May 19, 2003: Loco and Healdton, Oklahoma supercell and wall Cloud

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

May 19 was a surprise chase day with unexpected results. I started at the Super 8 in Hays, Kansas at about 9:30AM. There was a very cold northeasterly wind, intermittent rain and a temperature of about 60. After saying goodbye to Chris Kridler, who was heading home because of a family emergency, I drove east on I-70 and then south on I-135 toward Oklahoma City. A very strong cold front was moving through the region and was expected to trigger storms in Oklahoma. Because of a lack of strongly turning upper-level winds and a very capped (suppressed) atmosphere, neither supercells nor tornadoes were expected. These storms would form a line with gusty winds and small hail. I agreed with the Storm Prediction Center that severe storms were possible but not supercells. I didn't plan to chase and was mainly driving back to Norman to rest and meet with Becky Lee, a producer from Pioneer Productions in London. Becky and her crew were working a storm chaser show that will be aired on the Travel Channel. She wanted to interview me and possibly go on a storm chase. While driving south, I did try to obtain weather data in Perry, Oklahoma. My modem couldn't read the signal from a telephone line at a local diner and my new wireless cell phone modem was still not operational. (it worked well in Virginia.) I wasn't concerned since the forecasted storms would not be worth chasing. I crossed the frontal boundary near Guthrie, Oklahoma. The temperature rose from the low 60's to mid 80's and the winds switched from northeast to southeast. The sun appeared among scattered clouds. I arrived in Norman, Oklahoma and checked weather data at my hotel room. A severe storm watch was issued for areas south and west; however, only a line of storms was predicted. The radar already showed the line forming to the west. After seriously considering a nap and blowing off the storms, I decided to take a short trip to the southwest. One storm did have a severe warning and maybe I could encounter some small hail. I called Becky, who at just left a few minutes earlier with some other chasers, and we scheduled the interview for the next day. I headed west on 9 and south on 76 at 5:35PM. Choosing a storm would be difficult as there were several in a line. Visibility was poor due to fires in Mexico. Distant storms appeared as dark areas among the background clouds. In clear air, a chaser can look at several storms and decide which is the better target. At 6:30PM, I talked via cell phone with Tim Vasquez who gave me a radar interpretation. One storm much farther to the south had a mesocyclone and was isolated from other storms. It was a supercell. Unlike the other storms that were moving to the northeast, this was moving to the southeast or "right-turning". Storms that right-turn are able to add more spin to their local environment. I was still far away and had to plot an intercept. I had to account for the storm's motion vector, my approach and how to avoid the hail-containing core while arriving at storm in time for a possible tornado or at least a great structure photo. The storm could die at anytime. I couldn't drive due south because I would have cross a region of large hail, blinding rain and possibly a rain-wrapped tornado. I headed west on 19, and I turned south on I-35 at 6:30PM. I was slightly delayed in construction as I crossed the Arbuckle Mountains. It was very frustrating as I imagined the storm merging into a line and losing strength. They sky was now dark to my west. I turned onto 53. A tornado warning was issued at 6:50PM. I turned south again on 76 at 7:08PM. The storm was to my west and the base initially appeared too high. By 7:11PM, I saw a large dark rotating wall cloud (1V) attached to the storm. It could drop a tornado at anytime. The meso was 10 miles east of Loco per another radar update from Vasquez. I parked near the 53 and 76 intersection and watched the wall cloud. There was possibly a brief funnel. Several storm spotters from a nearby town also watched the storm. Eventually, rain wrapped around the wall cloud decreasing visibility. At 7:15, I moved south to avoid the rain. Soon, the wall cloud (2V) was visible over the trees toward the west. I parked at the edge of Healdton. The wall cloud (3V) was backlit by the setting sun. A group of locals came by, pointed at the wall cloud (4P), and exclaimed, "Welcome to Oklahoma!" One later told me that he earlier saw a brief funnel. The wall cloud began to widen (5V)(pic 1),(6V)(pic 2), (7P)(pic 3) by 7:23. Rain and hail were approaching the town. I continued through Healdton passing by groups of residents (8V) watching the approaching storm. I did see another area of rotation (9V) at 7:41; however, the storm began to lose its organization and "gust out." I watched the swirling clouds with additional brief episodes of rotation (10V). Further east, I stopped at a large chaser convergence (11V) and ran into George Kourounis and several other chasers along with the crew from Pioneer Productions (12V). I had previously met George through Chris Kridler last year. He was chasing with a couple of chasers from Canada and upstate New York and another group from New York City. After deciding the storm had completely died, we all went back to Norman for a late evening dinner at Denny's. All of us were staying at the Guest Inn, a local chaser favorite, in Norman.

(1V) (2V) (3V) (4P)
(5V) (6V) (7P) (8V)
(9V) (10V) (11V) (12V)

Although no tornado was sighted, this was a successful storm chase. A great storm with beautiful structure was intercepted and photographed. If the upper-level winds had stronger, I am sure the storm would have produced a tornado.

(P -- Photo) (V -- Video Still)

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