@optilacrity: What makes this winter particularly interesting There are really two major things happening at once: 1. The polar vortex is starting relatively strong. Recent analyses show the vortex strengthening over the Arctic as expected during September, with indications that it is stronger than average for this point in the season. A strong, intact vortex usually keeps the coldest Arctic air bottled up farther north. So paradoxically, a strong polar vortex can mean fewer major Arctic outbreaks into the central/eastern United States. 2. A potentially extraordinary El Niño is developing. This part is especially noteworthy. NOAA currently says there is greater than a 90% chance of a very strong El Niño this fall and winter, and its September update puts the chance of an event exceeding previous El Niños in its record at 75% for October–December 2026 by its RONI measure. NOAA’s experimental SPEAR model also continues to show an El Niño capable of competing with the strongest events in the historical record. The potential twist: January and February This is where the polar vortex becomes important. El Niño can alter large atmospheric waves traveling from the lower atmosphere into the stratosphere. Under the right circumstances, those waves can disturb the polar vortex. In an extreme case, you get a Sudden Stratospheric Warming (SSW). Temperatures high above the Arctic rise dramatically, the stratospheric winds weaken or reverse, and the vortex can become displaced or even split. If that happens, Arctic air becomes much more capable of spilling southward. But there’s an important catch: an SSW doesn’t tell us exactly where the cold will go. Europe could receive the strongest outbreak, or eastern North America, or Asia. And sometimes the surface response isn’t particularly dramatic at all. That’s why a September polar-vortex forecast can’t reliably predict a January cold wave in Missouri. #Science #polar #arctic #winter #cold

The Daily Discovery

Open In TikTok:

Region: US

Sunday 27 September 2026 18:50:40 GMT