Peoria, Ill. (WMBD) — On Thursday, October 19th, NOAA (National Oceanic and Atmospheric Administration) released their 2023-2024 U.S. winter outlook. The upcoming winter season is expected to be shaped by the strongest El Niño since 2016.
Like all weekly and monthly outlooks, NOAA’s seasonal outlooks are based on probabilities and likelihoods rather than exact forecasts. While they make these forecasts for temperatures and precipitation, they do not make seasonal snowfall predictions.
Temperature Outlook (December, January & February)
Warmer than normal temperatures are favored across the Northern U.S. with the greatest likelihood of above average temperatures overt the Pacific Northwest and northern New England. Meanwhile, near normal temperatures are expected from the high plains of Colorado to northern Texas.
In Central Illinois, their outlook gives the area a 33-40% probability of above average temperatures between December and February. This means the forecasts is leaning towards above average temperatures for the upcoming winter season.
Precipitation Outlook (December, January & February)
Wetter conditions are favored across the southern U.S., most likely over the southeast, while below average precipitation is favored across the north. For areas in between, including Central Illinois, there is an equal chance (33.3%) of near, below or above average precipitation.
Historical Snowfall Trends During El Niño
NOAA does not make seasonal snowfall predictions as snowfall amounts are not predictable more than a week in advance. That said, we can look back at how previous El Niño winters fared when it came to snowfall to get an idea of what may happen.
When we break down El Niño by strength, we find that stronger El Niño events tend to bring less snow to the Midwest while weaker events bring more.
The El Niño Effect
In a news release about NOAA’s winter outlook, Jon Gottschalck, chief of the Operational Prediction Branch of the Climate Prediction Center, stated “An enhanced southern jet stream and associated moisture often present during strong El Nino events supports high odds for above-average precipitation for the Gulf Coast, lower Mississippi Valley and Southeast states this winter.”
A few weeks ago I wrote about how previous winters fared during strong El Niño events. While there have been some exceptions, more often than not these winters were warmer/drier in the north and cooler/wetter in the south and that appears to be the case again this winter. When looking back at past events, Central Illinois tends to experience colder and snowier winters during weaker El Niño events, but that is not expected this year.