The Storm Prediction Center has placed portions of eastern Iowa under a slight risk of severe weather. As we have seen every July, the heat and humidity during the day, leads to afternoon thunderstorm development, and this is what exactly looks to happen over the next few days.
Starting with Sunday, storms will develop along a boundary across southeast Minnesota into western Wisconsin. Storms initially will be isolated, but will quickly line out. This line, or Mesoscale Convective System (MCS) will propagate to the southeast, impacting portions of eastern Iowa. The only concern for severe weather will be damaging wind gusts. The LCL’s are too high for tornado development, and there is not enough wind shear to pose a large hail threat. As for timing, storms are expected to move through eastern Iowa late Sunday, after 8pm, and clear out by sunrise Monday. As a side note, some of the higher resolution models are now taking this line further to the east, which would mean very little impact on the state, so this trend will need to be monitored.
Heavy rain will also be a concern. While storms will be moving rather quickly, precipitation rates will be rather high. This may lead to an inch to two inches of rain in a short amount of time. This is why portions of northeast Iowa have been placed under a slight risk of excessive rainfall. The heavy rain threat with any storms will continue into Monday and Tuesday. Eventually this may pose a flooding threat, especially in areas that see repeat rainfall.
On Monday, much of the state will be under the risk of severe weather. While it is only a marginal risk at this point, we expect portions of this outlook to be upgraded to a slight risk. Looking over the models, it appears the greatest threat would extend from central to eastern Iowa. Once again like Sunday, damaging wind gusts and large hail will be the primary threats.
As storms develop over the next few days, be sure to track them and get notified before they go severe with our new FREE Storm Hunter WX app, now available on the iTunes and Google Play store.