Iowa is beginning to look like a route for a marathon, with two unusual October storm systems expected to develop tomorrow and Friday. More information on each storm is below. Additional updates will be made available as needed.
First, we must discuss the severe weather threat for Thursday. This is moreso of a classic summertime setup (even though we are nearly a week into October) where surface heating and a moist atmosphere combine to create the potential for severe weather. The current forecast has storms firing in eastern Nebraska which will move into a more unstable environment in Iowa, where large hail and damaging winds will be the primary threat. These storms should be in “clusters” and not in the usual line, but still have the same summertime effect.
The general forecast for Friday has not changed since last updated yesterday. A broad area of low pressure at the surface is expected to rapidly move in on Friday into western Iowa and continue moving east. With ample instability thanks to high dew points and perfect atmospheric conditions, supercells will likely develop across the region, especially along the surface low. The plan that this low takes will impact which threats occur to Iowa. If too fast or to quick to release, everything may fall apart and we will be stuck with a damaging wind threat. The current plan is for supercells packed with very large hail, tornadoes – some strong, and perhaps a damaging wind gust. Everything is depending on the timing of things and what this low wants to do. Currently, the area of most concern exists along a line from souhwestern Wisconsin into west central Iowa. This is the forecasted path on which the low may take and where the greatest impacts will be.