Dense Fog Early, Severe Potential Later On

As if today wasn't busy enough with the potential for severe weather later on, mother nature threw in a layer of dense fog to kick off our Tuesday. Earlier this morning, the National Weather Service did place Green, Rock, & Walworth counties in southern Wisconsin under a Dense Fog Advisory until 10 AM. A few locations here in northern Illinois even experienced less than 1 mile visibility at times this morning. Although we're seeing improvements with the fog, it is expected to stick around into the mid to late morning hours. For those heading out the door this morning, please be sure to drive slowly, and take extra caution if you encounter any dense fog.

Regarding the severe threat later today, it all has to do with a potent area of low pressure that is sliding across the High Plains early this morning. Along with the surface low is a warm front that has been draped to the south of the Stateline all morning. As this low closes in on the Stateline, it will help lift this warm front closer to the IL/WI border by this afternoon, amplifying that severe weather potential. The placement of this warm front is one of the key factors. Most models this morning did push the front in southern Wisconsin, which will allow a warm, and unstable air-mass to roam into northern Illinois. Also, any sunshine we see early on will help heighten that potential.  

After being dry for the first half of our day, model guidance suggests showers and storms beginning to develop during the early afternoon hours, so around 1-2 PM. I think that we will see these storms initiate along the warm front across eastern Iowa, then tracking into western/northern Illinois by late afternoon. While this warm front is going to allow highs across the area to climb near 70° this afternoon, it's also going to add plenty of instability for storms to feed off of.

Per the 8AM update, the Storm Prediction Center has brought the slight risk farther northward into southern Wisconsin, which now includes a majority of our viewing area. In the categories for severe weather, a Slight Risk is a level 2 on a scale of 1 to 5. The main time frame for strong to severe storms for our region will be between 3PM and 9PM later today. There will be a small window for discrete thunderstorms early on, which will be capable of producing all modes of severe weather, including an isolated tornado or two. As the cold front slides into western Illinois by this evening, these storms will then congeal into a line, bringing more of a straight-line wind and heavy rain threat. By 10-12PM tonight, the severe threat will end, leaving few scattered showers into our Wednesday morning.

Now is the time to prepare. As we enter prime severe weather season, it is important to have multiple ways to receive watches and warnings. I know it has been quite a while since we've used our weather radios, but just make sure they are plugged in, and have fresh batteries. Turn up the volume so that you can hear the radio anywhere in the hour once a watch or warning has been issued. Secondly, be sure to have your safe place and severe weather kit ready to go.