The weather pictures is becoming a bit clearer for this weekend, as a strong storms system enters the Upper Midwest beginning on Saturday. First things first, I want to mention some marginal severe weather threats for areas just south of Iowa today and tomorrow. Although showers and thunderstorms could push into the state, at this time NO severe weather is expected until the weekend.
With that out of the way, let’s begin to sink our teeth into this set up. We begin with Saturday with a warm front that wall pass from south to north across the state, bringing with it very warm conditions. In fact record highs could fall in some areas as temperatures could soar into the middle 80’s in some areas. Although a lot of strong dynamics will be in place on Saturday, they will be joined by a rather strong cap as well. This should prevent any thunderstorms from developing in Iowa, perhaps holding off until around 7pm.
That’s when areas of southwest Iowa may see thunderstorms either develop or move into the state from the west. Although strong damaging winds and a tornado or two will be possible, it appears a late night severe weather threat will bring mostly a large hail threat to much of the state.
As you can see in the graphic to the left, the overall probabilities show a blanket 30% risk for most of the state. Again I expect this threat to be primarily hail and could turn into a late night, early Sunday morning severe weather episode. All of this will play a crucial role in the expected set up for Sunday as the storm system finally begins to push out of the area.
Factor one to worry about on Sunday is any ongoing storms in the area. It’s expected at this time that we’ll see several hours of dry weather in the morning and afternoon that will allow the atmosphere to recover for another day of severe weather.
The risk area, that you can see in the graphic to the right, has remained unchanged for at least 2 days now. A strong low pressure system is expected to move from western to eastern Iowa over the course of the day on Sunday. A trailing cold front is expected to follow that low pressure center, triggering a widespread outbreak of severe weather from Iowa all the way south to the Louisiana area.
Overall setup for tornadoes to develop as part of this outbreak appears strong here in Iowa. There are some concerns regarding shear support and for storm chasers the expected 50kt velocity of the storms that do develop on Sunday. Of course this is nothing terribly out of the ordinary. At this time we plan to take part in a chase on Sunday. More on that in just a moment. First to recap, scattered showers and thunderstorms could develop today and tomorrow across parts of Iowa. Saturday will turn into a very warm day for much of the state, leading to some later day/evening/overnight thunderstorms, some of which could be severe. The greatest threat on Saturday at this time exists in areas of southern and central Iowa.
Sunday is the day we expect to see a LARGE severe weather outbreak. All modes of severe weather are likely as storms will fire during the latter half of Sunday. Storm chasers should be on high alert for this event here in Iowa.
To get back to what I mentioned briefly, I have some news that will affect our coverage this weekend. Although we plan on chasing eventually on Sunday, we will be unable to track the weather on Saturday. That’s because of a very good thing in my life: I’m getting married! With my nuptials set for this Saturday, not only will I not be able to keep tabs on the weather but neither will anyone I work with since they too will be at my wedding.
I apologize for the inconvenience and I hope you all understand. Of course my availability on Sunday will be limited, but depending on time and track we are preparing to chase if we are able to. At the very least we hope to bring you coverage in the afternoon of any storms that develop on Sunday. Thanks for your understanding and we hope to provide you with as much information as possible this weekend.