While the day started out on the mild side, drastic changes came for the afternoon as a strong cold front swept through. Temperatures fell from the upper 60s just after noon to the low 40s by 9PM. Even the regional high temperatures map shows the much cooler air off to the West that was set to move in through the afternoon and evening.
Overnight tonight, the cold air really takes hold as temperatures fall into the low 30s for most. Wind chill will be a small factor, with wind chills as low as the mid-20s overnight. Skies will gradually clear after the more overcast afternoon and evening.
A FREEZE WARNING is in effect for Jo Daviess, Stephenson, and Carroll counties in NW Illinois, along with Green County in Southern Wisconsin. These locations are where temperatures could dip into the upper 20s, bringing the first hard freeze.
High temperatures tomorrow will be more than 20 degrees cooler than they were the night before. Despite some early sunshine, the cold air mass takes hold, giving us afternoon highs only in the upper 40s.
Clouds increase again into Saturday night, but rain chances hold off until closer to midnight. Moisture content remains highest to the South, which is why the highest coverage of rain will remain that direction as well. We could see spotty showers through daybreak Sunday before some dry time ahead of additional showers during the afternoon.
Our next system following the weekend will help to usher in a fresh batch of cold air by Halloween. A clipper-like system will pass by, bringing with it a low amount of moisture. This moisture along with the cold air aloft may be just enough to produce some spotty snow showers during the afternoon and evening on Halloween. Regardless of if we see precipitation falling from the sky, Halloween will be cold and breezy, so plan accordingly for those costumes!
Cooler than average air will settle in for the last few days of October leading into the first few days of November. Afternoon highs will remain below 50° between Saturday and Wednesday before temperatures start to moderate into the end of the week. Rain chances settle in Saturday night and Sunday afternoon/evening, followed by spotty snow showers possible on Tuesday.