LINCOLN — Don't expect a repeat of last winter's mild temperatures and meager snowfall, says National Weather Service meteorologist Ed Shimon.
Last winter tied for sixth-warmest in Champaign-Urbana weather history, and ranked No. 9 in least amount of snowfall. The average temperature in December 2011, and January and February 2012 was 34.1 degrees, more than 6 degrees above normal. And Champaign-Urbana recorded just 10.9 inches of snowfall.
"In an average winter we'll normally get snowfalls in the 20-inch to 25-inch range. That's significantly more than last year. It would at least double last year if we have a normal winter," Shimon said. "People are going to need to be ready. You can't expect a year without winter two years in a row."
And as the Climate Prediction Center updates its winter weather outlook, it is trending "toward a normal winter if not slightly below for temperatures," he said.
"It looks like they have shifted things from the initial October outlook and we're a little bit closer to slightly below normal temperatures, although we in central Illinois remain in the equal chances of above normal and below normal temperatures," Shimon said. "But they have added some below normal temperatures in the upper Mississippi River Valley down to northern Iowa. That puts us a little closer to where we might be trending toward the colder side of normal periodically."
And the 90-day precipitation outlook has shifted the center of the above normal area to Tennessee, extending up to southern Illinois.
"We're definitely closer to the above normal precipitation area instead of the below normal," he said.
The shift to winter weather could begin soon.
"There's a little bit of a change from the original winter outlook," Shimon said. "As we get into December we may see some more storm systems rolling through, and the orientation of the precipitation is that they'll be storm systems moving from Texas through southern Illinois into Ohio. Those usually give us quite a bit of moisture because they tap into the Gulf of Mexico for a moisture source, as opposed to those clippers that come out of Alberta or southern Canada and scoot across Minnesota and northern Illinois. They usually bring us a short burst of precipitation but not a lot of moisture because they don't have the southerly winds ahead of them to help drag moisture out of the Gulf. Those storms out of Texas can really dump a lot of moisture on us. It looks like we may have a couple of those systems projected for December, based on the Climate Prediction Center."
The first snowfall of the season could arrive Monday night, Shimon said, although it will be light.
"One storm system trying to come in for Monday keeps shifting to the south, which means that we'll probably be more on the dry wide of it," he said, "but we could have brief period of snow Monday night."
Last winter's first measurable snowfall — three-tenths of an inch — didn't arrive until Dec. 9. The biggest storm of the season was 4 inches on Jan. 13.