June 5, 2009

Statistics:

Initial Target: Sterling, CO
Departure: Westchester, IL 10:00 pm, June 4
Arrival: North Platte, NE 1:00 am, June 6
Intercepts: Harrisburg, NE
Tornadoes: 1
Hail: None
Wind: Non-Severe (not measured)
Features: Tornado, Wall Cloud, Funnel
Miles: 1171

Summary:

Upslope flow setup in Wyoming and Colorado.  Targeted Sterling, CO.  Left Westchester at 10:00 pm solo arriving in Sterling at 2 pm.  Ran north into Nebraska for storms initiating in southeast Wyoming.  Intercepted storm just south of Harrisburg, NE at 4:30 pm noting stovepipe tornado.  Watched tornado rope out from distance and observed storm approach with cycling wall cloud and funnels.  Followed storm until it gusted out at 8 pm east of Dalton, NE.  Celebrated with steak dinner in Sidney, NE with Stan Rose and IL gang.

Crew and Equipment:

Solo chase.  Equipment:  Kenwood TH-F6A Tribander, Dell Inspiron Laptop.  Kyocera data card and router, Holux 236 GPS, Robotic camera dome with Sony XR-520V.

Details:

Friday was the first day in a weekend of chase opportunities.  Conditions looked good for high plains supercells in Colorado and Wyoming with dewpoints in the upper 50's (more than adequate for the 4000 foot elevations) and 30-40 knots of deep layer shear.  High LCL's and weaker low level flow led me to believe this would be more of a structure day than a tornado day.  Given multiple opportunities across the weekend I was able to justify the distances involved in chasing this setup.
 

Ben Leitschuh was originally planning on coming with me for the trip.  However, at the last second he bailed due to plans his girlfriend made.  This meant I would be driving all the way to Colorado by myself.  It being the night before the setup I did the math to see if it was even possible to make the trip in time, given that I would now have to stop to sleep instead of being able to drive straight through the night if I had a chase partner to share the drive.  It looked like it would be possible to get there and get a few hours of sleep, and the 0z run of the models showed an improvement in moisture return and less cap for Saturday's setup.  This was enough to convince me to go.  I finished packing the mudpuppy and left Westchester at 10 pm Thursday.  I stopped short of Des Moines at 2:30 and camped in the back of the mudpuppy before getting up at 6 and continuing on. 

 

My initial target was Sterling, CO.  Initiation was forecast to occur first in southeast Wyoming during the afternoon, and then fill in to the south in northeast Colorado according to the 4km WRF.  The low level shear and instability was maximized over this corner of Colorado at 7 pm.  I arrived in Sterling at 3 pm, stopping to grab lunch and check data.  A beautiful green vista in eastern Colorado:
 

Storms were starting to fire in southeastern Wyoming, but I initially dismissed them.  They were moving northeast so I figured they were out of range, so the plan was to wait for new initiation further south.  Nothing was firing, however, and the 15z RUC also showed no further development to the south.  The decision to flee came suddenly.  I went north on a dusty, unpaved road that took me through some really neat looking sand  hills.  After crossing into Nebraska, I hit pavement and was able to make up some time.  The southern storm in the line was now tornado warned and had a hook on it although it was still 80 miles out.  I was determined to get it, however.  My county road took me to Dix, Nebraska where I turned west on 30 and then north again out of Kimball.

 

The visibility in the high plains is amazing.  I did a quick distance check on the radar and found that I was 30 miles out from the storm's base.  In Illinois there is no way you could see the base at this distance, but as I looked over my left shoulder there it was.  I could only get glances to the left between the hills as I drove, but I could see a well defined wall cloud and a couple of suspicious looking lowerings that could be tornadoes.  The tornado had been in progress for fifteen minutes at this point and is indeed the feature centered in this image, on the left side of the wall cloud.  The following few shots of the tornado are frame grabs from the robotic camera dome.
A couple minutes later, it was obvious that there was a stovepipe tornado on the ground.  The tornado was actually in Wyoming while I viewed it from Nebraska.
The stovepipe pushed out from the wall cloud as I raced north to find a west road option.  The backlighting and high plains visibility allowed me to plainly see the tornado from such a great distance.
I finally turned west on a dusty unpaved road south of Harrisburg, NE just as the tornado started to rope out.  It continued to push out from the side of the wall cloud, whereas most tornadoes are anchored under the wall cloud.  The shape was also a little unusual as it tapered in near the top.
I fumbled with aiming the camera while driving between the hills of western Nebraska.  My video was all over the place, but I was able to get a few decent frame grabs of the rope.
The tornado goes practically horizontal and ropes out into nothing just as I find a decent place to stop and view the storm.  I was able to get a few glimpses of a good portion of the tornado's lifespan, but it would have been nice to be parked for the whole show, and much closer.  View from about 15 miles east of the storm:
I parked the mudpuppy and let the storm come to me.  What started as a northeast moving storm had slowly turned right until it was now moving east-southeast.  The wall cloud still had some rotation left in it so I hoped it would cycle and produce again.
 
Nice structure:
The wall cloud fizzled and I started checking radar for potential new targets.  Some flanking line storms started to pop to the southwest of the supercell I was watching.  Looking west at one of them:
The base of the original supercell as it approached my position:
A lowering with weak rotation rapidly developed as the storm approached.  A few chasers from Minneapolis pulled up along side me and we chatted for awhile as the storm looked like it might produce again.
The lowering takes on a more classic funnel shape, but the rotation really was not strong enough for it to be called  a funnel.
Rising scud into the feature:
As the lowering developed I could make out what appeared to be laminar funnels within it.  They didn't last long, however, and the lowering soon evaporated.
Scudnado (a non rotating tornado look a like) develops on the northern flank of the base.
After sitting in the same place for almost a half hour, I finally moved east to keep up with the slow moving storm.  I followed a couple of mobile mesonets down a steep and winding road to drop south and then east.  Looking north at the storm's base with the precipitation core on the right, the rain free base on the left, and a lowering the middle:
Looking back at the entire storm:

This is one of the best photographs I have taken while storm chasing.  The lightning capture was a total fluke.  I didn't even realize I had captured the lightning until I reviewed the pictures the next day.

Bubbling convection on the top of the updraft tower.
The storm a few minutes later.  Note the horseshoe base underneath:
A large lowering started to develop under the base of the storm as it passed over Dalton, NE.  It looked like a massive wall cloud and was very dramatic in appearance, but as I approached the storm I realized it was a massive wall of scud.  The storm was gusting out and going outflow dominant, meaning it was dieing.  I followed it a bit longer until I was sure it was done (at least from a chaser standpoint) before bailing back west to get to a southbound highway. 
 

Heading west, however, I ran into a chunk of the Vortex2 research team.  Their mobile doppler radar truck stopped abruptly in the middle of the road and started scanning the area behind us.  Apparently they detected a large embedded tornado in the core of the storm.  I knew I wouldn't be able to see an embedded tornado, and had my fill for the day so I continued west and then south, calling it a night.

 

Heading south towards Sidney, NE I got out under the anvil of the storm and saw my first good mammatus of the year.  A gorgeous display that I'm glad I didn't miss by chasing an outflow dominant storm into the darkness.

After bagging a nice tornado and a gorgeous supercell, a celebration was in order.  I called all the chasers that I knew that were in the area and organized a chaser tradition: steak dinner.  On the edge of Sidney I found Dude's Steakhouse.  After running around all day eating junk food or no food, getting out of the van and smelling that steak was heavenly.  Storm chaser and meteorologist Stan Rose pulled in next to me at the lot.  After introducing ourselves we got a table and waited for the rest of the crew to join us.  The Minneapolis guys I met earlier were already in there and I took a picture for them eating their celebratory dinner.  We were soon joined by Adam Lucio, Danny Neal, Jesse Risley, Mike Brady, Brandon Sullivan, Scott Bennett and Ben Holcomb.  We all had a good time sharing stories from the day.  It was the perfect end to a great chase.

 
Conclusion:

This was the chase of the year of the so far.  Even though it was the furthest distance I have been from a tornado during a tornado intercept (at over 30 miles when I first made it out), I could still plainly see it.  I wish I could have been closer and gotten better video of the event, but it was still a nice catch.  The awesome supercell structure that followed really rounded off the chase as well.  It was a great success in my opinion and justified the entire trip.  No matter what happened weather wise the next two days I knew I would go home happy.  Lots of chasers were positioned a lot closer to the tornado when it happened and got stunning video.  The most amazing was from the Vortex2 research team.  As the tornado roped out and went horizontal, they were positioned to look up inside the funnel and could actually see a smaller condensation funnel spinning from within.  It was amazing footage, and I'm glad they finally got good data from a tornado after weeks of roaming the plains empty handed.  The tornado was rated EF1 and was one of only a couple that formed that day.

 

Lessons Learned:

  • Move on initiation.  You can always drop back to your original target.
  • The visibility on the high plains allows visual intercepts from incredible distances.