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Plains tornado threat Mon 5/27-Fri 5/31

tornadotony

By tornadotony,
in Central/Western States

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AtticaFanatica

AtticaFanatica

Posted
Posted

There were at least two research teams out yesterday (DOWs and an OU team), pretty good chance there were more, hearing some crazy velocities were sampled (> 100 m/s).

That's good to know. The couplet looked extremely intense so I've been really curious about what kind of velocities were pulled out of it, and if we are talking greater than 100 m/s then that's legit.

Also, back with El Reno in 2011 there was a big issue about rating the tornado based off of wind speed measurements, and now the Rozel tornado was based off of measurements, so has that become acceptable for EF rating? I remember that you were privy to the conversations back in 2011, and I was just wondering what has changed since then.

Yes, winds of at least 116 m/s were sampled close to the ground by RaXPol. Those numbers, in part, were used to bump it to EF5. There was some hand-wringing and a directive to not use mobile radar data in ratings anymore. As far as I know, that's where we stand.

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tornadotony

tornadotony

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Yes, winds of at least 116 m/s were sampled close to the ground by RaXPol. Those numbers, in part, were used to bump it to EF5. There was some hand-wringing and a directive to not use mobile radar data in ratings anymore. As far as I know, that's where we stand.

Was that an SRH directive or an NWS-wide directive?  B/c if it's an NWS-wide directive, it's already been violated 3 times in the past couple of week.

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nwburbschaser

nwburbschaser

Posted
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Yes, winds of at least 116 m/s were sampled close to the ground by RaXPol. Those numbers, in part, were used to bump it to EF5. There was some hand-wringing and a directive to not use mobile radar data in ratings anymore. As far as I know, that's where we stand.

Unless I am misunderstanding how the rating came about, Rozel on 5/18/13 was rated an EF-4 based on the DOW.  There wasn't all that much damage from it and when it came out as en EF-4 I was surprised, and then read about the DOW measurements. 

 

Here is the link:

 

http://www.crh.noaa.gov/news/display_cmsstory.php?wfo=ddc&storyid=94702&source=0

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AtticaFanatica

AtticaFanatica

Posted
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Yes, winds of at least 116 m/s were sampled close to the ground by RaXPol. Those numbers, in part, were used to bump it to EF5. There was some hand-wringing and a directive to not use mobile radar data in ratings anymore. As far as I know, that's where we stand.

Was that an SRH directive or an NWS-wide directive? B/c if it's an NWS-wide directive, it's already been violated 3 times in the past couple of week.

I thought it was the latter, which is why I'm confused as well.

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AtticaFanatica

AtticaFanatica

Posted
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Yes, winds of at least 116 m/s were sampled close to the ground by RaXPol. Those numbers, in part, were used to bump it to EF5. There was some hand-wringing and a directive to not use mobile radar data in ratings anymore. As far as I know, that's where we stand.

Unless I am misunderstanding how the rating came about, Rozel on 5/18/13 was rated an EF-4 based on the DOW. There wasn't all that much damage from it and when it came out as en EF-4 I was surprised, and then read about the DOW measurements.

Here is the link:

http://www.crh.noaa.gov/news/display_cmsstory.php?wfo=ddc&storyid=94702&source=0

Thanks, heard that, but hadn't read the link. It's possible there was a change of heart or just confusion on the part of some WFOs.

It's a somewhat controversial topic. I have my opinions, but they're pretty biased, admittedly.

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Chinook

Chinook

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Any recep of yesterdays Tornadoes yet? Looks like death toll is up to 9. =(

I saw a preliminary map of three approximate tornado paths on the NWS OUN web page. This map was made before the storm survey. The storm survey crews may be out there right now.

 

Look at this Norman OK sounding that was very near the tornadic storms last night. The data cuts off at 250mb, so the CAPE values shown only use temp. data to 250mb. I believe the MUCAPE could have been over 4600 J/kg (that is 3646+1000 J/kg) if there was complete temperature data to high altitudes. If so, then SCP would have been 37.

 

3km helicity=400 m2/s2

0-6 km shear = 56 kt

 

post-1182-0-70008300-1370117193_thumb.gi

 

 

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AtticaFanatica

AtticaFanatica

Posted
Posted
There were at least two research teams out yesterday (DOWs and an OU team), pretty good chance there were more, hearing some crazy velocities were sampled (> 100 m/s).

Update: Sounds like there was VORTEX2-type radar coverage on yesterday's supercell. DOWs, 3 OU groups, Tech, NSSL all were on it. Good news.

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Ensō

Ensō

Posted
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Update: Sounds like there was VORTEX2-type radar coverage on yesterday's supercell. DOWs, 3 OU groups, Tech, NSSL all were on it. Good news.

 

Nice, I got a brief glimpse of what looked like a DOW on one of the chaser streams yesterday but I wasn't sure. I'm sure they got one hell of a data set.

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Chinook

Chinook

Posted
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NWS Norman tweets

 

NEW: SW OKC Tornado. EF1. 10.4 mile path from SW 15th and Morgan Rd across Will Rogers Airport to near I240 and Western

 

Today's surveys are more complicated than last week's. We can confirm at least five tornadoes, and there will probably be more.

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Derecho!

Derecho!

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So thats 3 sigtors and all were embedded in a squall line! Will make an interesting case study.

 

 

The two EF3s were the same "cell" and I would guess the path of the first one might be extended at some point (based on what LSX said) so they are the same one on both sides of the Mississippi.

 

I have a feeling that EF2+ QLCS tornadoes aren't all THAT rare. Certainly not common, though. 

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Hoosier

Hoosier

Posted
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The two EF3s were the same "cell" and I would guess the path of the first one might be extended at some point (based on what LSX said) so they are the same one on both sides of the Mississippi.

I have a feeling that EF2+ QLCS tornadoes aren't all THAT rare. Certainly not common, though.

Here's a good read that compares supercell and QLCS tornado strength, although it only covers a 3 year period. There were some F3-F4 QLCS tornadoes during the period of study:

http://journals.ametsoc.org/doi/pdf/10.1175/WAF-835.1

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cmichweather

cmichweather

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Yes, winds of at least 116 m/s were sampled close to the ground by RaXPol. Those numbers, in part, were used to bump it to EF5. There was some hand-wringing and a directive to not use mobile radar data in ratings anymore. As far as I know, that's where we stand.

I've long thought that mobile obs would confirm that the F-Scale was pretty close to what was reality, That was a monster storm but the 20th was probably stronger. Either way I think the worst part of trying to classify storm based on damage is the frictional drag imposed on the storm you could easily lose a good deal due to the drag based on construction vs. an open field. 

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Superstorm93

Superstorm93

Posted
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I now know of two separate radar teams that have unofficial radial velocity observations over 110 m/s in the El Reno tornado.

I could actually believe that the 2013 El Reno tornado had winds of about 100–110 m/s. The velocities from TOKC and TLX were just about the strongest ever recorded from a WSR–88D and TDR

I'd be surprised if it wasn't upped to EF5 status

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thunderbird12

thunderbird12

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Probably one of the strongest mesocyclones ever observed by radar. Whether or not it fully consolidated into something of EF4/5 strength is unclear. If it did, it probably didn't last in that state for very long and would have been in mainly rural areas at peak intensity. The extreme radar velocities may have been as much a reflection of the unusual size of the circulation (since more of it would be fully resolved) as the peak intensity. It will be interesting to see the final survey results and any data that was collected from mobile radars.

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thunderbird12

thunderbird12

Posted
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It appears that at least 11 people drowned in OKC on Friday night while seeking shelter from tornadoes in drainage ditches. There are conflicting reports about how many bodies have been recovered as of now, but all 11 (including 7 from one family) are presumed drowned:

 

http://newsok.com/three-storm-chasers-among-victims-of-oklahoma-storms-three-more-bodies-found-sunday-as-death-count-rises-to-13/article/3841107

 

http://www.koco.com/news/oklahomanews/okc/deputy-fire-chief-confirms-2-ongoing-searchandrecovery-missions/-/11777584/20393174/-/v7f2oez/-/index.html

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Superstorm93

Superstorm93

Posted
Posted

Hate to be that guy

 

But if any red tags or pro forecasters have any info on DOW recorded wind speeds during the El Reno tornado I would greatly appreciate it if you could PM me whatever you have at this point. 

 

I'm in the middle of doing some research and obviously any info on early wind estimates would be welcomed. 

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JoMo

JoMo

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It appears that at least 11 people drowned in OKC on Friday night while seeking shelter from tornadoes in drainage ditches. There are conflicting reports about how many bodies have been recovered as of now, but all 11 (including 7 from one family) are presumed drowned:

 

http://newsok.com/three-storm-chasers-among-victims-of-oklahoma-storms-three-more-bodies-found-sunday-as-death-count-rises-to-13/article/3841107

 

http://www.koco.com/news/oklahomanews/okc/deputy-fire-chief-confirms-2-ongoing-searchandrecovery-missions/-/11777584/20393174/-/v7f2oez/-/index.html

 

16 now. From the top article:

 

"The families were worried about the storm and were afraid of the tornadoes, especially after the EF5 tornado that struck May 20. The seven left home and sought shelter above a drainage canal, then were swept away when the high waters came, he said."

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wxsniss

wxsniss

Posted
Posted

Hate to be that guy

 

But if any red tags or pro forecasters have any info on DOW recorded wind speeds during the El Reno tornado I would greatly appreciate it if you could PM me whatever you have at this point. 

 

I'm in the middle of doing some research and obviously any info on early wind estimates would be welcomed. 

 

Along these lines...

 

Is there an established conversion of g2g velocities to max wind speeds?

I imagine this must factor in distance of radar beam (height) as well as diameter of the couplet... just curious about the 290+ kt g2g couplet we all posted near El Rino... TIA

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