Heavy rain, thunder then a temperature fall

The Chicago area's biggest precipitation- producer in nearly two months is on its way.
Rainfall commences toward midday and should build in short order into heavy downpours that
may grow thundery late in the day. At the same time, a snowstorm is to wallop an area to
Chicago's north, from the the Dakotas through the Twin Cities into northern Wisconsin
and Michigan.
The new winter storm producing the cocktail of precipitation was centered in Colorado
late Wednesday. It's the byproduct of a 100-degree north/south temperature spread.
Wednesday readings ranged from below zero on North Dakota's border with Canada to the 90s in
southwest Texas.
A shallow layer of cold air has temporarily returned to Chicago and threatens some sleet
or freezing rain at the onset of precipitation Wednesday -- especially in the north and
west suburbs. But a northbound warm front could send 50s back into the city after dark
ahead of a late-night temperature plunge.
AREA TREATED TO WARMTH WEDNESDAY
O'Hare's 54-degree Wednesday high was the city's mildest reading in two weeks and the
warmest Feb. 25 in eight years. Gary reported a high of 59 and New Lenox hit 58.
--Tom Skilling, Chief Meteorologist, WGN-TV/Chicago Tribune