Thunderstorms expected in parts of Iowa this morning never really materialized as a storm system affecting the Upper Midwest is not exactly moving through as expected. Nevertheless, most of Iowa now finds itself under a slight risk for severe weather today. To the left is the latest outlook from the Storm Prediction Center in Norman, OK, quite a departure from yesterday’s outlined area.
The expansion of the risk is Iowa represents a northern shift in the storm and a lot of uncertainty in what that exactly means. Instability is expected to build across Iowa later today in advance of a cold front. The complex nature of this forecast lies in the threat of multiple rounds of severe weather in different locations.
We begin with the primary tornado threat. Thunderstorms may develop along a secondary boundary developing and lifting north out of Missouri. This boundary would have moderate support for tornadic development in the initial hours of this event. If that were to happen, southeast Iowa would face the greatest risk of tornadoes, but current thinking is the primary risk are for tornadoes will stay just south of Iowa. You can see the risk area for tornadoes outlined in the graphic to the right.
As this severe weather event continues to evolve, we may see multiple rounds of storms move through. While a northward moving complex of supercells might take shape in southern Iowa, linear bands of storms might develop in portions of western Iowa. The greatest threat for large hail lies in the western half of Iowa while all of state faces a prolonged threat of strong wind gusts through the evening hours. You can see in the graphic to the left the entire state under a minimal risk for strong winds through the overnight hours.
Long story short, this storm system is not really playing by the rules and there is a lot of uncertainty in the current forecast. We’ll provide updates when warranted throughout the day and launch our live coverage if needed later this afternoon or evening should conditions deteriorate across the state.