Intense Storm Headed For
The Great Lakes Region
A rapidly strengthening low pressure system will track from Iowa to southern Lake Michigan overnight...moving northeast of Lake Huron by early Sunday evening. The image below shows the Low's position around Noon on Sunday.
The warm air in place initially will result in an hour or two of rain at the beginning of the precipitation late tonight. As the colder air pours in on strong northwest winds, the temperatures will rapidly fall below freezing and turn the rain to snow. A couple hours of heavy snow is possible Sunday morning before the snow tapers off and ends. The changeover to snow is expected around 5 am at Madison and 8 am at Milwaukee. Current indications are that the heaviest band of snow will extend from near Madison to Fond du Lac.
As the low deepens and moves across lower Michigan Sunday, west to northwest winds will really increase across southern Wisconsin and especially toward the Illinois Border and along Lake Michigan. Gusts of 50-55 mph are expected, which may result in tree damage and power outages. Since there will be a period of rain and wet snow, there is a good deal of uncertainty on just how much blowing and drifting snow we will see. It will be a race against time to see how dry the snow becomes before the snow tapers off. If there is a longer period of colder and drier snow, then we could have blizzard conditions develop for a time across parts of south central and east central Wisconsin.
The biggest danger with this storm will be the intense westerly winds that will develop, coupled with the newly fallen snow. West winds could gust to as high as 50-55 mph with blowing snow possibly restricting visibility to 1/2 mile or less at times. Holiday travelers could find road conditions turning very hazardous, especially as initially wet roads turn icy and snow covered as the temperatures fall below freezing Sunday.
Steve Davis and Jeff Craven
National Weather Service Milwaukee/Sullivan WI