The western portion of the state of Iowa has been placed under a slight risk of severe storms on Monday by the Storm Prediction Center. To start off, today will be dry with a mix of sun and clouds. Rain will the be possible across northern Iowa, mainly north of highway 20, later on this evening. Not a whole lot of precipitation is expected tonight from this initial wave. Another round of storms will move in from the west by Monday morning. A cold front will then push across the state by Monday afternoon, and this will bring a chance for some isolated strong to severe storms across western Iowa.
The image above is CAPE (Convective Available Potential Energy) expected by Monday afternoon. CAPE is one of many values that we look at when predicting severe weather. This tells us how unstable the atmosphere is. From the image above, the greatest amount of CAPE is across western Iowa. The pink/salmon color is 3,000 J/kg – 4,000 J/kg. To give you an idea, we can get severe thunderstorms with 2,000 J/kg- 2,500 J/kg, so there is enough instability in the atmosphere Monday to provide strong to severe storms.
One last item that I will show, is the CIN values. CIN is the convective inhibition, or also referred to as the cap. This is the value that will prevent storms from firing. From the image above, there is no cap tomorrow, so this will allow storms to fire.
We will continue to monitor the very latest trends in the models and will update you with the very latest.