Thinking largely remains the same from yesterday with only minor adjustments to shift the heavy snow band a tad south. A heavy march snowstorm is forecast to affect portions of Central IL Friday evening into the day on Saturday. This system will likely be a heavy snow maker for areas along and north of I-74. The low pressure system has begun to develop across the western plains this afternoon. The surface low will continue to move southeast during the day remainder of the day today and should be near or just south of STL by around early tomorrow morning.While there is still some uncertainty regarding the exact placement of heavy snow, the models have come into better agreement than 24 hours ago. The heaviest snow appears to be along and especially north of I-74. The map below shows forecast snowfall amounts for the all of Central IL.
The snow will likely begin late Friday evening between 8-10 pm across far NW IL. The snow should move southeast across the remainder of IL overnight Friday. The southern extent of the snowfall is still somewhat questionable, but It currently appears that rain will likely change over to very wet snow even a little south of I-74 during the day Saturday, with more of a mix of rain and snow south of that region but north of I-72. Precipitation will end from west to east late Saturday afternoon with precip diminishing across Central IL by early evening Saturday. Within the zone of heaviest snowfall, rates may reach 1-2” an hour and with gusty winds, travel will be difficult, especially early Saturday morning. Cannot rule out some sporadic power outages in the zone of heaviest snowfall (across north Central IL) with very heavy wet snow and gusty winds. This may cause some tree branches to break and fall on power lines.