Hill City, Kansas Tornado: May 22, 2007

 

 

chase images and log by William T. Hark, M.D.


YouTube video of supercell formation and tornado. (9 min 47 sec)


Conditions were very favorable for severe storms. There was a trough over the Rocky Mountains, a deep upper low over northern Wyoming, and surface low in North Dakota. Another low was in western Kansas with a trailing cold front. Surface dewpoints in Kansas were predicted to be in the low to mid 60's. As better upper level winds were to move into the northwest Kansas area, supercells were possible especially near the triple point by evening. I blew off the possibility of storms farther south along the dryline due to weaker upper level winds and increased cap. I was initially targeting the Wakeeney, Kansas area.

I started the day in Woodward, Oklahoma and eventually stopped in Wakeeney, Kansas to eat lunch at a Pizza Hut and check data. I was a bit concerned that the 17 Z RUC was showing better backing of surface winds toward the Kansas/Nebraska border but the initial precipitation on the WRF at 2100 Z was just east of Oakley. I decided to shift northwest to Hoxie and wait at a convenience store with good Wi-Fi. Hoxie is in a crossroads, and I could easily drive out in multiple directions While driving north on 23, I noticed some thickening of the high-based cumulus covering the area by 3:00PM. I soon arrived in Hoxie and checked more data. I liked the initial vertical development of the cumulus by 3:30PM. (Image 1V at 3:50PM CDT) While waiting, I encountered many other chasers including Roger Hill of Silver Lining Tours. There were several areas of development in a north-south line from Grove County to near the Nebraska border. The main area was near Grove and moving northeast. I briefly waited to make sure that the southernmost storm would be dominant. My route south from Hoxie was blocked by the growing storm. I decided to head east on 24, then south from Moreland on a marginal road to intercept the storm. I again passed Silver Lining Tours. By 4:55 PM, I was south of Moreland on a dirt road watching a nice developing storm to my south-southwest. Unfortunately, my route south was getting blocked and the storm was turning right instead approaching me directly in a northeast path. It was also starting to split. My east-west options appeared marginal, and I didn't want to core-punch the storm. I blasted north, then east on 24. At 5:20 PM, the southern split was briefly showing shear markers on radar. I had to hurry as I expected the main storm to be initially tornadic before merging into a line. By 5:26PM, I turned south on 283 at Hill City. The storm was visible to my south and west. A funnel cloud was reported in the St. Peter's area at 5:29PM. At this point, I thought I had lost the chase as I had waited too long and was too far away. I turned west on a dirt road (406) at 5:35 PM. The storm was high based, but I could see a wall cloud to the southwest by 5:40 PM (2V). Another meso was forming farther to the southwest but not as well developed. (Image of both mesos 3P at 5:43 PM) A brief funnel (4V) formed at 5:43PM then there was some lowering of the base and another brief funnel at 5:45 PM. I saw no evidence of ground circulation. The wall cloud continued to rotate with beautiful structure (5P 5:48PM), and almost another funnel (6P) but it would be cut off by the larger storm to the south. I headed south by 6:08 PM to intercept the next storm. I turned west and drove toward the massive meso by 6:14 PM. I could see the vault. The whole storm was rotating. I pulled over at 6:15 PM to take photos of the huge storm (Image #1 7P), Image #2 8V)) to my west. As the storm neared, I drove back east then north. I again parked at 6:40 PM. The storm (approx 6:59 9P) was to my northwest. Inflow was increasing, but the storm was initially appearing rather "HPish". There was a well-defined funnel (10V) by 7:04 PM. I drove north for a better view. Rotation was rapid, though the funnel lost some structure. I continued north on the dirt road. Touchdown (Image #1 11P), (Image #2 12P), (Image #3 enhanced 13P) was at 7:09 PM. After a couple of minutes, there was less ground debris (?tornado lifted) and I moved north again to get closer to the storm while dodging areas of mud. The funnel (Image #1 14P), (Image #2 15V) was whiter but the debris cloud was difficult to see. I turned east at 7:13PM. I didn't like the appearance of the muddy road farther to the north and was afraid of getting stuck. "Rope-out" (15P) was rapid at 7:15 PM.

I drove east, then north on 283. The meso crossed the road to the north but no additional tornado. I had to briefly wait among a hoard of chasers while stuck between two cores. I tried to intercept another tornado-warned storm in the Palco to Zurich area but darkness arrived. I drove to Hays to upload some video, but another massive storm was approaching the town. The tornado sirens started at 9:30PM. I quickly got some gas and shifted east to watch the storm before ending the chase. This was a rare day with both a nice tornado and great storm structure.


(1V)

(2V)

(3P)

(4V)

(5P)

(6P)

(7P)

(8V)

(9P)

(10V)

(11P)

(12P)

(13P enhanced)

(14P)

(15V)

(16P)

 

Mobile Threat Net Radar Images and GPS log (My position is the white spot on radar images)

4:55 PM CDT 5:20 PM CDT 6:05 PM CDT
6:37 PM CDT 6:42 PM CDT GPS Log

May 22 Weather data and forecasts including surface, upper air, satellite, and model output

Day 1 Outlook Tornado Prob 250 mb 500 mb
850 mb 1815Z Sat 2015Z Sat 1833Z Surface
2023Z Surface 12Z NAM Surface 00Z 5/23 12Z NAM Precip 00Z 5/23 WRF Precip 2100Z
WRF Precip 2300Z 12Z RUC 500mb 00Z 5/23 12Z RUC CAPE 00Z 5/23 12Z RUC Dew 00Z 5/23
12Z RUC Precip 00Z 5/23 12Z RUC Surface 00Z 5/23 . .

 

Next Page: May 23, 2007

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