Winter weather is starting to make headlines across the United States. Searches for "polar vortex November 2026" and the "Climate Prediction Center heavy snow map" jumped this week after forecasters flagged a rare early disruption of the polar vortex and a moderate risk of heavy snow in the West.
Here's what the polar vortex is, what the latest NOAA maps show, and what it could mean for your weather later this month and into December.
What Is the Polar Vortex?
The polar vortex is a band of strong westerly winds about 10 to 30 miles above the North Pole, in a layer of the atmosphere called the stratosphere. In winter, it normally works like a fence, keeping the coldest air locked near the Arctic.
When the vortex weakens or gets disrupted, that cold Arctic air can break away and move south into North America, Europe or Asia. According to NOAA, in some cases it can push cold air as far south as Florida.
The Rare November Disruption
The NWS Climate Prediction Center (CPC) said forecast models "indicate the potential for a stratospheric polar vortex disruption." That could develop into a sudden stratospheric warming (SSW), which the CPC called "very rare" for November.
- What happens: During an SSW, the air high above the Arctic heats up quickly, sometimes by 40 to 50 degrees Celsius within days, and the polar winds weaken or even reverse.
- The data: According to The Watchers, polar vortex winds at 60 degrees north dropped from about 22 to about 5 meters per second in eight days.
- How long it lasts: Effects of an SSW can last up to two months.
When Could the Cold Arrive?
The impacts are not immediate. Surface weather usually changes weeks after a stratospheric disruption, so late November and December are the periods to watch.
The CPC said there is "some potential for troughing to settle over the Southeast by the end of the month," which could bring cooler conditions to parts of the Southeast. But forecasters stress that the exact placement and strength of any cold pattern remain uncertain.
Important: A polar vortex disruption does not guarantee a major cold snap or a widespread Arctic outbreak. It increases the chances, but it is not a certainty.
CPC Heavy Snow Map: November 13-15
Separately, the CPC's week-two hazards outlook, released November 5, shows a moderate risk of heavy snow from Friday, November 13, through Sunday, November 15.
- Where: The mountains of southern Oregon and California's Sierra Nevada and Klamath Mountains.
- Rain at lower elevations: Snow levels are expected to stay high, so most precipitation at lower elevations should fall as rain.
- Heavy precipitation: Extends north into Washington.
- High winds: A moderate risk along the coasts of Washington, Oregon and California from November 13 to 15.
- More mountain snow: A slight risk of heavy high-elevation snow through November 17 for the Cascades, the Central and Northern Rockies and parts of the Great Basin.
According to Autoblog, CPC forecaster Thomas Collow said the chance of three-day snow totals topping six inches had declined since the previous outlook.
Travel Impact
Drivers heading over the Sierra should be ready. Interstate 80 over Donner Summit and U.S. 50 over Echo Summit are in the heavy snow zone, so chain controls are likely near the summits from November 13 to 15. Check Caltrans road conditions before you leave and carry chains.
What About the Rest of the Country?
For now, most of the Lower 48 leans warmer than normal. Parts of the Middle Mississippi Valley, Ohio Valley and Mid-Atlantic may see near-freezing nights, but first freezes are running two to three weeks later than usual in some areas.
El Niño and the Winter Forecast
The bigger winter picture is shaped by El Niño. The CPC expects El Niño to remain the dominant climate influence this winter. In a typical El Niño winter, the southern U.S. tends to be wetter and the northern tier milder than normal. The polar vortex disruption is the wild card that could upend that pattern, especially in the eastern U.S.
How to Prepare for a Cold Snap
- Check your heating system and replace furnace filters.
- Protect pipes by insulating those in unheated spaces.
- Build a winter car kit with blankets, a flashlight, an ice scraper and snacks.
- Follow local forecasts from the National Weather Service for updates.
Frequently Asked Questions
Is a polar vortex coming in November 2026?
Forecasters are watching a rare early disruption. Any cold impacts would most likely arrive in late November or December, but a major cold snap is not guaranteed.
Where will it snow heavily next week?
The CPC shows a moderate risk of heavy snow in southern Oregon and California's Sierra Nevada and Klamath Mountains from November 13 to 15.
What is a sudden stratospheric warming?
A rapid warming of the air high above the Arctic that weakens the polar vortex and can send cold air south weeks later.