As alluded to in the last blog, anytime low pressure decides to track through the Badger State during the summer months, it is only a matter time before the storms come to life. In contrast to a couple weeks back when daytime heating ignited the wet weather, this time the storms fired up during the night. Known as nocturnal storms, there are a couple of factors that need to come together for these strong to severe rumblers to develop. First off is the low level jet stream, which are the winds located about 5,000 feet up in the atmosphere, which have to be in the neighborhood. Not only does this flow of air bring in the moisture, but also helps push the storms in whichever direction the jet stream is aligned.  Certainly the low level jet was located over the middle of the state. Next we've got to have some sort of trigger, whether it is a cold front or in this case a meso-scale wave of low pressure. If you were watching on 24/7 Weather late Sunday night, this small scale low was clearly defined as the warm front pushed the rain into our region, followed by the low and associated cold front that really riled up the thunderstorms.

When all was said and done there was hail up to penny size reported near Vesper, possible funnel clouds in Curtis and Owen, along with downed trees both in Rib Mountain and to the west of Medford. Additionally storms, one after the other, known as training, pounded Taylor, southern Lincoln and Langlade counties with anywhere from 1 to 4" of rain in just a couple of hours. The cause of the wind damage in Rib Mountain was a microburst, which is a down draft of wind from a thunderstorm over a small area. In this case, winds upward of 60 mph were possible with the storms as they tracked across Marathon County. The potential for wind damage was evident on radar just after 1am Monday morning by the bowing of the storms as they picked up speed through Central Wisconsin.

Now...on to the heat. The last time we hit 90 degrees in the area was way back on June 23rd and 24th. Since then, an upper level trough has been solidly in place from the Great Lakes to New England, leading to somewhat cool and fairly dry weather. A change is in the works for late week as the high pressure "heat pump" out west finally starts to slide east. This will not only give us an infusion of highs well into the 80s to lower 90s, but also crank up the humidity. With that, in time, will come more opportunities for thunderstorms.

Enjoy the Wisconsin Valley Fair this week in Marathon Park and certainly the comfortable weather conditions through Friday!