A Congressional Research Service In Focus report explains the Arctic stratospheric polar vortex and the federal role in forecasting its disruptions. The polar vortex is a band of strong winds roughly 10 to 30 miles above the surface that forms each winter; when it weakens, shifts, or splits, the jet stream becomes “wavy” and cold air can move south, producing events colloquially called Arctic blasts. The report cites the February 2021 South-Central US cold outbreak, which contributed to more than $20 billion in economic losses and over 220 fatalities and left nearly 10 million Texans without power. It notes that scientists have observed no long-term trend in polar vortex disruptions, and that models diverge on whether warming and declining sea ice will produce a weaker or stronger vortex. NOAA’s National Weather Service, authorized to forecast weather under 15 U.S.C. §313, can generally predict specific disruptions days to about two weeks in advance, though impacts on US weather can persist for weeks to months. Congress may consider whether to modify the federal role in forecasting and researching such events.
(Congressional Research Service, 2026)
Source: Congressional Research Service · original
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