2020-03-19 EVENT: IL/IA/MO/AR/TX

[Chris Demeniuk]

I have no plans to leave home yet.

^ This right here. This was the winning move yesterday, IMO.

I was itching to go back for a do-over after getting Broyled last week in western KY. I packed some food and water, grabbed some sanitizing wipes, hermetically sealed myself in my truck, and made the trek back to about the same area as 3/12, but stayed north of the Ohio river this time, targeting extreme SW IN (IA was outside of my range for the day). And just like before, despite decent parameters, a supportive wind profile, a few brief breaks in the cloud cover, and continuous SPC agreement, all that occurred in the target area were a few sporadic wind gusts. There were a pair of tornado warnings for a mesovortex circulation embedded in a fast-moving linear segment, but the area of interest was shrouded in rain. As far as I know, no tornadoes were confirmed from that storm. That was about the peak of the excitement. Tail-end Charlie produced an isolated storm with a small hook-shaped appendage near Mount Vernon, but with no clearly defined mesocyclone, I didn't have high hopes. It fell apart right around sunset. No photos worth sharing.

One of these days I'll learn to dial it back a bit on these March setups. But I figured this may have been the last shot I get for a while, until the Covid-19 situation stabilizes.

Total chase time: 18.5 hrs. Total miles driven: approx. 950.

 

[Nick Dewhirst]

Based on yesterday’s storm reports in the tornado watches, today’s wind event across Ohio and especially upstate NY should’ve warranted a severe thunderstorm watch. There was more concentrated severe reports across upstate NY today than any region yesterday, though the hail event in IA/NE might be a similar concentration.

Not to rip on the SPC, but I think they need to be more aware when it comes to severe events with little instability. Based on yesterday’s enhanced risk (max CAPE ~ 1500 J/kg) compared to today’s marginal risk (max CAPE ~ 400 J/kg), I think their awareness of potential severe weather increases with instability values. That is a very unscientific statement, but I’m just trying to get my point across.

They issued 2 MCDs today, each acknowledging potential for isolated severe wind gusts because of strong low-level winds. But when you have 55 kt winds at 1km, shouldn’t that be of more concern than a marginal risk? In my opinion, yes. To their credit, they did say, “even minor momentum transfer from the ongoing line of shallow showers will likely result in near severe wind gusts where the boundary layer is not overly stable.”

But I think when there’s little instability available, our minds as weather enthusiasts/meteorologists want to write off an event with great kinematics as a bust. But to clarify, if you aren’t looking for this type of event, you will probably miss it.

Coming from Michigan, I’ve learned to stop myself from doing this because we usually only see appreciable instability from May-September (sometimes a bit earlier/later) In fact, I get excited when I see these super high shear/very low CAPE setups because you can really get freak storms out of them. I experienced one in late November of last year: no warning (not even a special weather statement), 65-70 MPH gusts, wind-driven small hail (very surprising), extensive tree damage, and widespread power outages in my area.

Not only that, but look what happened in MD/DE/NJ/southeast PA in early February. They had the biggest tornado outbreak there EVER there in the month of February, alongside widespread damaging winds. There wasn’t even a thunder category until after the first severe warnings were issued, but it was too late once the marginal risk was issued. Even if you have almost no instability, but you see 60-70 kt flow at 1 km and a rapidly deepening low immediately north of that, shouldn’t you have more concern than only expecting some isolated severe gusts?

This doesn’t all apply to yesterday’s events, but I felt the comparison to today was appropriate to bring up alongside other examples.