Let’s keep it rolling. Why not.
Per Lot:
EXPECTATIONS ARE THAT TOP-DOWN SATURATION WILL RESULT IN A PERIOD OF LIGHT SNOW SPREADING WEST TO EAST OVER THE ENTIRE AREA, REACHING THE I-39 CORRIDOR BY MID-AFTERNOON AND THE CHICAGO METRO AND NORTHWEST INDIANA BY LATE AFTERNOON. MOST GUIDANCE HAS BEEN CONSISTENT IN GENERATING QPF GENERALLY IN THE 0.15-0.20 INCH RANGE, WITH HIGHER AMOUNTS OF AT LEAST 0.25 INCH IN THE BROADER ENSEMBLE ENVELOPE SOUTH OF I-80. MEANWHILE, A 3KM DEEP DGZ INTERSECTING WITH MOST OF THE MID-LEVEL ASCENT WOULD SUPPORT A HIGHER RATIO SNOWFALL ON THE ORDER OF 15:1 TO EVEN 20:1. PUTTING THIS TOGETHER, A WIDESPREAD FLUFFY SNOW EVENT OF 1-3" NORTH OF I-80 AND 2-4" SOUTH OF I-80 APPEARS LIKELY. HAVE SOME CONCERNS THAT THE 600 HPA F-GEN NOTED ABOVE WILL FOCUS A NARROW (COUNTY-WIDE) WSW TO ENE ORIENTED BAND OF HIGHER QPF AND HIGHER SLR (>20:1) SOUTHEAST OF I-55 IN THE EVENING. IN THIS CASE, IT IS FEASIBLE THAT A NARROW 4-6" BAND OF SNOW WILL BE REALIZED. FINALLY, WHILE NOT EXPECTED (10% CHANCE), SYNOPTIC ENHANCEMENT OF A DEVELOPING MESO-LOW OVER SOUTHERN LAKE MICHIGAN TONIGHT COULD BACK CLOSE TO THE ILLINOIS SHORE AS THE LOW-LEVEL SYNOPTIC FLOW TURNS SSE EARLY MONDAY EVENING. WILL THEREFORE NEED TO MONITOR FOR LOCALLY HIGHER SNOWFALL TOTALS ALONG THE IMMEDIATE SHORE FROM DOWNTOWN CHICAGO TO THE IL/WI LINE.