For several days, we’ve been talking about a weekend storm system that has every indication of becoming a classic example of an early spring tornado outbreak here in Iowa. That forecast still appears true this morning as the state appears in line for a major outbreak of severe weather. Before we begin I want to stress this is a VERY DANGEROUS SITUATION and regardless of your interest or knowledge of severe weather, it’s imperative that you and anyone else in Iowa stay informed of what is happening. So let’s begin, starting with Saturday.
The storm system we’ve been talking about enters the weather picture Saturday Afternoon. You can see a large slight risk area now posted for the state in the graphic to the right. A warm front is expected to swing through the state as the surface low pressure system remains just to the west. This will be the focus of severe weather during the late afternoon, evening and overnight hours across the state. All modes of severe weather will be possible.
As you can see in the graphic to the left, the greatest risk area lies in portions of western and northern Iowa. Besides the possibility of a few tornadoes, the primary threat on Saturday appears to be very large hail, especially in southwest portions of Iowa. These thunderstorms may continue across parts of the state well into the night and into Sunday morning.
This is where our forecast becomes especially troublesome, as a near-perfect set up takes place right on top of Iowa. There are two distinct features that could produce a serious and widespread damaging event across the state. Sunday is a day in which I cannot stress enough the importance of staying up to date on the latest information.
As we start the day on Sunday, the warm front should be north of Iowa, leading to very warm and humid conditions across the state, especially for this time of year. A dry line is expected to develop ahead of the cold front as the surface low begins tracking through the Upper Midwest. This is where we expect widespread and rapid development of thunderstorms that could take just a matter of minutes to explode into supercells.
Overall, the atmospheric setup is nearly perfect for a major outbreak. Low level shear, available energy and a whole host of other factors are giving forecasters and storm chasers major cause for concern. As a result, as you can see in the graphic to the right, the Storm Prediction Center has already posted a moderate risk for portions of Iowa on Sunday. I would not be surprised to see some areas upgraded to a high risk for severe weather by Sunday. Again, this is a VERY DANGEROUS SITUATION. With all modes of severe weather possible, and a good chance of many tornadoes, including some strong twisters that stay on the ground for a long time, it’s safe to say at this point that Sunday has the potential to go down as a historic outbreak of severe weather.
The key problem for storm chasers on Sunday will be keeping up with these storms. It’s expected the storms could travel at a rate of between 50 and 60mph. This will also greatly enhance the danger of any tornadoes that form because they too will be fast moving and limit the amount of warnings areas at risk might see. I know I’ve already said this multiple times in this post, but it’s very important that EVERYONE stay up to date with the latest information both before the storms develop and once they begin threatening the state. A set up like this does not happen very often here in Iowa and with it being so early in the severe weather season, many could be complacent about taking the appropriate precautions.
Take a look at the graphic to the left. These are some of the highest risk probabilities you can see, especially 3 days away from a severe weather event. This is a storm that you will hear a lot about on television as it approaches. We storm chasers love a classic set up that provides us a chance to get up close and personal with a tornado, but this is different. This is the type of setup that could have disastrous consequences for any town, structure or person caught in its path. I urge everyone, especially in central and eastern Iowa to take all necessary precautions. If you plan on traveling Sunday, make sure you have a way through your cell phone or radio to stay up to date with what’s happening. Make sure you review all safety precautions you can take should the worst happen. My main goal with any storm is to make sure the people of Iowa are as prepared as possible in hopes of preventing anyone from getting hurt or losing their life. We’ll continue to bring you updates in the hours and days ahead and we plan to track these storms in the field once they develop on Sunday.