Early Season Winter Storm Moves in Sunday

Winter Storm Warnings have been issued for all of northern Illinois and parts of southern Wisconsin through Sunday evening as an early season winter storm takes aim on the Midwest.

Mostly cloudy skies will continue through Saturday night into Sunday morning.  Low pressure currently located over the panhandle of Oklahoma will strengthen as it moves into Missouri Sunday morning, and then into central Illinois by Sunday night.  A mixture of snow, rain and sleet will be likely mid-morning Sunday before transitioning over to snow during the early afternoon.  The latest run of forecast models have pushed back the onset of precipitation by a couple hours Sunday morning, closer to 8am/9am, rather than the pre-dawn hours.  The transition over to snow, once it occurs, will be quick as heavy and wet snow will occur by the afternoon.  Snowfall rates up to one, to one and a half, inches per hour will be possible through the afternoon and evening.

As low pressure moves out of central Illinois Sunday evening winds will increase from the North and Northeast, gusting to 35 mph.  Blowing and drifting snow will be likely Sunday evening/night and early Monday morning.  The window of opportunity for travel may open up a little more into the afternoon, especially if the bulk of precipitation doesn't occur until the afternoon and evening.

Bands of heavy snow will be likely over parts of the Stateline where snowfall totals of 6"-9" will be possible.  Locally higher snow amounts can't completely be ruled out, however.    High amounts of moisture in the atmosphere and temperatures in the low to mid 30's will cause the snow to be heavy and wet, otherwise known as 'heart-attack' snow.  Slushy accumulations on the roads will be possible through early afternoon, with snow covered roads likely by Sunday evening and night.  Travel is not advised later in the day Sunday and impacts to the morning commute are possible Monday.