And here we go. A frontal boundary will set up shop across Iowa on Monday, setting up a dangerously unstable air mass across the area. Although capped for much of the day, portions of the cap should break by mid to late afternoon on Monday, leading to explosive thunderstorm development.
As a result, the Storm Prediction Center has posted a MODERATE risk for severe weather for much of the state. The primary threat area will be wherever the frontal boundary sets up shop. This is where a combination of instability and vertical shear profiles will be supportive of supercells capable of producing tornadoes.
As of this morning, the current target area for this explosive development is the Highway 20 corridor in northern Iowa, especially in the western half of the state where a “triple point” may set up. The triple point is where the warm, cold and occluded front intersect. This would be target area #1 for rapid tornadic development.
Beyond this area, storms are expected to continue throughout the evening. Severe weather may persist into the overnight hours and there could also be a sustained tornado threat for several hours, even after sunset. All in all it’s shaping up to be a major threat. You can see in the graphic to the right that most of the state faces a high probability of severe weather.
So the bottom line, the potential for a serious outbreak is growing for Monday and needs to be closely monitored. If you have outdoor plans on Monday afternoon or evening it’s imperative that you have some way of keeping up with the latest weather forecast. We will continue to provide updates on this severe weather threat and will have more on Monday’s severe weather outlook this afternoon.