June 19, 2011

Statistics:

Initial Target: Sterling, CO
Departure: Westchester, IL 10:00 pm June 18
Arrival: Kearney, NE 12:00 am June 20
Intercepts: McCook, NE
Tornadoes: 1
Hail: None
Wind: Non-Severe (not measured)
Features: Tornado, Wall Cloud
Miles: 1267

Summary:

High plains/dryline setup across eastern CO/western NE.  Targeted northeast Colorado for afternoon initiation of upslope supercells.  Followed storm west of Julesburg, CO back into NE panhandle.  Storm exhibited dramatic high contrast, structure, and wall cloud, but was cold and outflowy.  Abandoned storm just as it gained tornado warning, heading for new development in southwest NE.  Intercepted training line of tornado warned supercells north McCook, NE, chasing first HP cell before letting the next cell in the line come to us.  Noted briefly condensed, backlit tornado that persisted as a debris cloud before dissipating to our south.  Followed cell until after dark before calling it a chase meeting up with chasers at the Perkins in Kearney, NE.

Crew and Equipment:

Chase partners: Jennifer Brindley, Adam Lucio, Jonathan Williamson.  Equipment:  Kenwood TH-F6A Tribander, Dell Inspiron Laptop.  Millenicom 760 USB datacard and cradlepoint router, Holux 236 GPS, Canon 60D and EF-S 10-22mm

Photography courtesy: Jennifer Brindley

Video courtesy Jonathan Williamson

Video:

Details:

Usually the peak of severe weather season, the first half of June was dead.  Finally, it looked like we'd get a couple of chase days in on June 19 and 20.  A day before the day type upslope/warm front play was setting up for Sunday and the bigger day, Moday, looked like a potential outbreak with a strong trough ejecting across the plains.  I worked Saturday in exchange for Monday and made plans to team up with Jennifer Brindley, Jonathan Williamson, and Adam Lucio.  With the Mudpuppy now retired after 250,000 miles, this was the maiden chase for the new minivan, a '10 Chrysler Town and Country.  I hadn't equipped it at all yet for chasing, but was anxious to see how it would do on a chase.

There were a few targets to consider on this setup.  Initiation looked like it would occur first over the high plains of northeast Colorado where surface winds were out of the east creating lift as they flowed over the rise in terrain.  Dewpoints and temperatures were quite modest over this target, but adequate for the higher elevations.  This target was also closer to the trough which was still forecast to be out over the Rockies, so the wind shear looked a little better.  To the east across southern Nebraska, there was an east west orientated boundary that was lifting north like a warm front but had a lot of dry, hot air behind it like a dryline.  Instability was forecast to be much greater along this boundary, and helicity was higher as the winds strongly backed north of the boundary.  Capping looked stronger in this region, so initiation looked to come later when the midlevel temps would cool and enhanced lift from the trough would arrive.  Even further to the east in northeast Kansas, an EHI bulls eye existed where the highest instability and helicity along the boundary came together.  Capping was even stronger here and speed shear lighter so initiation looked questionable.  If a storm did go up, however, it would probably be the perfect chase: an isolated, slow moving supercell.

We decided to make for the upslope play.  Adam, Jenn, and Jon converged on my place the night before the setup.  We loaded up the van and were off for an overnight drive taking 88 to 80.  We took turns behind the wheel, making it to North Platte, NE by 11am where we stopped for a brief breakfast.  I wound up getting popcorn and an iced coffee from Starbucks: not a good combination after you've been up all night. 

We made it just across the border into Colorado by 1 stopping for lunch at a Subway in the dusty little town of Julesburg.  We weren't there terribly long before storms initiated about 50 miles to our west.  We debated whether or not to go after them at first as they were moving north-northeast, which would make them difficult to catch and put them out over drier air eventually. 

We went for it, however, and wound up heading straight back into Nebraska and shooting west on 80, having only made it into Colorado a few miles and staying less than an hour.  A couple of cells were tracking into the Nebraska panhandle.  The forward most looked promising and turned right toward us, making our intercept easier.  We got off the beaten path at Sidney, NE and headed west on some unpaved roads through the sand hills.  The anvil, wispy and ragged, stretched overhead.  The amazingly clear air of the high plains let us get peaks of the base from more than twenty miles out as we crested the tops of hills.

Jonathan driving us to our first storm of the day:

 

We stopped a couple miles from the base of our storm, which held a severe thunderstorm warning.  The contrast on the storm was amazing, but there wasn't too much happening under the base.  The inflow into the storm felt cold.  Temperatures were probably in the low 60's to upper 50's and dewpoints in the low 50's.  It was almost uncomfortable being outside in short sleeves, but huddling by the heat coming off the van's engine and the excitement from being out on the chase kept me warm. 

We let the storm come to us and a wall cloud started to develop with a classic tail cloud.  There didn't appear to be much in the way of rotation, however.  We stayed for a good 45 minutes, letting the slow moving storm approach our position with amazing color and contrast.  The northern end of the wall cloud was getting away from us and starting to look interesting so we moved north up a gravel road to get closer. 

We went north to to keep up with the storms, but they soon lined out with just a lot of fast moving scud.  I thought our chase might be over so we stopped for gas in Parkston and checked radar. 

 
 
Jonathan and Jennifer sporting hoodies on a June chase:
Adam shoots a tail cloud developing under the ragged base:

Along the way we bumped into JR Henley and Ben Holcomb.  We stopped to say hi and watched the base of the storm move overhead before running east to stay ahead of it. 

 

 

We zig-zagged until we got back up to 80.  The base of the storm had fanned out in a huge gust front.  It looked cold and outflowy.  The structure was photogenic but I was fairly sure the storm wasn't going to produce any tornadoes.  We reassessed our situation.  An agitated area of cumulus was forming to our southeast in the southwest corner of Nebraska.  This area was strongly destabilized and had nice shear profiles for supercells. 

 

After a little debate, we decided to abandon our storm and race east and south in the hopes of catching more promising storms later that had yet to develop.  Minutes after leaving, however, the National Weather Service issued a tornado warning on our storm.  We took the next exit and watched the base from a few miles out, but saw the same structure we had decided to abandon: a cold, outflowy base with a strongly forced, laminar gust front.  We continued east on 80, while the tornado warning lured most chasers into staying on the storm longer.

 

The Storm Prediction Center issued a tornado watch for southwest Nebraska for developing suprecells.  As we approached North Platte, several storms were popping up up across the watch area.  The ones closest to us were faltering, however, with a few by the Kansas border becoming dominant.  After a quick stop for gas, we headed south out of North Platte for the intercept.  The storms quickly blew up into tornado warned supercells, with three large cells riding on each other's heels in an east to west line.  The middle cell looked the most promising and had reported tornadoes so we left highway 83 at Maywood, making for Hayes Center. 

The plan was to cut south between the forward most and middle cells, avoiding the cores of each.  Our road twisted and turned through the southern Nebraska sand hills, however, slowing us down so that the storm had crossed our route before we could make it to Hayes Center.  Vertically integrated liquid, a radar plot used to gauge potential hail size, was off the charts.   Instead of gambling with a risky core punch with potentially huge hail through winding roads, we decided to cut south ahead of the first cell and make a play on it instead.  Our roads went to loose gravel as we got off the beaten path and I was worried we might get into trouble as the rain from our approaching storm further degraded the roads.

We beat the core of the storm after turning around a couple times and taking a gravel road south a couples miles west of 83.  Our storm was a dramatic looking high precipitiation supercell, but there were no tornadoes visible under the base.  We stopped for picture before continuing southeast to get out of the way of the storm, and let the next in the line come to us.  The forward most cell slid off to the north with a lot of scary looking scud being kicked up in its wake.  The next storm appeared on the western horizon with a broad base, backlit by the low sun angle.

 
 
 

Mneawhile a local woman slowly pulled up in a truck, with a skiddish dog following behind at a quick trot.  She stopped to see what we were up to and what the storm was doing, the dog holding its distance a dozen yards down the road.  Eventually she asked for our help getting her dog.  She said the storm had spooked him and he wasn’t willing to get in her truck as a result.  Williamson was able to approach the dog, but couldn’t get him back to his owner, while Brindley got one of her “local’s portraits.”  The woman evnentually continued on down the road, with the dog trotting behind as the storm approached from the west, still a few miles out.

 
 
 
 

The storm approached with dramatic contrast and color.  The rear flanking core had fanned out into a big gust front, but there was a lot of motion behind, signaling signs of redevelopment.  The rear flank emerged as a very low, rotating wall cloud as the gust front started to move over head. 

 
“Tornado!” somebody called out.  I was watching a dangling, weakly rotating feature overhead so I thought that was what everyone else was watching.  I didn’t spot the small, intermittent, trunk shaped tornado on the rear flank until a few moments later. 
The funnel skipped a bit, retreating into the base before briefly reforming. 
 
 
 
The debris cloud defining the tornado persisted, however, even after the funnel permanently disappeared into the base.  We watched it for several minutes as it started to pass to our south.  The circulation eventually merged with some outflow and was carried away in the straight line winds.  We held our ground, waiting for the area the circulation was under to pass to our south, not wanting to cut south in front of it if it redeveloped.
 
 
 
 

The rear flanking core hit us with some wind and rain and we were back on the move trying to keep up with the storm, from behind the area where it produced.  We crossed 83 and stayed with some gravel roads to avoid driving through McCook.  We zig zagged down the gravel as fast as the rain and road conditions would allow.  We made it down to highway 6 and were able to blast east ahead of the storm.  We also encountered the chaser hordes, one of the few convergences I had seen all year including the Twistex team and more than a dozen other vehicles.  The traffic didn’t hinder us though.  We dropped south again as highway 6 veered northeast slightly and the storm had turned right, which would have put us back in the core.

The storm transitioned to a permanent high precipitation mode, however, and we never got our good view of the base back.  Night started to settle in so we transitioned into more of a lightning chase.  The lightning wound up being mostly cloud to cloud and too infrequent to get good stills so we started heading north to break off the chase.  Along the way we wound up near Rob Hurkes, Nick Nolte, LB Laforce and his dad.  Brindley spotted a lowering under the base off to our east so we got on a clay road to go after it, but we couldn’t find it again and I was worried the road would get dicey so we decided to call off the chase and get some dinner. 

We all caravanned up to Kearney, NE (where the infamous wheel flying incident occurred a month ago) and got some dinner at the Perkins.  It was midnight by the time we showed up, however, and our group overwhelmed the staff so it took over an hour for everyong to get their food.  We had a great chase, but everyone was too exhausted to really celebrate.  Adam, Jon, Jenn, and I split a hotel room a few blocks down the road.  A derecho cored us not long after we arrived, which Adam, and Jon stayed up for.  I was just tired after our overnight haul and all day chase to western Nebraska, however, so I crashed.

 
Conclusion:

The maiden voyage of the new van was a successful chase.  We got great high plains structure as well as a brief tornado.  The tornado we spotted did little if any damage and was rated EF0 after staying out over open country.  A more photogenic tornado occurred near Max, NE.  Had we cut south a little sooner and gotten on the middle cell in the training line like we originally wanted, we might have had a shot on it.  Still an awesome chase, and it was great meeting up with a bunch of friends afterwards.

 

Lessons Learned: 

  • High plains supercells that don't produce can still be extremely photogenic.

  • Don't show up with a dozen chasers at the Perkin's in Kearney, NE after midnight.