Periods of steady rain overnight into Friday morning

 After record-breaking warmth Thursday afternoon, cloud cover has been thickening up. This comes along with some pockets of light rain, drizzle, and fog now entering Southern portions of the Stateline.

This area of drizzle/fog will continue to drift North through the evening, providing drops in visibility within the areas of drizzle and fog. Temperatures will only drop into the upper 30s through the evening as well. Within this drizzle/fog, we could see a few spots of light rain.

There may be a lull in precipitation rates near/just after the midnight hour, but drizzle and fog could continue to limit visibility, possibly down under a mile for some. Light winds and increased surface moisture will provide the necessary ingredients for areas of fog.

As the main low pressure system approaches tomorrow morning, steadier to heavy rainfall may be possible toward the daybreak hours. The heaviest rain is most likely between I-80 and I-90 corridors, with a sharp cutoff of the heaviest rain on the Northern edge. Some dry air in Wisconsin could limit the Northward extent of moisture.

The highest rainfall totals will likely end up along the Southern edge of the Stateline, with 0.5"-0.75" possible near or just South of I-88. Within that band, there may be some localized spots who could see 1.0" or more. Meanwhile, those in Southern Wisconsin will likely miss out on the highest rainfall totals, with many seeing under 0.25" or almost nothing.

Those who see the highest rainfall (especially near/above an inch) may have a risk for some flooding, given the deep frost depths owed to frozen ground from the Arctic chill a little more than a week ago. Most of the rain we see will be slow to soak into the soil and will have more runoff. We may also see some river flooding if the river ice builds up into ice jams.

The Weather Prediction Center highlights the risk for flooding well, showing a slight risk for flooding guidance near and South of Rockford. This translates to a 15% risk for flash flooding to occur within the yellow contour, especially between I-80 and I-88. Be aware of any potential flooding in low-lying areas and along riverways through Friday afternoon.