Wednesday, June 5, 2013

What Happened on May 29, 2013 ?

For the last couple of day’s,  I’ve been writhing about the dangers of storm chasing. Well to be honest, I’ve been writhing about the dangers of storm chasing for the uneducated for as long as I’ve been writhing in this blog, one only has to go back to some of the earliest post to see that. The infusion of chaser wannabees has gotten so far out of hand , that it’s now an epidemic. The sheer number of chasers converging on a single storm can be over one hundred. I will come back to this point later in the post.  
A few days before the severe event on the 29th, the Storm Protection center (SPC), many weather outlets, and my weather page, were putting out the word, that a big severe outbreak was going to hit the Plains and Midwest. On the morning of the 29th, I drew a map that highlighted the area around I-35 and I-40 near Oklahoma City and how 5:00 to 7:00 pm would be the time Oklahoma City would have to be on guard; because the setup was such, that large dangerous violent  tornadoes were quite possible. I also talked about how the severe weather would move into Missouri and Illinois, later in the night.

So even though I knew the setup was off the chart; the reality of what I saw late in the afternoon and evening of the 29th, was awe-inspiring and unbelievable.

Jeff Snyder

A picture of the El Reno – New Castle tornado  Image credit Jeff Snyder.

Here is a brief  timeline for the area around Oklahoma City and the NWS Norman.

7:45 AM The NWS Norman releases their first public briefing , alerting of the chances for Severe weather which would include giant hail, destructive winds, tornadoes (some of which could be violent), and flash flooding..... especially for Oklahoma City (OKC), El Reno, and Moore.

2:29pm - The results of the 1pm special balloon launch were in. The sounding showed that the cap was still in place, but moisture had increased considerably in the lowest levels since the morning balloon launch.

4:35pm - The storms were developing rapidly from Kay, eastern Garfield, Kingfisher, Blaine, NE Caddo and E Washita counties.

4:45pm - Severe thunderstorm warnings were going up for storms near Ponca City and in west central Oklahoma.

By 5:00pm - The cold front extended from eastern Kansas southwestward into northern Oklahoma and down into the Texas Panhandle, along with a dryline stretching Through western Oklahoma and western Texas. Around OKC dew-points were in the mid 70's to low 80's with temperature in the 90's. The MLCAPE values were 4000-5000 J/kg. Hodographs were showing a strengthening low level jet, which was providing plenty of upper level shear. Needless to say the atmosphere was extremely unstable. Conditions were ripe for rapid intensification.

520pm - Storms started to explode on radar and quickly went severe and developed into clusters. Within minutes the storms were rotating and some even had the first signs of hooks developing.

Tornado warnings were going up west of OKC.

5:43pm - NWS Norman was warning motorist on I-40 to not drive west past West OKC due to dangerous storms over I-40

5:53pm - The storm along I-40 in Canadian County had a lot of rotation on it, but no confirmation of a tornado !!

5:54pm - People on the ground reported a large tornado very near I-40

5:55pm - Norman issued the warning that a rain-wrapped tornado was 2 to 3 miles south of I-40, southwest of El Reno! The NWS warned people to take cover. This is the beginning of the El Reno – New Castle tornado. Which would end up being one of the most powerful tornadoes on record.

6:03pm - The tornado was about 2 miles south of I-40 near El Reno. Norman was urging people in El Reno to take cover.

6:21pm - NWS Norman alerted that a large violent tornado was moving along and just south of I-40 near El Reno. Warning that this was deadly serious situation! Telling people in Mustang, Yukon and Union City to take cover immediately.

6:25pm - A tornado emergency was issued for Canadian County

6:37pm - Many supercells are moving over Oklahoma. The most dangerous one was over Canadian County already had a history of producing tornadoes. This was beginning to move into OKC metro

6:43pm - The El Reno-New Castle tornado lifts, after carving a path for 16.2 miles.

6:56pm - New tornado warnings were going up for Downtown OKC! Tornadoes continue to move through Mustang, OKC, Del City, Moore, Blanchard, and Union City.

7:55pm - The NWS warns residents of Norman to prepare for winds of 80-90 mph and that the line could have brief embedded tornadoes! They warn everyone to take tornado precautions .

8:07pm - The NWS is warning of dangerous flooding that is developing OKC Metro. Vehicles are stranded in water. Warning to stay home and stay away from OKC!

8:13pm - The tornado threat was diminishing for Damaging wind threat high ahead of the storm complex moving southeast through OKC metro area. Flash flood threat is getting very serious in metro area!

First responders are responding to people trapped in rising flood waters.

In the course of three hours, five tornadoes leave OKC and its suburbs in shambles with many people dead and many more injured.  

Radar scans:


The El Reno – Union City EF5 tornado.

 The radar images I post here show multiple tornadoes slamming into Oklahoma City


GRlevel 3 radar image showing four tornadoes. The National Weather Service would later determine  there were a total of five tornadoes that hit the Oklahoma City area.

before G2G 190-195

El Reno G2G 190-195 KT

Showing Gate to Gate 185-190kt shear velocity.
Gate-to-Gate shear is the measure of the difference between two opposing velocity signatures that are side by side on a WSR-88D velocity image. The red colors indicate wind moving away from the radar with green colors representing wind moving toward the radar  This is normally used to determine the potential for tornadogenesis,  For instance if two pixels are side by side and one is +65kts for instance, and the other is -70kts. Then you have 135kts of gate to gate shear, and if it's in the lower tilts then you have a pretty good categorical likelihood of a tornado.

    Delta-V is insane
Gate to Gate is well over 230kt.
A GRlevel 2 analysis showing a 3D cross section.
One more radar image that I wanted to show you.
RaxPol data of the El Reno Tornado
Rapid-Scan, X-band, Polarimetric mobile Doppler radar (RaXPol ) showing a satellite vortex around the El Reno – New Castle EF5. I don’t know about you, but I find this image very impressive.

RaXPol was developed by Howie Bluestein for severe research. When in operation it does a full (rotational) scan every 2 seconds (180°/s) and a full volume scan every 20 seconds. Bluestein has said that he figures that a air parcel comes in and goes out of a tornado in about 10 seconds on average and that same parcel can go up ~5km in about 100 seconds.  

How could so many experienced storm chasers and researchers be taken by surprise?    

There are a number of factors that may have contributed to chasers getting caught in EL Reno- New Castle EF5?

1. The tornado formed very quickly and became very violent almost as soon as it hit the ground 

2. Erratic motion of the main tornado: initial motion was Southeast, but then it dove east, then veered slightly southeast. then made a very quick turn to the northeast, before moving back toward the east.  Here is a graphic that shows this motion.

   damage path for the El Reno tornado

I talked about this on my Facebook weather page, where I said, The change in direction along a partial cyclonic loop is fairly rare for major tornadoes. Normally a major tornadoes path is more predictable, if you’re paying attention to storm structure and other clues the storm is giving you.

The tornado was also making very rapid changes in forward speed. A very rapid increase in forward speed, then a rapid decrease, is even more rare than the erratic motion.

Another thing, the tornado  went from 1 mile wide to 2.6 miles wide in around 30 seconds. Think about that for a minute, If you had been 2 miles from the tornado, in a place you thought was safe, the tornadoes rate of expansion would have overwhelmed you faster than you could possibly have acted.

This is most likely the main reason the tornado caught many chasers off-guard and had to focus on fleeing for their lives.   

3. The presence of at least one satellite tornado. Transient spin-ups are common in large tornadoes. But as I showed in the  RaXPol image above, the satellite tornado was major by any standards  

 4. The EF5 on May 20 that hit Moore, OK. Because it was so recent people were understandably very terrified . Add to the fact that certain local TV meteorologist were telling the local populace to attempt to evacuate the area. I can’t say this had anything to do with the initial tornado. But I’m fairly sure it didn’t help, especially further east toward OKC.   

Peggy Willenberg and Melanie Metz (The Twister Sisters), were also west of Oklahoma City on Friday the 29th. Melanie said " We were in a hairy situation , We were under the storm as it blew up immediately to our West. It matured very quickly and as we tried to get south the traffic was totally jammed on all roads going south of I-40. So, we turned around and went East on I-40 to get ahead of it and find another option south. Brad got stuck in the south traffic where we turned around and luckily managed to outrun the wedge. We finally found south and east routes to stay just SE of the storm....but barely....with tons of gridlocked roads and crazy drivers all trying to outrun the storm."

    damage path of the El Reno and south OKC tornadoes

    damage path of the South OKC and tinker AFB  

Tim Samaras and team TWISTEX:

When I was awoken by a phone call, telling me that Tim Samaras, his son photographer Paul Samaras, and meteorologist Carl Young had died in the tornado, I was heartsick , it felt surreal, I'm still in disbelief. The news also ripped open the wound of Andy Gabrielson's passing, last year.

Tim's, Paul's, Carl's, or Andy's deaths make no sense. This kind of thing always seems to happen to the best people.

Tim Samaras was a tornado scientist, engineer, and storm chaser for nearly 30 years. He was the founder and leader of TWISTEX. One of Tim Samaras' most widely recognized contributions to tornado science was his placement of  aerodynamically-designed probes, that would measure the pressure inside a tornado. In fact, one of his probes measured a world-record pressure fall of 100 mb over a 40 second period, in an EF-4 tornado close to Manchester, South Dakota on June 24, 2003.  

Not only was Tim an esteemed scientist who loved the science of meteorology, he was also a nice, fun-loving guy, who was quick with a joke. He loved his family and friends. As a storm chaser he was a legend. When Tim did seminars and talks, he would make time for anyone who asked him a question. Tim, Paul, and Carl were the best at what they did.  

I have seen more than a few on television and in the printed media, Call Tim Samaras a thrill seeking storm chaser.  This kind of talk makes me  furious.   

Anyone who knew Tim Samaras and his team would tell you they weren't thrill seeking, they were doing a job they loved. A job that had to (and still needs to be) done. The work they were doing was to save lives, by increasing our knowledge of tornadoes, thereby increasing warning times.  

There are storm chasers out there who are in it for the thrill and the bragging rights. People who only chase to see a tornado. These kind of chasers are making a bad name for all chasers. These kind of chasers clog the roads.  But Tim and team TWISTEX weren’t one of them. Tim and his team were the most careful and controlled chasers in the business.  

Tim’s brother said “He was just caught up in a very unfortunate situation, where he was tracking a tornado and the tornado turned against him and there was no way he could get out from it,"

My condolences and prayers go to all of the family, friends, and surviving members of team TWISTEX of Tim Samaras, Paul Samaras, and Carl Young. Their deaths are a terrible shock to the meteorological community, the chasing community, and a great loss for tornado science. 

 Jennifer, Amy, Matt,  and Kathy, I'm so sorry for your loss.

Rebecca Ladd

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