2024 Tornado Bonanza Continues

2024 Tornado Bonanza Continues

June 2024

Happy June!  I hope your May was as good as mine.

I just returned from a highly successful storm chase vacation. Amazingly, we tracked 9 tornadoes in just three days.  And most of those came from the amazing Windthorst, Texas tornadic storm on May 25th.  It had one of the best combinations of tornado and supercell structure that I've ever witnessed:

And, as amazing as that storm was, there were even more stunning storms before we arrived.  And arguably, the most violent of these was the wedge tornado that hit Greenfield, Iowa on May 21st.

GREENFIELD, IOWA EF4

This storm truly was one for the ages. In progress for nearly an hour, this intense tornado hit the small town of Greenfield near the end of its path.  The Doppler on Wheels, which were collecting data during the tornado, measured winds of at least 250 mph in the funnel:

Very prelim analysis of DOW data show
>250 mph peak winds, possibly high as 290, at 44 m (144 ft) above ground in Greenfield, IA. Tornado very intense & also very small, so worst winds were in narrow swath. Raw data from DOW7 (L); Prelim DOW-measured center path. POD blue dot (R) pic.twitter.com/bDXZilk2aD

— Doppler on Wheels (DOW) (@DOWFacility) May 22, 2024

Unusually, this tornado formed within a barely-broken line of supercells. You see, the vast majority of the time, intense tornadoes form in isolated cells. But not in this case!

Incredibly, Reed Timmer and his team were able to get terrific video of this tornado within the rain:

Check out this whip-like vortex in the #tornado south of Greenfield, Iowa with @theScantman on the controls. Full 4K video is on YT WATCH: https://t.co/SQHq4Cwmwg pic.twitter.com/FyBbaHxUuV

— Reed Timmer, PhD (@ReedTimmerUSA) May 22, 2024

 Certainly one of the highlights of 2024!

EL DORADO, OKLAHOMA EF2

Perhaps the most chaser-friendly tornado of the season occurred on May 23rd.  A highly-visible tornado formed near El Dorado, Oklahoma, and slowly tracked over rural areas for almost an hour.  Meteorologist Cameron Nixon of the Storm Prediction Center had a front row seat:

This was all one tornado

📍Eldorado, OK pic.twitter.com/yCmqD9yyOm

— Cameron Nixon (@CameronJNixon) May 27, 2024

Like Greenfield, El Dorado had a bevy of mobile radars surrounding it. One of the radars was Doppler on Wheels 6, which recorded ~210 mph winds in the funnel:

Pending QC for further refinements but preliminary data from DOW-6 45mins ago showing several bins in excess of 210mph ~150m AGL!!! #okwx pic.twitter.com/MWFBrjIsaz

— 📡 Bryan Wilson 📡 (@DualDoppler) May 24, 2024

Later, Texas Tech's Ka-band radar captured the tornado going through a vertical cross section:

But the most stunning part of the dataset was our capture of continuous (every 6 sec.) RHIs at an azimuth upstream of the tornado. We captured the tornado crossing it which will allow us to do a full 3d reconstruction, including the rarely observed boundary layer structure. pic.twitter.com/hTObejALKo

— Alex Schueth (@ASchueth) May 25, 2024

This is extremely rare, and will greatly benefit our understanding of the vertical structure of tornadoes.

TORNADO SCIENCE MINUTE

Once again, the EF-scale became a subject of conversation in May. Since several high-end tornadoes were sampled by mobile radars, questions emerged as to why the tornadoes were not rated higher.

For example, the Greenfield, Iowa tornado contained winds of at least 250 mph -- well above the 200 mph EF5 threshold:

Yet, it was rated EF4.  Why wasn't it rated higher?

It turns out that the EF scale is calibrated based on 3-second gusts at 10 meters above ground level (p. 14 in this document).  However, mobile radars measure instantaneous wind speeds at some distance above ground level. So, these measurements are, unfortunately, apples and oranges.

That said, there has been some work to correlate these two measurement types.  In fact, a recent paper by Karen Kosiba and Josh Wurman suggests that mobile Doppler wind measurements may underestimate tornado velocities at ground level.

But, for now, the National Weather Service has decided to limit ratings to observed damage.  A plan to update the scale, possibly including radar data, is in the works.

CHASE TIP OF THE MONTH

One of the most important things I've learned while chasing is that you need a good forecasting process. What I mean is, a set of parameters that you check every time you go out -- basically, a checklist.

The reason for this, is that if you don't run through it all at least once, you may miss key atmospheric details.  And these are the things that can make or break your chase.

For example, in 2018, I missed a large tornado in northern Kansas because I failed to run through the entire checklist:

Anatomy of a Chase Bust - Missing the Tescott Tornado

May 1, 2018 was one of the most painful misses of my chase career. Honestly, I would love to forget this one. But I re-learned two valuable lessons that may help someone else. Here's how it went down:

Image: Sean Ramsey pic.twitter.com/tyR14A7S1l

— Gabe Garfield (@WxGabe) November 3, 2023

In this case, I forgot about "the cap" when I left the messy northern storm for a better-looking supercell to the south.  If I'd run through the entire process, I would have remembered to be very careful about venturing south.

ANNOUNCEMENTS

Speaking of process, I am happy to announce that I'm creating a comprehensive course to teach storm chasing.  To be clear, it will not be another YouTube video short course.  Rather, it will be a full A to Z on how to chase, including all the secrets I've learned in 25 years of storm chasing. Stay tuned for details!

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Well, that's all for now.  Hope you enjoyed it!

- Gabe Garfield

WxGabe on X/YouTube/Facebook/Instagram