May 21, 2011 Ada, Oklahoma Tornado: Tornado Video, Chase Logs and Images and Rocky's Storm Chaser Picnic

or The Most Cooperative Tornado

 


YouTube Video of Tornado (Original is in HD Video)

 

chase images and log by William T. Hark, M.D. Video (HD) and pictures available for licensing

 


 

I was chasing with Dave Lewison along with Scott McPartland and Canadians, Mark Robinson, Brad Rousseau, Meghan Yeo, Dayna Vettese and Heather Reynolds. Chris Kridler had already decided to chase in the Ardmore area. Jason and Robert stayed in Wichita the previous evening and Jason hit a deer near the city. Luckily, he was not injured but had to spend part of the day changing rental cars. I started in Enid, Oklahoma and had initially planned on not chasing and just going to Rocky's picnic. Every year, Rocky Rascovic has a big storm chaser picnic at his farm just northwest of Oklahoma City in Piedmont. The party is moved to the next weekend if severe weather is predicted for the day of the party. Saturday, May 21, initially appeared to be so marginal that the picnic was given a “go ahead” on Friday. On Saturday, the day of the party, the chasing prospects had improved slightly but were still poor. There was a closed low over southwestern South Dakota and 40 kt winds over southern Oklahoma that were expected to increase. At the surface, the winds were weak but from the south to southeast in southwestern Oklahoma and eastern Kansas . Expected dewpoints would be in the low 60's. CAPE, according to the NAM. would reach 2500 to 3000 J kg-1 by evening in eastern Oklahoma. Storms could form along the dryline as it shifted eastward. The most interesting model outlook was the 22hr WRF showing an isolated cell in south central Oklahoma. Unfortunately, the models showed expected 850 mb winds from the southwest. Generally, veered 850 mb winds don't produce photogenic tornadoes. The SPC did issue a slight risk for eastern Oklahoma and southeastern Kansas. (5% tornado risk). Some chasers blew off the picnic to chase or were out of range to attend. Others planned on attending the party and not chase. After reviewing data, we then had the difficult decision of chasing vs attending Rocky's party. We also had to consider getting in position for Sunday. There were two possible Saturday targets: northeastern Kansas and southeastern Oklahoma. The Kansas target was away from both the party and a potential target on Sunday. Finally we decided to head south, stop by Rocky's house, and monitor the situation to our south. Rocky and his family had already purchased the food and had spent a lot of time setting up for the party. Our tentative target was a diffuse area from Ada to Ardmore, Oklahoma. We had a great time at Rocky's and stayed a bit too long chatting, eating, checking out the storm shelter and playing with the multitude of dogs, cats and horses. Attendance was lower than usual but we enjoyed seeing a lot of friends and meeting new chasers. We also monitored weather data from his house.


Watching tornado video at
Rocky's storm chaser picnic

Way too much good food


Monitoring weather data at
Rocky's party

Brad Rousseau and the dog



Mark Robinson checking out Rocky's
storm cellar

By late in the afternoon, there were signs of development southwest of Oklahoma City near Ada. A distant storm was visible poking over the horizon. After some delay, we left the party at 6PM. It was like a scene from Twister where storm chasers have a relaxing dinner and then blast out to chase a storm. From the farm in Piedmont, we cut across some back roads and eventually turned south on I-35. The storm was rapidly intensifying. From a distance, the storm had a beautiful crisp updraft. Chris Kridler, who blew off the party to chase, reported a rotating wall cloud on the initial storm and later brief tornadoes. We were concerned that we would arrive too late. We were 4 miles from Purcell by 7:08 PM. As we vectored toward Ada, Oklahoma, there was some additional development to the north of the main storm. Near Ada, a storm the north of the initial storm was showing signs of rotation while the southern storm was dying. It was 8:04 PM. Since we were closer to the northern storm, we decided to intercept that storm rather than going after the initial storm. We drove toward Ada, then west on 19. Road options were limited. Although one usually targets the southern storm, in this case, the southern or initial storm was rapidly weakening. West of Ada, we got an amazing view of the updraft and inflow bands through the trees. Our group stopped at the unincorporated town of Gaar Corner at 8:15 PM and watched the storm to our west. There was a large inflow band from the north and rotation to our west along with a bowl-shaped lowering. We observed a few needle funnels by 8:23 PM and more rapid rotation of the entire mesocyclone. There was a report of a multivortex tornado but nothing was visible due to a line of trees. At 8:24PM, we shifted back east to get out of the precipitation. We stopped after a brief spinup was observed and were able to see a cone tornado form and cross the road to our west. The tornado nicely formed between trees on both sides of 19 at 8:31PM and lifted by 8:33 PM. It was a most cooperative tornado! A guy in a truck pulled off by our position, asked a few question and roared off toward the tornado. The driver said he was checking on his family. Although brief, the tornado was beautiful as it was silhouetted against a yellow-orange sky. We headed east. I could see a ragged wall cloud to the northwest at 8:37 PM but no tornado. At 8:38, there was a slight funnel but but unclear if there was a tornado. We turned northwest on 3W watching the storm cross that road. At 8:48 PM, there may have been another brief tornado but visibility was poor. As it was getting dark, the chase ended, and we had the traditional celebratory steak dinner at the Ada Applebees. The entire restaurant was filled with successful and happy chasers (30 or 40?) and we had a fun time talking and comparing videos and experiences. After dinner, we headed to Ardmore for the night.

May 21, 2011 is one of my favorite chase days. Rarely does one have a relaxing afternoon hanging out with other chasers at a party, have a short drive to the target, see a beautiful tornado that does little damage and no injuries and end the day with a steak dinner at a chaser convergence.


Storm on the horizon, viewed from
near Rocky's house, 6:02 PM CDT

Zoomed view of storm, 6:10 PM

Approaching storms near Ada,
7:25 PM

Supercell at sunset, 8:08 PM, view
from 19, west of Ada

Supercell at sunset, 8:10 PM, view
from 19, west of Ada

8:12 PM CDT


ThreatNet radar image, time 8:15 PM
Our position is the white spot in circle

8:16 PM

GrLevel 3 radar image 8:18PM

Rotation increasing, 8:18 PM
view from Gaar Corner on 19

Big inflow feature, 8:19 PM
view from Gaar Corner on 19

Looking west on 19 at 8:30PM
just before tornado

Tornado, 8:31 PM

Suction vortex with tornado

8:31 PM CDT. The tornado is
nicely between the trees

8:32 PM

Tornado is starting to lift
at 8:33 PM

Local man races off to
check on his family at 8:33 PM

Scott McPartland watching the storm
at 8;34 PM CDT

Heading east on 19, view is back
to the northwest at 8:38PM

Tornado-warned storm at 8:44 PM

Threat Net radar image at
8:47 PM

Storm to the north at 8:47PM and
possible tornado is visible on video

Celebratory steak dinner at the
Ada, Oklahoma Applebees

Jim Leonard and some of
Extreme Tornado Tours participants


Scott McPatland teaching some kids
about tornadoes and showing video

Archived Outlooks, Weather and Model data

Convective Outlooks: 12Z,1630Z,2000Z Tornado Watch Prelim Storm Reports Storm Data: #1,#2,#3
250 mb: 12Z, 00Z 500 mb: 12Z, 00Z 850 mb: 12Z, 00Z Surface Obs: 1423Z,00Z
Satellite 1402Z 12Z NAM 850mb 1800Z 12Z NAM 850mb 0000Z 12Z NAM 850mb 0600Z
12Z NAM Surface Wind/MSLP 1800Z 12Z NAM Surface Wind/MSLP 0000Z 12Z NAM Surface Wind/MSLP 0600Z 12Z NAM 700 mb Heights/Temp 0000Z
12Z NAM Surf temp/dew 1800Z 12Z NAM Surf temp/dew 0000Z 12Z NAM CAPE 1800Z 12Z NAM CAPE 0000Z
12Z NAM Precip 0000Z 13 Z RUC Surface Wind/MSLP 1900Z 13 Z RUC Surface Wind/MSLP 2200Z 13 Z RUC SRH 2200Z
13 Z RUC CAPE 2200Z 13 Z RUC Precip 2200Z 13 Z RUC Precip 0100Z and CAPE WRF Reflectivity 20 hr,22 hr,23 hr, 24 hr,25 hr


Go to May 22, 2011 Storm Chase

All images Copyright 2011 William T. Hark