El Reno Oklahoma tornado downgraded to EF3

[Kent Heiderich]

It sounds like more information is coming out on this storm from Dr. Howie Bluestein. All KFOR tv (OKC) reported this evening 9-20-2013 is that he increased the tornado circulation to 4.3 miles wide. There were other reference to the May 3, 1999 Mulhall, OK tornado circulation being 4 miles wide. Maybe someone more in the "know" can enlighten us on what is going on or being discussed among the top scientist for severe weather.

 

[rdale]

His research is being released at the AMS Radar convention this week.

 

[Bob Hartig]

I didn't know that about Mulhall. I had read that following the Greensburg tornado, radar indicated tornado-intensity circulation that was four miles wide at cloud level, but one could only speculate whether that extended to the surface. I look forward to reading about the results of Howard et al's findings re El Reno.

 

[rdale]

KFOR tv (OKC) reported this evening 9-20-2013 is that he increased the tornado circulation to 4.3 miles wide.

I missed this the first time... To be clear, KFOR is incorrect. Wrong. Making up stuff for the sensationalism. There is no such thing as a 4.3 mile wide tornado, and Dr Wurman did not claim that one existed. Supertornadoes are not real. This was not 12 times stronger than Joplin.

Mr Morgan didn't understand what he was reading, and instead of asking for clarification just decided to spew it out. And he was completely wrong.

 

[rdale]

http://gabrielgarfield.wordpress.com/2013/09/20/clarification-of-el-reno-tornado-width-claim/

Paper: http://journals.ametsoc.org/doi/pdf/10.1175/BAMS-D-13-00221.1

 

[Kent Heiderich]

Bob we all are awaiting the results of these meetings. I hope we get better radar somewhere along the line, & perhaps the thing I would like to see is a com truck that could link all the chasers to very high speed data. This com truck would tag along to the more high risk areas & provide a strong data signal to the chasers/scientist there. I dream of a "air traffic control" that could warn chasers of impending storm path & know everyones location by GPS. Just saying attack the storm as a group & not as a individual.

 

[Kent Heiderich]

Thanks for researching this rdale. That is why I asked for help on this matter. I do hope chasers can get better info as described in my above post. Seems that is the key to keep everyone safe & yet get good data on a storm.

 

[Bob Hartig]

http://gabrielgarfield.wordpress.com/2013/09/20/clarification-of-el-reno-tornado-width-claim/

Paper: http://journals.ametsoc.org/doi/pdf/10.1175/BAMS-D-13-00221.1

Thanks for that, Rob.

 

[Shawn Schuman]

I missed this the first time... To be clear, KFOR is incorrect. Wrong. Making up stuff for the sensationalism. There is no such thing as a 4.3 mile wide tornado, and Dr Wurman did not claim that one existed. Supertornadoes are not real. This was not 12 times stronger than Joplin.

Mr Morgan didn't understand what he was reading, and instead of asking for clarification just decided to spew it out. And he was completely wrong.

I assume the "4.3 mile wide tornado" came from Dr. Wurman's research on the 5/3/99 Mulhall tornado?

Diagnosed Three-Dimensional Axisymmetric Structure Of The Mulhall Tornado On 3 May 1999.

Edit: Nevermind, just skimmed the paper Rob posted and see where the confusion happened. It's interesting how similar these results appear to the Mulhall study, at least at first glance. I can't wait to read through it in the morning, thanks for sharing.

 

[Brian R]

I really do not agree with the NWS downgrading the El Reno tornado to an ef-3. I was there and this thing was a beast no matter how you look at it, to remove the hood from my chevrolet suburban and make the hood hinges look like twisted metal is not something to take lightly, plus you have doppler radar indicating wind speeds in excess of 295 mph…I really do not see how they can get away with downgrading it but since they are part of the government or government funded I can see how they get their way. Just hoping that some of Team Twistex's research paid off and makes a better early warning system possible.

 

[Dan Robinson]

Sorry to resurrect such an old thread, but I've had a question I haven't yet seen answered. Some who have tipped a cap to the EF3 side of things have used the argument that the 296mph peak wind speeds would have only impacted a given spot for 1/2 second. However, the threshold for EF5 is 205mph, a value which one would assume would have been present for a longer duration and across a broader swath than the 296mph peaks. Is it known from the available data how long the 205mph+ contour values would have been over a given point? I've never seen this discussed anywhere.

 

[Paul Knightley]

I guess as it's a damage intensity scale it would depend on what kind of damage a 296mph wind lasting for 1/2 second would do. The issue here, I believe, is using a scale which was invented based on assessing tornadic damage, and then trying to apply it to wind velocities which have been measured by remote sensing. In almost all cases of tornadic damage which has been assigned an (E)F rating, there was no available wind velocity data, so the rating was based on assumptions. The question for the meteorological community is how to reconcile this difference in 'measurement', if at all.

 

[rdale]

That's what is being addressed now (later this month actually.) The easiest way to answer is that we don't haven't measure the wind speeds needed to knock down every type of building out there. And we probably never will. But modeling will help and with time the scale continues to improve...

 

[Shane Adams]

Sorry to resurrect such an old thread, but I've had a question I haven't yet seen answered. Some who have tipped a cap to the EF3 side of things have used the argument that the 296mph peak wind speeds would have only impacted a given spot for 1/2 second. However, the threshold for EF5 is 205mph, a value which one would assume would have been present for a longer duration and across a broader swath than the 296mph peaks. Is it known from the available data how long the 205mph+ contour values would have been over a given point? I've never seen this discussed anywhere.

All I can offer is, officially (unless I'm mistaken), the threshold for a EF rating is a top gust of at least 3 seconds within that EF rating's wind parameter. If a 1/2 second gust of 296mph was documented, it doesn't sound like much of a stretch to say there was probably a 205+ gust for at least three seconds, somewhere along the path. That would make it an EF5.

 

[Drew Terril]

Shane is correct in that it's derived from an estimate of a 3 second gust based on the damage indicators. I believe 200mph and up is the threshold for EF5, and, like Shane has stated, it's very likely that there was a sustained 3 second gust of 200mph or greater within the time period surrounding the 296mph reading.

That said, until the NWS changes their criteria to include doppler measurements, they will always go off the damage. In an open field, it can be much more subjective unless the storm is moving slowly enough to scour the ground extensively. At it's peak intensity, the tornado had a forward motion in the neighborhood of 55mph, which minimizes the time that the winds are impacting the same section of soil.