Wind and rain move in late Wednesday, into Thursday

 

Temperatures have slowly been rising Tuesday evening thanks to the arrival of cloudy skies and a southerly breeze. After a little bit of a dip in the mercury just after sunset, temperatures have begun to rise back into the low to mid 30s and will remain in the 30s until a weak cold front passes early Wednesday morning. This will briefly push temperatures down into the 20s around daybreak, leading to a partly cloudy sky for most of Wednesday afternoon.

Even though a cold front will have passed temperatures will slowly begin to warm as winds turn back to the south during the afternoon and evening. This is ahead of a strong storm system that'll move across the northern Plains and Upper Midwest Wednesday evening before moving into the Upper Great Lakes Thursday. Ahead of the low a warm southerly wind will help push temperatures late Wednesday evening into the upper 30s, likely reaching the low 40s early Thursday. Increasing winds within the low-level jet (winds just a few thousand feet above the surface) will increase which will not only cause our surface winds to increase during the overnight but also help transport more moisture into northern Illinois and southern Wisconsin.

This increase in moisture will lead to a quick development of showers Thursday morning with a steady rain developing by mid-morning. A few rumbles of thunder are possible across central and east-central Illinois. Rainfall totals will end up around a quarter of an inch once the rainfall comes to an end early afternoon.

A strong cold front will move in around Noon Thursday with temperatures beginning to fall from

west to east, down into the 30s during the afternoon and then into the 20s and eventually teens Thursday evening. Most of the moisture will be to the east by the time the colder air arrives, but a few snow showers could briefly mix in behind the initial batch of rain, with a few snow showers and/or flurries developing late afternoon and evening. Northwest winds will increase following the front with gusts approaching 35 mph through Thursday evening.  

The quick drop in temperatures Thursday could cause some issues with slick conditions Thursday evening and overnight, especially following the recent snow melt and rainfall Thursday morning. The incoming rain could wash away some of the recent road treatment from previous winter systems, which means that the wet roads (especially the lesser traveled roads) could become icy when the temperatures drop during the evening.