A storm system is forecast to sweep across extreme southern Iowa and northern Missouri, bringing with it the threat of severe weather across portions of the state. It’s a tricky forecast for Iowa as it appears the window of opportunity for severe weather will be limited. As you can see in the graphic to the right, the Storm Prediction Center has posted a slight risk for areas of southeast Iowa. This is in the area of a frontal boundary and a weak surface low forecast to cross the area late in the afternoon and into the early evening hours.
Thunderstorms are not expected to really get going until after 4pm or 5pm. These storms will carry a good chance of severe hail (1” in diameter or larger). There is also a brief window that storms could produce tornadoes. At this time the best shot at tornadic development appears to lie in extreme southeast Iowa and northeast Missouri.
Taking a closer look at the probabilities forecast for severe weather tomorrow you can see this storm system should affect a large area of the central plains. Again the trouble for tracking this storm through Iowa is the timing and location. It’s tough to be too excited for this storm system from my perspective because the tornado risk appears somewhat conditional at this time and the possibility of having to chase storms while crossing the Mississippi River is not exciting. Anytime you throw a major river in the mix it severely limits possible routes to travel.
As the night progresses the storms should quickly move out of the state and move on to the east. This storm system is also expected to produce widespread severe weather, especially in the southeastern United States in the days to come. Again there is a brief window of opportunity for chasers here in Iowa tomorrow afternoon so we will continue to monitor the latest trends and post updates as new information comes in.