Things appear to be coming together for a potent storm to affect the Stateline as we approach the upcoming weekend. There's strong agreement amongst a number of our supercomputer models suggesting a broad area of low pressure will develop and strengthen over the Northern and Central Plains on Saturday. A warm front is slated to lift well North of the area into Central Wisconsin, and with a cold front several hundred miles to our West, strong southerly winds are to pump up some of the mildest air in two weeks in our direction!
The arrival of the warm air will create a fairly unstable atmosphere in the region, which is the first of many ingredients that will work together to promote a sizable severe weather threat into Saturday's afternoon and evening hours.
Secondly, in addition to the strong winds here at the surface, winds will be quite hefty in the middle and upper levels of our atmosphere! Winds at just 5,000 feet aloft may race to 65-70mph at times, which is very conducive to promoting a severe wind threat with any fast-moving storms that develop!
The area of low pressure, both at the surface and aloft, is a broad one, and will be in a strengthening phase as the storm lifts closer to the Stateline!
Finally, and perhaps most importantly, wind shear in the atmosphere looks to be quite impressive! Wind shear, you may recall, is the changing direction of winds with height. Current suggestions are that winds at the surface will be out of the SSW, while out of the SW at 5,000 feet, and WSW at 15,000 feet! Such "veering", as we call it in the meteorological community, of the winds promotes rotation within storms, which means a tornado threat would at least be worthy of mention!
With this in mind, the Storm Prediction Center highlights a good chunk of the Midwest and Western Great Lakes regions to be on the look for potentially severe thunderstorms on Saturday! It's not often areas are highlighted for possibly severe weather this far in advance, especially in October! So while there's plenty of time for things to shift course, and still plenty of uncertainty with the storm still 4+ days away, it's unequivocally a storm that bears close monitoring in the days ahead!