Unseasonably Cold Start to October, Frost Advisory Issued for Friday Morning

Welcome to October Stateline! Fun fact about October this year. This month is scheduled to see two full moons. Crazy right? The first full moon occurred last night, and the second one set to occur on Halloween night. But during the beginning of October, highs on average are in the upper 60s, with low temperatures in the mid-40s. I can tell you by looking at our current weather pattern that temperatures will be much cooler than that. Thanks to a backdoor cold front, highs & lows will end up well below average into the weekend. 

Temperatures to ring in the month ended up pretty chilly right before sunrise. Observed lows in most spots did drop into the low 40s, with an isolated spot or two in the upper 30s. As you prepare for the day ahead, you're definitely going to want to grab a jacket, and it wouldn't hurt to have the umbrella on hand throughout the day. Cloud cover is expected to increase ahead of an approaching cold front. This frontal boundary as of this morning is draped across northern Wisconsin. Model guidance showed this front sinking southward (hence why we call it a backdoor cold front), allowing cloud cover to increase, as well as bringing a gusty northwest wind by late morning. Winds will be not a blustery as what the Stateline encountered yesterday, but still gusts could be as high as 20-25 mph. 

Regarding today's shower chances, the best chance for rain moves in later in the day. The morning hours feature primarily dry conditions, shower chances ramping up before mid-day. As instability increases aloft, scattered showers pop-up during the prime "heating" of the day. Severe weather isn't expected Thursday afternoon, as ingredients for it simply won't be present. Hi-res models continued to keep chances through the afternoon, and lasting until sunset. Similar to the past few days, any showers moving through will feature light precipitation, and light accumulations. Mostly under a tenth of an inch. 

Turning our attention back to today's cold front, another shot of cold air will filter in behind it. This will allow unseasonably cold temperatures to settle in for the end of the work week, with a heightened potential for frost. Yes, you heard me right. There's a good chance we wake up to the first frost of the fall season Friday morning, with only a few limiting factors. How much we clear out tonight is one of them, along with how much our winds do lessen. But temperatures overnight are expected to sink down into the mid 30s for most, with a few isolated spots in the low 30s to start. 

With that being said, the National Weather Service has put out a Frost Advisory for Jo-Daviess, Stephenson, Winnebago, Boone in Northern Illinois, and our three counties up in Southern Wisconsin. This advisory will be set to go into effect at 3 AM tonight, and stretch until 9 AM tomorrow morning. What does this mean? It means this is going to mark the end of the growing season if temperatures drop low enough. Later today or even before you head to bed, make sure that you bring any tender vegetation indoors. This will ensure that tomorrow's frost potential doesn't damage your plants. Otherwise, you'll want to have a jacket on before heading off to work or school. Another frost advisory is possible across a more expansive area overnight Friday into Saturday morning.