May 20, 2011 Chase Update

Hi all, it is happy update time!

My first tour (Tour 2) concluded a week ago (around May 13).  After our two good supercell days in SD and NE (May 8 and 9), we  repositioned on May 10 to Dodge City for what we thought would be a big day on Wed, May 11.  But, Wednesday busted badly.  A lot of morning convection trashed the atmosphere and we were left with a junky and brief cell near Dodge City around 6 p.m.  Part of our group had flights the next morning, so we got back to OKC at midnight.

A couple of guests continued with us on Thu and Fri, May 12 and 13.  On the 12th we were on some convection in north Texas near Nocona, and then dropped a little southwest to a pretty tail-end supercell near Springtown.  Structure with this small cell was impressive for a little while, including a blocky wall cloud, but it slowly shriveled to nothing as it approached our location.  We headed back to OKC on Friday and I had the weekend off to relax.  The next tour began on Monday.  Luckily for me, the weather pattern was very poor for chasers, and cool north winds blew through OK.

The atmosphere continued to be quite dry on the Plains as Tour 3 commenced, though winds were starting to come back around from the south.  After guest orientation on Monday (including Jim Cantore and two cameramen working for The Weather Channel), we visited the BRIDGE OF DOOM near Hollis and stayed the night in Childress.  There were indications that West TX might get some severe weather on Tuesday, May 17, but that idea fizzled out and we bolted north.  We had a good look at the terrible drought conditions in the OK and TX Panhandles on Tuesday, as strong southeast winds kicked up areas of blowing dust.  Forecast charts suggested some stroms along the KS/CO border, and we hung out along the south end near Hugoton, but nothing went up.  Some stronger activity occurred several counties north near I-70, and I was miffed that I had not continued north for that.

On Wednesday, May 18, we began in Liberal, KS.  We visited Dorothy’s House, and then decided to start west into southeast CO.  I figured that our chances for a good storm were much better here than in the other possible chase target — NW OK.  Well, after 30 or 40 minutes and rechecking data, I turned the group around and headed towards NW OK.  Prospects for a great supercell storm or two in western OK were increasing, and the tornado potential if a storm went up appeared quite good.  We made it southeast of Woodward in time to see a storm cell develop, and it had a laminar rotating base, but it was small and it didn’t last long.  Thick high clouds started covering western OK (practically out of nowhere) soon after a tornado watch was issued, and these clouds wrecked the day for chasers.  There were no storms at all in the watch box!  Meanwhile, a nice supercell was moving along east of Pueblo in my original target area of SE CO.  That’s how it goes sometimes.  On this day, when I turned around west of Liberal, I decided that it would be better to give ourselves the chance to see a significant and long-lived tornado—-and that chance was in western OK.

Low-level moisture was finally at acceptable levels on the southern Plains on Thursday, May 19.  And, the big trough in the West was over the Rockies.  The setup for big tornadic supercells appeared to be pretty good near a warm front in central KS.  We were in Pratt and ready for action!  Here is a forecast that I made mid-morning:

We will play the warm front just northeast of the triple point surface low. The Pawnee County area just west of Great Bend might be a good place to hang out (we are near Pratt currently). There does appear to be a fairly wide-ranging area today to choose from and, at the moment, I can’t find an arrow that says “go here”. So, we’ll stick to Storm Chasing 101 basics and find some sunshine on the backed winds near the surface low. The models appear to break out storms rather early, which I dread. Good luck to everyone.

We spent a couple of hours around noon going back and forth through Pratt, and then bolted north to get close to the warm front.  Here is the summary that I wrote:

The chase went pretty much according to plan today, for once. We (Chris Gullikson, Chad Cowan and I) began in Pratt and targeted the area just northeast of the triple point/dry line bulge which was west of Pratt midday. There was plenty of sunshine and it looked like the atmosphere was going to go into storm-making mode by noon, but it held off, fortunately. One concern today was that a storm would form in the good air along the NW-SE oriented CAPE axis and then quickly move NE into the cool murk north of warm front. At 2 p.m. the wind at DDC shifted to SW. Wind at Great Bend was SE and moist, so that was the impetus to get us moving north from Pratt. We continued just past Great Bend, and a healthy CB developed right in front of us. We stayed with it towards Russell and it matured into a supercell, though somewhat of a messy HP supercell. We were behind it a little on its west side as we reached Russell, and then jumped on I-70 eastbound. After a couple of brief stops to allow a hail core to pass, we made it through to the north and then the northeast side of an elongated updraft base with a couple of action areas. Near Dorrance, an area tightened up some and we saw dust get kicked up beneath it. It was dark and nasty looking and the base was quite low to our west —- we were a little north of the warm front, and east winds were strong. Someone reported a tornado with the storm a little north of I-70  —- our group did not see one for certain (though Chris’ video shows a power flash). The cell seemed to move more to the NE and more slowly now, and we managed to get in front of it at Sylvan Grove. Inflow winds from the NE gusted to near 50 mph, and rain curtains swirled around beneath the large base to our SW. It chased us a little east of Sylvan Grove as the sirens wailed, and we stopped after going about a mile east on 18. Here, the winds were dead calm, and an area of strong low level rotation was developing just south of the road. I thought we were going to get a tornado at close range at this point, but it couldn’t pull it off (though, again, a tornado was reported with the storm by a spotter).

We went north of Lincoln a little for one last look. The cell seemed messier and less organized, and the air was murkier, and it seemed that tornado prospects were slim. So, we blew it off in order to get south to a tail-end cell near Great Bend, but this cell weakened. A couple of cells went up on the retreating dry line near Dodge City, so we went SW and stopped at Rozel for a very pretty sculpted (though elongated) storm at sunset. As the light faded it looked like the storm base was issuing some funnels to our N, and then a tornado warning was issued. We blasted north on 183 to get a closer look, but the cell quickly disorganized.

This was a fairly satisfying chase as the forecast worked out and we managed to stay with a fast-moving supercell from formation to maturity.

Images for this storm and the previous chases will be posted as time allows!  One of our guests for Tour 3 is posting a blog here, and another guest has one here.