Green Sky Chaser

18 May 2010 Chase Log



Target Area: Dalhart/Amarillo, Texas (Click on city names for Yahoo! maps links)

Chase Area: Hartley/Stinnett, Texas

Observations: two tornadoes, two or three funnel clouds, five or six wall clouds, one supercell, lightning, green sky, and a coyote

Distance: 730 miles

Time: 17 hours

Chase Team: Jeff Makowski and myself

SPC Convective Outlook: Slight Risk (upgraded to Moderate) (Click to see SPC products, data, and storm reports)

Chase Setup: A trough approached the Four Corners region and an elongated surface low formed in southeastern Colorado / eastern New Mexico. A dryline extended southward through far eastern New Mexico while a warm front stretched from the low in southeastern Colorado through the far northeastern Texas Panhandle into northern Texas. Dewpoints ahead of the dryline into the Texas Panhandle were in the upper 50s to lower 60s and CAPE was between 1500 and 2500 J kg-1. Mid-level lapse rates were over 8 oC km-1 in the north Texas Panhandle while the cap was weak to non-existent. Storm-relative helicity values were over 300 m2 s-2 in the west Texas Panhandle.

Blog Entries:

Chase #8 (during)

Chase #9 (after)

May 18 and 19 Storm Chases (#8 and #9) (after)

Update on May 18 Chase - Two Tornadoes (after)

Chase Log: Jeff and I left Norman just after 9:30 am, to head west out on I-40. Neither of us had been as far west on I-40 as Amarillo, so we were both excited just to go out and enjoy the Texas Panhandle. When we got to Amarillo, we briefly met up with Dean Narramore (from Australia) and Willoughby Owen (from New Zealand), both out on a six-week "chase-cation". After stopping to take photos of The Big Texan (famous steakhouse), Jeff and I drove north up Highway 287 to Dumas.

After sitting at Dumas for a while, deliberating on whether to go farther north up to Dalhart or to go west towards New Mexico, we eventually just drove west on Highway 87 to Hartley. Shortly after arriving at Hartley, we noticed the first blip on the radar had popped up just to our southwest.

We drove off to meet the little storm, and saw the beginning stages of what would soon become a large, HP, tornadic supercell. At first the cloud's non-rotating updraft base appeared so high up, I was concerned whether or not we would eventually get a nice supercell. I was later astonished at how quickly the base lowered.

As the storm started to drift away from us, we followed it back north and east and watched with amazement as the updraft base began to strongly rotate and two wall clouds formed, with their bases so low they appeared to be scraping the ground. A brilliant, turquoise hail shaft grew in size and eventually appeared to be coming straight out of the enormous mesocyclone. We saw several wall clouds form as we paralleled the storm, but mostly missed the rain-wrapped tornadoes that were reported as chasers viewed the supercell from a different vantage point.

In reviewing later footage, I did find that one of the lowerings we saw was a cone tornado just east of Dumas at 6:43 pm, which matches up with the time and location of a 200-yard-wide tornado report.

We followed the storm to Stinnett, where we stopped briefly at a gas station. As soon as we got back into the car, the tornado sirens started to go off. The mesocyclone was rapidly approaching Stinnett, along with a reported tornado. We drove about a mile south of town and then stopped and looked back. It was difficult to see much in all of the rain and hail, but we did see an elephant trunk funnel cloud get about halfway down to the ground, passing just north of the gas station. A few minutes later, a small cone tornado came out of the rain and roped out (we did not see the debris cloud when there, but reviewed photos and video as well as time and location to confirm that it was the tornado). We later found out that this tornado was rated EF2, and was on the ground for about 15 minutes.

We continued to chase the storm for the next hour, but it started to get dark so we stopped for a while to watch the amazing lightning show (mostly intracloud, though we saw a few cloud-to-ground strikes). The structure on this supercell was some of the most incredible and breath-taking structure I had ever seen.

We got back to Norman at just after 2:30 am, after a great chase through some beautiful country.