NOTE: The first paragraphs were composed before the complex of storms entered northwestern Iowa earlier this morning.

The Storm Prediction Center in Norman, Oklahoma has posted an enhanced risk of severe weather today across much of eastern Iowa, including Waterloo, Iowa City, Cedar Rapids, and the Quad Cities.

There are multiple uncertainties revolving around this risk today. The primary reason is an ongoing Mesoscale Convective System that is trekking it’s way across the Plains and eventually into Minnesota and northwestern Iowa this morning. A Severe Thunderstorm Watch has already been posted until 9:00 a.m. with the possibility of locally 90 MPH damaging wind gusts with a bow echo moving through. The major unpredictability with this is that there is no for sure on how the MCS will run. How long it lasts, whether it’s a bow echo, discrete supercell complex, or other forms, and multiple other factors are just a few reasons why the forecast for the storms expected later on today is hard to write.

The synoptic setup for today will be interesting. A Mesoscale Convective Vortex, or essentially a mini-low pressure system, that will be left behind from the storms from Minnesota will serve as a focal point for development with a warm front draped across Iowa. Depending on how far east the MCV sits, warm air advection will push a lot of moisture into the Great Lakes with dew points in the 60s and 70s. Where the MCV will sit – as noted – will be the unknown. This could have a dramatic effect on the forecast later today, so it would be a good idea to check back around noon to see where things sit.

Predictability is also low on whether we will see initiation near the MCV left behind in the Great Lakes region, along the front in eastern Iowa, or both. Either way, there is plenty of shear available to get things enhanced very fast. Instability will be another story. If things can clear out, instability should be plenty and potentially lead to a significant day across the Midwest with very large hail, damaging winds, and strong and long lived tornadoes. Current expectations have storms firing near the MCV with further development on the front which will likely sit from Mason City to Burlington, or about where the enhanced risk starts. It would be a good idea for anyone in the included area to keep an eye on the weather this afternoon and evening.

Sunday

 
Another system is forecast to drop into the state from the northwest on Sunday. This could produce some showers and thunderstorms along it. It’s too early to determine any severe weather risk at this time, but we’ll keep tabs on it over the coming days.