Snow-rain cocktail could be on way to city

A storm -- the byproduct of powerhouse jet-stream winds that roared into western
Canada at 220 m.p.h. late Friday -- is to spin up over eastern North America over the
weekend. While not expected to be a mammoth precipitation-producer in Chicago on
Sunday into Monday morning, it may generate the first accumulations of non-lake-effect
snow here this season. The form the precipitation takes -- a wet snow or a rain/snow mix
over at least part of the metro area Sunday, trending to all snow at night -- has not been
definitively settled. But, the potential for at least some accumulation, possibly enhanced
by lake-effect snow showers Sunday night, seems pretty solid. A suite of computer
projections places likely water-equivalent precipitation tallies in the 0.20 to 0.35-inch
range. Were that to come as all snow, it could fluff up to 1 to 4 inches. But, the first
accumulations of the season -- this one included -- occur on warm ground and
pavement amid winds off the still "warm" waters of Lake Michigan. That can cut into snow
totals -- or even lead to a rain/snow mix at times.
Snow measurements over the past 124 years indicate the chance of at least an inch of
snow by Dec. 1 in Chicago is 60 percent.
--Tom Skilling, Chief Meteorologist, WGN-TV/Chicago Tribune

Posted by wgnweather at 11:12 PM | Permalink

Four key factors make amount of snow that accumulates Sunday a dicey call