Warm-up begins with high chance of showers

As the jet stream pattern gradually shifts from a northwest to more westerly flow the
next couple days, a cold Canadian high pressure air mass will move east. As a result,
southerly winds will return to the Midwest beginning tonight, and temperatures will begin to
rise Tuesday.
By Wednesday, northeast Illinois will have experienced some 48 hours of south winds, and
much of the snow cover -- especially southern portions -- will have melted. The melt
will accelerate as the air mass becomes more moist and showers develop. Under the right
circumstances, highs on Wednesday could well exceed 50 degrees -- but cloudy skies, scattered
showers and energy spent on melting snow all will work to restrict warming.
COLD AND SNOW RETURN THURSDAY
As a cold front eases through the area Thursday, winds will shift northeast off Lake
Michigan, and a steady light rain will probably change over to snow Thursday night. The
center of coldest air will hold to the north, but Chicago will sit in the southern flank of
the cold high pressure still partially under the influence of low pressure passing to the
south. That low may bring snow here Friday night and Saturday.
--By Paul Dailey, WGN Weather Center Meteorologist