Chicago prepares for brief wintry assault

CHICAGO - Back-to-back 60+ days in February are rare. We just had one pair Wednesday and Thursday. It seems likely we will achieve that thermal feat again Monday and Tuesday with an outside chance of a 60 degrees even on Sunday. 

Before all of that frivolity, we will be dealing with a rather stunning change of atmospheric temperament this afternoon. The day opens with abundant sun and mild temps by late-February standards. We should reach at least 50 degrees in most areas before a "back door" cold front sweeps in from the north. Temperatures will tank and some rain will begin to fall.  

As temperatures aloft and at the surface drop, the rain will change over to wet snow, likely in time to have some impact during the evening commute.  Accumulations will be difficult due to how warm it has been lately, but by tonight, there could very well be some coatings on grassy surfaces and such.  

The big question is lake-effect snow in northeastern Illinois tonight. There should be a narrow ribbon targeting mainly eastern Lake and eastern Cook counties. It would be cold enough for a modest slushy accumulation of perhaps an inch.  It would end early tomorrow morning with sunshine prevailing for the rest of the day. Highs not far from 40. 

Then, we crank up the good ol’ February we’ve come to know and love with highs way into the 50s on Sunday then 60+ Monday. There could be a shower Monday night but Tuesday afternoon looks more ominous. Thunderstorms, possibly severe, will be in or close to Chicagoland as highs flirt with 70 degrees. Wednesday would be a transition day followed by another brief cold shot on Thursday to close out the month.