Scientists Confirm 300+ MPH Winds in Greenfield Tornado!

July 2024

Hello, Friend!  Hope you're enjoying the weekend.

After an amazing severe weather season, we're finally enjoying some quiet in the Plains. So there's no better time to look back at one of the most intense tornadoes of the year!

GREENFIELD TORNADO MAX WINDS

Recently, the Center for Severe Weather Research confirmed that the EF4 Greenfield, Iowa tornado had some of the most intense winds ever observed. Based on Doppler on Wheels (DOWs) data, they estimate that the tornado contained winds of 309-318 mph!

As the 2024 #BEST field season ends, a glimpse into the data collection during the Greenfield, IA tornado. Peak wind speeds as high as 309-318 mph were calculated in a narrow region 100-160 feet ARL. These are among the highest wind speeds ever determined using DOW data. https://t.co/CM09J3VSOB pic.twitter.com/fuxfdyoi9d

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

These winds were measured near th...

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 g

...

I’ve chased tornadoes for almost 25 years.  And in that time, only one has ever chased me.

It was, of course, the El Reno, OK tornado of 5/31/13. It was 2.6 miles at its widest, had winds > 300 mph, and moved faster than 50 mph. 

I’ve chased tornadoes for almost 25 years. And in that time, only one has ever chased me.

It was, of course, the El Reno, OK tornado of 5/31/13.

It was 2.6 miles at its widest, had winds > 300 mph, and moved faster than 50 mph.

For the first time, here is my full story:

1/25 pic.twitter.com/7xuCcugP6L

— Gabe Garfield (@WxGabe) February 11, 2024

To be honest, I really wasn't aware of how volatile it looked until it came. Reason being, the weather had been crazy. I'd been chasing more than a half-dozen times since May 18th. And frankly, I was exhausted. I wasn't very interested in forecasting.

But the day had arrived, and there was a lot of hype. So, obviously, I had to take a closer look. Extreme instability was a given over C OK. But the models now for...

Eleven years ago ago today, I had the most horrifying chase of my life.

That morning, I woke up late, in anticipation of a late start to my work day at the National Weather Center. Since it was a weekday, I wasn’t planning on chasing. Out of curiosity, though, I thought I would check out the forecast. While waiting for my computer to boot, I went outside to get a feel for the weather. It was sunny – but cool – and stratocumulus clouds were racing northward with the low-level jet. It just had the “feel” of a big day (most folks who have spent significant time in Tornado Alley know what I mean).

I went back inside to check out the forecast. After going through the usual parameter checking, I perused a few convection-allowing models (weather models that predict actual thunderstorms). An ominous forecast was projected: supercell thunderstorms would develop in central Oklahoma by mid-afternoon. I became increasingly concerned about the possibility of a significant tornado not far from Nor...

This has been an absolutely crazy week or so, hasn't it?  And it looks like we're just getting started!

Check out Tomer Burg's animation of the last week's storm reports!

A quick look at SPC storm reports from the highly active - and unfortunately devastating - stretch of severe weather over the last week that is still ongoing: pic.twitter.com/YuyQWctk34

— Tomer Burg (@burgwx) May 4, 2024

THE YEAR OF THE TORNADO

Over the last several months, meteorologists had been suggesting that 2024 would be a big tornado year.  A lot was made of the impact of high sea-surface temperatures in the Western Gulf of Mexico and the transition from El Nino to La Nina.

But as March rolled into April, below normal tornado activity continued. Several big events occurred, but photogenic tornadoes were few and far between.

One exception was a local outbreak of tornadoes that struck Iowa on April 16th. Paul Spomer caught this amazing, sinuous tornado just north of the surface low:

CAREER DAY in No

...

May 3, 1999. 

To those outside of Oklahoma, this date means very little.  But to those Okies who survived the largest tornado outbreak in state history, “May 3^rd” is forever branded into our collective conscious. 

That day over 60 tornadoes swept across the Southern Plains, with the vast majority in central Oklahoma.  Many of the tornadoes were strong, and at least 4 were violent (F4/F5).

Most people remember the Bridge Creek / Moore tornado, which until 2013 held the world record for highest wind speed on Earth (~300 mph).   That tornado lasted well over an hour, and claimed the lives of over 30 people.  Interestingly, that tornado was really only the beginning of the outbreak, as many more tornadoes occurred well after dark. 

The most impressive of these was the Mulhall tornado, which was well over a mile in diameter; based on mobile radar data, it may have been more intense than the Moore tornado.  The following is my story from that day.

It was early May in 1999, and I was f...

Sometimes, it's hard to remember how you began.

And that's definitely true for long-time chasers. We sometimes forget how hard it was for us in the beginning. And when I started, I was really bad at it.  So I thought it might be helpful to tell how I became a chaser

For me, it all began in 1990. On May 15th, a powerful F3 tornado struck my hometown, Stillwater, OK.

After the tornado hit, I became fascinated with tornadoes. Trouble was, I didn't know where to find information about them. My mom suggested that I write the local weatherman, Gary England,  to see if he might be taking his tornado safety talk to town.

To my surprise, Gary wrote back. His letter arrived 3 weeks after I sent mine. He said that, sadly, he wouldn't be coming to Stillwater that year. But he gave me a copy of his book "Those Terrible Twisters and the Weather of Oklahoma"

That was when my obsession truly began. The book that Gary gave me had it all: tornado pics, dates, locations -- everything. I liter...

Introduction

Welcome to my new blog. Periodically, I will be posting about weather events I find interesting.  I'll also be adding chaser-relevant bits I learn from science articles.  Hope you enjoy!

Basic Meteorology for Storm Chasers

I recorded a new version of the beginner's meteorology presentation I gave at NSCS.  In it, I cover:

• Surface maps
• Upper air maps
• Skew-T Log-p charts
• Hodographs

You can find it on Youtube here.

And if you find it useful, please like and subscribe!  I'll be posting more content like this soon.

Storm Mergers

Also, I've been reading quite a bit of research on storm mergers and their relationship to tornadogenesis.  It turns out that mergers matter -- a lot.

Did you know that 50% of tornadoes form within a few minutes of a merger?  This is not an accident. It turns that mergers are important because they increase stretching. 

(Y'all remember the ice skater analogy, right?  Spin and stretch!)

Also, it turns out that a lot of merging cells...