and the resulting extreme winter weather,

among other phenomena. Improved forecasts could further

protect life and property. The 119th Congress is considering

directing NOAA to improve weather forecasting broadly

across multiple components and timescales (e.g., H.R.

5089, see CRS In Focus IF12698, Weather Act

Reauthorization Act of 2025 (H.R. 3816 and H.R. 5089))

and may deliberate additional directives.

Congress also could address aspects of polar vortex-related

weather forecast communication. For example, scientists

have found that the term polar vortex is used by the media

but that the “use of the term without adequate explanation

can suggest a more dramatic change to the global

[atmospheric] circulation than has actually occurred.” Poor

use of the term may cause unnecessary public alarm or,

alternatively, may put life and property at risk if the public

and emergency managers misunderstand the potential

severity of an event. Congress has previously required

NOAA to assess and recommend improvements to the

communication of hazardous weather events (P.L. 115-25,

§406). NOAA continues to update its hazard

communications (e.g., cold weather products) and to fund

social science research as it relates to improving weather

forecast understanding and response (e.g., FY2025 funded

projects). Given how the term polar vortex is sometimes

misused, Congress could direct or encourage NOAA to

improve its polar vortex-related weather forecast

communication and/or to provide training to its partners,

among other actions, to further protect life and property.

Figure 2. Schematic of Stable vs. Disrupted Artic Polar Vortex

Source: Rebecca Lindsey, “Understanding the Arctic Polar Vortex,” Climate.gov, March 5, 2021.

IF13164

Eva Lipiec, Specialist in Natural Resource Policy

https://crsreports.congress.gov

The Polar Vortex: Background and Forecasting

Disclaimer

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