Freezing rain and heavy rain possible through Tuesday

 

A WINTER WEATHER ADVISORY has been issued for Walworth County in southeast Wisconsin beginning at 6pm Monday night and for Green and Rock counties in south-central Wisconsin beginning at 11pm.  the advisory will also go into effect for Stephenson and Jo Daviess counties at Midnight, lasting through Tuesday afternoon.

A FLOOD WATCH has been issued for Winnebago, Boone, Ogle, Lee, DeKalb and McHenry counties beginning at Midnight and lasting through Tuesday morning.

A complex winter storm system is moving across the middle of the country Monday evening, bringing heavy snow to the northern Plains and far Upper Midwest, while heavy rain falls further south.  Sandwiched in between is the Stateline, set to receive a combination of both freezing rain and heavier rainfall Monday night into Tuesday.  Cloud cover will continue to thicken through Monday evening as moisture streams into the region.  Areas of drizzle and fog are likely to develop over the next couple of hours before a steadier rain moves in after 9pm/10pm.

Temperatures are slowly beginning to trend down, falling through the mid 30s north of Rockford.  However, as warmer air surges northward ahead of an approaching low it'll help draw a little of the warmer air back north.  This should help bring temperatures back up above freezing through most of the overnight and into the beginning of Tuesday.  The exception may be right along the state line, north of Highway 20, and into southern Wisconsin where temperatures will be border line freezing, and slightly below.  In those areas the risk for freezing rain will be higher through Tuesday morning and afternoon. 

Ice accumulations of a tenth of an inch, to at the highest two tenths of an inch, are possible in the counties under the Winter Weather Advisory.

For areas south of Highway 20 there could be some freezing rain that mixes in Tuesday morning, but of greater concern will be the heavy rainfall.  With the Flood Watch in place for counties south of Highway 20 heavier rainfall may cause excessive runoff, leading to localized flooding in some areas,

especially low lying and flood prone locations.  The runoff will also cause some of the local rivers, streams and creeks to rise.  Ice jam flooding may also occur from the rising rivers and the ice breaking apart.  Rainfall amounts will range from a quarter of an inch, all the way to three quarters of an inch, perhaps an inch, between now and Tuesday afternoon.  Thunderstorms may also occur during the overnight and early Tuesday which would increase the risk for heavier rainfall during that time.  Some of the storms could also produce some small hail.

Temperatures will slowly begin to trend downward throughout the day Tuesday, falling into the teens Tuesday night.  For areas that are under the Winter Weather Advisory, slick conditions due to ice accumulations are possible.  Please take extra caution while out Tuesday morning and afternoon!