https://x.com/severeweatherEU/status/2108462156245078159
SWE | severe-weather.eu
@severeweatherEU
Can rapid October snow advance in Siberia predict your winter? This is a famous forecast signal for cold winters in the U.S. and Europe, so we tested it across 47 winters of data and 4 different datasets. The results were surprising, and they change how we should read this October’s snow surge as we head into Winter 2026/2027.
The first week of October was a bit slower than normal. But the forecast shows a big surge of snow coming in the next two weeks. If it verifies, this would be one of the faster October snow advances of the last three decades, roughly in the top 15% for this period of the month.
Keep in mind that this is still an early look, as most of the data comes from the ECMWF forecast, which updates several times per day. The true final number will only be known after October 31.
So, what happened with winter after similar October snow advances in the past? Below are the six years with the most similar October snow advances so far, and the winter AO that followed.
The following winter AO was negative three times, near neutral once, and positive twice. Three of these years, 2002, 2019, and 2023, also had active El Niño, like this year, but they still produced three very different winters. So on its own, a fast snow advance this October tells us little about the coming winter in the modern era.