Tupelo Tornado Lofts Debris Miles High [RADAR]

A large “wedge” tornado struck Tupelo, Miss. on Monday afternoon. The tornado was spotted from a towercam from WTVA-TV before the internet stream I was watching failed.

This image from the computer program GR2Analyst was tweeted to me by @WxChaser_:

The column of "cool colors" depicts debris lofted four miles high from the Tupelo tornado. (@WxChaser_)

The column of “cool colors” depicts debris lofted four miles high from the Tupelo tornado. (@WxChaser_)

It’s a truly astounding image and is relatively new in Doppler radar technology. This isn’t a traditional radar image depicting rainfall or even wind within a storm. We’ve had that for years.

But in this fairly-new dual-polarization radar product — called correlation coefficient — the radar determines whether the objects being detected by each radar pulse are “similar” in general shape or orientation to the other objects seen by other pulses tiny fractions of a second apart.

The warm colors indicate rain, hail or snow in the cloud–  there’s not much change in their shape or orientation between radar pulses. And that’s what you’d typically find in a thunderstorm.

However, in that column of cool colors, the objects — as meteorologists put it — are not “well-correlated.”

In plainspeak, within that column that stretches more than 20,000 feet into the atmosphere, the radar is telling us that it’s seeing objects of all shapes and sizes.

Things of different shapes and sizes are not supposed to be four miles up in a thunderstorm.

That can only mean one thing — debris from the earth has been lofted by the tornado miles into the atmosphere. Truly terrifying.

That’s the tornado debris signature and actually an indication of the shape and size of the tornado itself.

In fact, the tornado column and the parent supercell thunderstorm are “tilted” in response to increasing upper-level winds the higher you go into the sky.

Now, we don’t have to “slice” the storm to get a view of a tornado debris signature.

This is how the correlation coefficient product looked about the same time. You can clearly see the spot of blue — the area where the radar is detecting debris, and thus, the tornado itself.

The so-called “debris ball.”

An area of poorly-correlated radar echoes associated with the Tupelo tornado.

An area of poorly-correlated radar echoes associated with the Tupelo tornado.

Meteorologists don’t need no stinkin scripts!

It’s funny. Just last night, someone I just met mentioned to me something to the effect that all of us who are on TV are reading words on the prompter.

Not so fast!

It’s true that news anchors do read many of the news stories from the prompter, but everything we weather folk say on TV is right off-the-cuff.






In fact, I specialized in extemporaneous speaking on my high school speech/debate team.

It was a great preparation for live television.

We’d all be in an auditorium and draw a slip of paper which gave us the time of day we’d give our six-minute (or so) speech about a current events topic.

When we’d be about 30 minutes out from the time of our address, we’d draw a topic and have only that half-hour to go through our bins of newspaper clippings (yeah, before the internet, remember that?) and study up.

We had to obviously, spend hours clipping articles out of periodicals and file them away before a tournament.

Kosovo. Apartheid. The fall of the Eastern bloc. Our teenaged fingers would be covered in newsprint by the end of a clipping session.

Anyway, back to the auditorium. When our 30 minutes were up, we’d walk into a classroom in the school in front of three judges and give our speech (sometimes allowed one index card for notes, often not allowed any reference help).

The judges were generally knowledgable about current events, so if you didn’t have a grasp on your topic, there was no making it up!

Doing extemporaneous speaking — or “extemp” as it’s known in forensics — was outstanding training for what I do every day.

I do all the research I can, I know my material. Just now in my old age, I’m given hours to prepare my forecast and just deliver two or three minutes on-air! But there are those times when weather is breaking news, and we’re off.

(News anchors also go “off-prompter” when big news is happening, and I work with folks who are the best in the business at keeping coverage going.)