After another cold air outbreak through the end of the week, it's always nice to know there are mild temperatures on the way (for winter in northern Illinois that is). We're keeping our eyes on our next low pressure system that will arrive out of the Rockies to start next week. While the system is several days away and can change, the current possible track currently is to take the low just north of, or overhead of northern Illinois and southern Wisconsin. This would put us in the 'warm sector'.
Starting on Monday, a weak front will be lifting northeast across northern Illinois from Iowa. With increasing lift and moisture, and still chilly temperatures, light snow will be possible late in the day on Monday into Monday evening. with low moving overhead, light snow will then mix with rain as warmer temperatures surge north. Temperatures Monday will stay below freezing, but it will be warmer near 30°. Tuesday will be the warmest day in the next 7 days with highs making it into the upper 30's to near 40°. The mix will then transition to all rain on Tuesday before changing back to light snow by Tuesday night. A cold front passes into Wednesday and brings dry air which ends the snow, and ushers in colder air which drops temperatures once again into Wednesday. This system doesn't look to bring much in any accumulating snow, but messy weather to start the week.