Warm temperatures across the northern United States have led to below-normal snowfall across many cities, but Southern states are getting more than their normal share.
For instance, Amarillo, Texas, has had more than 15 inches of snow—surpassing Green Bay, Wisconsin, which has had 11, as well as Chicago and Grand Rapids, Michigan, with about nine inches each.
When calculating snowfall, the 2020-21 Winter Season is defined as July 1, 2020, through June 30, 2021.
San Angelo, Texas, has had 5.8 inches, which is more than Cincinnati (3.1 inches), Indianapolis (5.4 inches), and Louisville, Kentucky (3.5 inches).
Shreveport, Louisiana, has had more than three inches, which is more than Washington, D.C., and St. Louis.
The science behind this shift of snowfall is simple. In addition to the milder temperatures in the northern part of the country, there hasn’t been a big amplified jet stream this year—and both of those factors are limiting snow systems from moving through the region. So we have had a more southerly storm track, which has brought more snow to some Southern locations.
Missing Polar Vortex
Temperatures have been one of the main contributing factors, because without cold air, you can’t have snow.
Since Jan. 1, much of the Midwest and Northeast—including Minneapolis, Chicago, Cleveland, and Buffalo—have had air temperatures at least 5 to 10 degrees above average. This may not sound like a lot, but it is enough to often make the difference between rain and snow.
“In addition, several snow events in Milwaukee this year have featured lower than average snow-to-liquid ratios due to warmer temperatures, so what precipitation has fallen has not produced as much snow as might have otherwise been,” says Andy Boxell, the lead forecaster at the National Weather Service in Milwaukee.
Statistically, January is the coldest month for Milwaukee, Chicago, Minneapolis, Cincinnati, and many Midwestern cities. What is noticeably missing is a cold snap from the polar vortex.
We’ve already had one such instance of a polar vortex disruption where a large section of Arctic air has moved south into the lower latitudes, but that mostly affected Europe and northern Asia this month. So far, no such blast of cold air from the polar vortex has made it to the United States, and that has limited the cold air needed to keep northern precipitation as snow.
It doesn’t look like robust cold air is coming soon.
The one-month outlook from NOAA shows warmer than average temperatures across much of the country.
Even without super-cold temperatures, some Northern cities have a shot at snow this weekend.
Snow Is on the way
Winter weather alerts are in effect for over half a dozen Midwestern states Saturday in preparation for heavy snowfall. Multiple systems are moving through the region over the next few days.
Still, the upcoming snow might not be enough to bring them back to normal.
“As far as making up the deficit in Milwaukee, a few inches are possible Saturday night and Sunday morning,” says Boxell. “Monday’s system may also bring some snow, though for now it appears that the heavier amounts will be closer to the Chicago area. At this point, we will likely need multiple systems in fairly short order to make up the difference.”
From Madison, Wisconsin, to Milwaukee, the forecast calls for at least two to three inches through Monday.
Chicago, Green Bay, and Des Moines, Iowa, are all forecast to pick up one to two inches this weekend.
