Brewing Up a Big One

Yet another potent storm system is starting to come together. The ingredients are in place to the west for a big severe weather outbreak later today. The graphic to the left shows that the slight risk zone just barely covers Jo Daviess County. The next shade of red indicates a moderate risk for severe weather. The darkest shading on there indicates a high risk for severe weather, which includes eastern Nebraska and western Iowa. The Storm Prediction Center has stated that in that high risk zone there exists a 30% chance for a tornado to form within 25 miles of any given point. 30% does not sound like much initially, but when we are talking about tornadoes that should put folks in that area on alert this afternoon.

The graphic on the right shows the slight risk zone for severe weather for Friday. It engulfs the entire Stateline viewing area. For tomorrow, our winds at the surface will be in almost the same direction as the winds in the jet stream (WSW). Due to the lack of wind shear or the unidirectional aspect of the winds in the atmosphere our tornado threat will be greatly reduced. Without rotation in the atmosphere it is hard to spin up a tornado. Some small hail is possible, but our main threat will be damaging winds in excess of 55 mph. I would expect to see some bowing structures on radar tomorrow to indicate the initial gust front as these thunderstorms move through the region. The heaviest rain appears to be setting up to fall during the morning hours with some scattered activity in the afternoon. Rainfall totals in most locations should sit between 0.5" - 1.0". Some spots that get stuck under the stronger thunderstorms could break the 1.0" liquid mark. -ADAM