What will winter look like? How climate models help us know what to expect

SOUTH BEND, Ind-- The NWS has issued the Seasonal Precipitation Outlook from November to January. Michiana along with other Midwest states are projected to receive above normal precipitation. However, many wonder how these predictions are actually determined?

Professor Michael Morgan from the University of Wisconsin-Madison explains that long range forecasts are determined by “looking at deviations from climatology [and] looking at any anomalous weather patterns that have developed over the United States, but even more broadly around the globe.”

The weather patterns Morgan is describing are the El Nino and La Nina Southern Oscillations—patterns of sea surface temperatures that span from the Central Pacific to South and Central America.

The United States is now under the influence of the La Nina pattern, where sea surface temperatures are cooler than average. Observing weather patterns and dynamic long-term models helps the National Weather Service produce these forecasts.

However, things can get difficult, Morgan says. With above average seasonal temperature and precipitation outlooks, what does that mean for snowfall?

Morgan says, “The possibility of a snowy winter is certainly there.” He continues, “But that compounded with the fact that temperatures are expected to be above normal, probably means it's going to be tricky.” A “cold air outbreak” could be enough to dump a generous amount of snow in a short period of time, making a month or season snowier than normal.

This testament was proven true about a week ago, when temperatures quickly fell to the 30s and Lake Effect Snow impacted much of Michiana. This winter storm began as low pressure moved through, not only bringing system snow but also changing the wind direction—providing more of a Northerly direction. This turned on the Lake Effect snow machine, allowing snow bands to dump several inches of snow in the days following. On the 9th, South Bend received record-breaking snowfall for the day—8.2 inches of snowfall. That record was previously held back in 1913. On the 10th, an addition 6.1 inches of snow fell. 

This is likely a preview of how winter will be this season—colder and snowier than years prior. For a more in-depth look at the winter forecast, check out ABC 57 First Warning Neighborhood Weather Winter Knockout on ABC57.com, to see whether warm or cold air will dominate this winter.