Late-season snowstorm beginning to affect the area- Ground already whitening across north portions of the Chicago area
Latest radar loop shows where the rain and snow is falling across the area.
Snow is falling heaviest in areas where the visibility is less than 1 mile.
Pink-colored counties under winter storm warning
The latest meso-scale discussion from the Storm Prediction Center highlights the transition from rain to snow across extreme northern Illinois.
Mesoscale Discussion 0459 NWS Storm Prediction Center Norman OK 1132 AM CDT Sat Apr 27 2019 Areas affected...Portions of northeast Iowa...Southern Wisconsin...Northern Illinois Concerning...Heavy snow Valid 271632Z - 272230Z SUMMARY...A potent mid-level low will bring periods of heavy snow to areas along the Wisconsin/Illinois border. Areas receiving rain now will transition to snow this afternoon before precipitation moves out of the discussion area early this evening. Pockets of 1 in./hour snowfall rates are possible. DISCUSSION...Over the course of the last couple of hours, precipitation across the Wisconsin/Illinois border has caused temperatures to wet-bulb down to the low 30s from the low 40s. Surface observations have shown rain turn to snow in southwest Wisconsin with snow now occurring as far east as Janesville, WI. Heavier areas of snow have also begun to shift out of northeast Iowa into Wisconsin. The Mineral Point, WI ASOS has been reporting moderate snowfall for the last hour. Temperatures should continue to fall into the low 30s in the eastern portions of the discussion area. Dual-pol radar observation from KDVN and KLOT continue to show the rain/snow transition line within the second to third tier of Illinois counties. As the mid-level low continues its approach from the west, increased large-scale ascent and 850-700 mb frontogenesis will support pockets of heavier snowfall, likely near 1 in./hour. The heaviest snow should gradually taper off from west to east, with eastern portions seeing heavy rates ending by about 7 PM CDT.