The latest outlook for the winter season from the Climate Prediction Center highlights a forecast that snow lovers may not be too happy about across the Midwest and Great Lakes. El Niño conditions have developed and are forecast to strengthen over the next couple of months.
The official outlook highlights a higher probability for above average temperatures over much of the country, with near normal temperatures for parts of the Rockies and Plains.
A higher probability for above average precipitation is forecast in the south, while drier conditions are possible across the High Plains, northern Rockies, and Great Lakes. Both of these outlooks are very similar to what a typical winter pattern looks like during an El Niño season.
El Niño is the warming of sea surface temperatures within a certain region across the equatorial Pacific over a duration of time. La Niña is the opposite: cooling sea surface temperatures within that same region.
According to the Climate Prediction Center, while a slight decrease in the warming trend occurred earlier in September the overall forecast and trends are consistent with El Niño conditions to continue, and strengthen, through the winter season. It’s also likely these conditions will persist through spring in the Northern Hemisphere.
So, what could this mean for the winter season here in the Stateline? If we look back at the past strong El Niño winter events, 1982-1983, 1997-1998, and 2014-2016, we may get a little bit of an idea of what this upcoming winter season could bring.
The winter season is climatologically defined as the three-month period of December, January, and February. During the first two months of those strong El Niño years, the monthly temperature ended up slightly above average, while snowfall fell below the monthly average. We made up for the lack of snow a little bit during the month of February, but both February snowfall and temperatures varied from year to year.
Typically, during an El Niño winter season temperatures are warmer than normal, and precipitation (which also includes snowfall) ends up falling below average. But other atmospheric patterns and circulations can play a role in the overall weather pattern across the United States, despite a strong or weak El Niño. All it takes is one or two big snow events to push snowfall totals up closer to the seasonal average, which is 37 inches. And even though the average three-month temperature may end up on the warmer side, there will still be below average, and well below average, days.