Chicagoans are bracing for the coldest weekend in nearly two months, even though the calendar is approaching the middle of meteorological spring. The city is expecting back-to -back sub-40-degree highs at a time of year when typical highs should be in the middle 50s. Saturday morning wind chills are forecast to cluster in the single digits as brisk northwest winds combine with temperatures near 20. The weekend is expected to be dry with no precipitation expected until Sunday night, when an approaching storm system is expected to bring a round of snow that should persist into Monday morning. An inch or two of snow could accumulate, mainly on grassy areas. The snow should end before Monday afternoon’s Cubs home opener, though the game will be a chilly affair with the first-pitch temperature in the upper 30s along with a chance of a rain-snow mix.