The first Tornado Watch (close to Upper Michigan) of the season has been issued by the Storm Prediction Center (SPC) in Norman, Oklahoma. The watch encompasses much of Wisconsin right up to the U.P. border. It??s in effect until midnight Central Time. SPC says the air is unstable enough (high humidity) and there are strong enough winds blowing in different directions through the atmosphere for the possibility of a few tornadoes in the watch area. Along with the tornado threat, there is also the possibility of damaging wind gusts up to 70mph and hail up to one-and-a-half inches in diameter.
The fact that Upper Michigan skirts the northern border of this watch means that we will have to be on watch, too, especially in the counties bordering Wisconsin. I think the main threat will be early this evening as heating from the sun enhances instability. The thunderstorms developing upstream in central Wisconsin are heading northeastward at a pretty good clip. We??ll keep an eye on them as the move and develop closer.