Decoding the Parkersburg EF5 Tornado

Okay, Trey, let's go ahead and get into it.

How did the secondary surface low in that weird north-south warm front set the stage for such a long-lived EF5 tornado?

This was a really unique case, especially with the surface features.

You had a surface low up in northwest Minnesota, cold front stretching down to a secondary surface low in the northern Iowa, southern Minnesota vicinity.

Then from that to the southwest, you had your cold front, but to the southeast of that, you had a warm front that was draped basically almost north-south, which is quite unusual.

Your typical schematic of a mid-latitude cyclone or surface low has your cold front down to the south, warm front off to the east.

That was not the case in this scenario.

The warm front was actually draped much more north-south.

So you'd think with more east or northeast moving storms that they would be easily crossing that boundary into the cooler air, which was not favorable for tornadic activity.

But the warm front was actually slowly shifting east with the actual storms as they developed, so those storms were able to remain in that warm frontal zone or near that warm frontal zone for a long duration as they moved in concert with one another.

That allowed them to remain significantly tornadic for quite a long period.

Just a couple of patterns I'm starting to notice as I get these opportunities to talk with you more about severe weather.

It seems number one, whenever the larger scale features are moving along with the storms, it really provides an opportunity for some explosive things to happen.

And then number two, I think you mentioned the orientation of the warm front.

It seems like whenever there are these very strange setups, modeling out how you think it's gonna go just doesn't always work out that way because it is so novel that there are just so many factors that can come into play to change up what you think you know.

Yeah, I can't really recall a specific analog to this case where you had almost a due north-south oriented warm front like this.

Obviously, as we said, that's usually not good.

Any type of boundary that's oriented more perpendicular to storm motion is gonna be unfavorable for those storms remaining near that boundary, and they tend to cross it pretty quickly and become elevated or non-tornadic.

That just wasn't the case here, even though you had a north-south warm front.

So this was very unique, and this was if you just did a quick glance at the surface obs, you probably wouldn't see this.

You had to do some detailed analysis to actually pick this out.

It goes to show that it requires a very astute look and detailed look at the surface observations and all of your products before you actually select a target and adjust from there.

Now, if you're a forecaster who's watching this situation in real time, you see a supercell anchoring to a warm front, what should you be looking for at that point? And obviously storm chaser is implied here as well, but just what is the overall thing that should take over in your mind when you see a situation like this?

So when you see a storm anchoring, that's usually gonna, going to involve a pretty s- distinct change in character.

The storm might be relatively outflow dominant or just not all that impressive.