March 26--Clouds depressed temperatures Wednesday, with highs topping out only in the lower 40s, but that, along with the early morning rain, was enough to erase remnants of the 6-inch snowfall the Chicago area received just two days prior.
Some sun will return Thursday, but with a huge buckle in the jet stream aloft, strong northerly flow will steer midwinter cold Canadian high pressure into the Midwest and western Great Lakes.
The first surge hits Thursday, with high temperatures struggling to rise into the 40s, but the coldest air hits Friday, with daytime highs reminiscent of January -- lucky to reach the 30-degree mark.
Should the high Friday top out at the forecast 31-degree mark, it would rank in the five coldest March 27s in Chicago's 144 years of record.
At the surface, northerly winds will glide down the entire length of Lake Michigan, generating lake-effect snow showers along the Illinois and Indiana shoreline, with accumulating snow possible Thursday night into Friday.
The cold high pressure will begin to recede east Saturday, with highs still well below normal in the middle to upper 30s, but 40s are in store along with clouds and a chance of rain Sunday.
