Storm Chase 2001: May 20

Tornadic storms, funnel, wall cloud, anvil crawlers (archived weather data at bottom)

I left early in the morning from Norman, Oklahoma under overcast skies and headed to Ardmore where I planned to check more data before making a final target in SE Oklahoma. There was deep moisture across the area after the passage of a Mesoscale Convective System (MCS) and old outflow boundaries from the MCS would serve as a focusing mechanism for storm development. Dry air would be moving in from the west. There was sufficient shear for tornadic supercells. The area was under a Moderate Risk from the Storm Prediction Center (SPC). I had planned to target an area between Durant and Hugo, Oklahoma but I decided on a more northerly area close to Ada. As I was leaving, I ran into Jason Persoff, M.D., Scott Blair, Jason Politte and then Wayne Curtis who is doing an article for Atlantic Monthly and Oliver Staiger from Switzerland. Pioneer Productions was following Jason around for special on storm chasers. By 12:00 PM, the clouds were starting to break apart with blue sky visible. Sunshine would increase heating and the instability of the atmosphere. There was also some vertical development. I joined up with those guys and we headed north in a big caravan to Davis to wait for storms to develop. We waited (1P)(L to R: Jason Persoff, Bill Hark, Scott Blair, Oliver Staiger) at a truck stop (2V). By 1:00, turkey towers were forming. Shear was visible by 2PM. We then moved north to Pauls Valley and we waited and watched. According to The Chase Hotline, satellite imagery indicated that organized towers were developing along an axis from northeast of Ada OK to south of Purcell OK to Rush Springs, and a secondary cluster of Cu was developing south of McAlester into the Tuskahoma OK area. There was development all around us by 3:00PM. We could see shear to our north (3V). The SPC issued a Particularly Dangerous Situation (PDS) tornado watch. We were watching areas to our east (pic of Jason and Scott) (4V) and northeast to decide which area to head. We could see a storm developing to our north-east but we weren't yet sure if that was the storm to target.

At 3:30, we decided to target the north-east storm. We drove east on Route 19, then north on Route 177. We could see a storm (5V) with an overshooting top, knuckles and we observed the development of a flanking line. We turned east on Route 59 and our caravan got separated. Then it was just Scott Blair and myself. We learned about a tornado warning for the storm at 4:25PM. We could see a huge hail shaft. After Maude and Seminole we picked the northernmost of two close-together tornadic storms. We blasted east from Wewoka on a dirt road (6V) at 5:00PM. Scott was doing an awesome job navigating. The road was a bit scary with deep muddy ruts and dogs chasing us. I lost Scott somewhere near Wetunka. I headed east on Route 9 in blinding rain and wind trying desperately to get ahead of the storm. At 5:46PM, I passed the damage path on Route 9 just east of Dustin. Indian Nation Highway was closed near Dustin due to damage.. The TV station out of Tulsa (audio on FM ?87.7) did a great job with their storm reports. At 6:22PM, I was in Eufaula during the tornado warning. There were reports of visible rotation. All I saw was rain and wind. I was hoping that the curving of Route 9 to the south and across the lake would bring me out of the rain and allow me to view the storm. I passed the DOW at 6:30PM by the lake. I was still in heavy wind and rain. No storm structure or even hail. At 6:45PM while in Enterprise, Oklahoma, I decided I couldn't catch up with the storm and turned south on Route 71 then east on 31.

I knew there was another tornadic storm approaching from the south-west. I then drove south on 82 from Lequire. Wow, there are mountains in Oklahoma. I felt like I was in western Virginia. The mountains were obscuring most of the storm. I watched the storm until about 8PM. When it was close, I dropped south to Red Oak for a safer observation point. At 8:11PM, I observed a ragged wall cloud (7V) and a very brief funnel. The funnel (8V) lasted a few seconds and broke up along with the wall cloud. As it was getting dark, I decided to end the chase and head to McAlester. I had a scare in Wilberton. While entering the town, I was hit with blinding rain and blasts of high wind. There was a tornado warning for the town. There was a bright flash to the southwest and most of the power went out. At the same time, a gust of wind caused a power line to brake off sending sparks showering to a parking lot. I guess it was on a different circuit since the lights were already off. I was scared and briefly looked for shelter before deciding to continue. When out of the rain, I could see another storm to the southwest with an awesome updraft and anvil. At the Super 8 in McAlester, the whole parking lot was filled with chasers. I ran into Chris Kridler and Dave Lewison among many other chasers. One even had a PT Cruiser as a chasemobile. Several of us watched a nice display of lightning (9V) as another line of storms passed by.

A very frustrating and dangerous chase. Congratulations to those who saw tornadoes. I received a call from Dave Hoadley who saw the very nice tornado from Indian Nation Highway near Dustin. Thanks to Dave Hoadley who called me with weather information, Scott Blair for some navigation during one section of the chase, and The Chase Hotline for updates and especially radar information.

1P 2V 3V
4V 5V 6V
7V 8V 9V

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

Archived Weather Data (14Z and 15Z)

SPC outlooks SPC Day 1 graphic Tornado prob. Satellite image Satellite surface plot
Dewpoint Wind fields CAPE (CAPS) CAPE (ADAS) 500-hgt

Next Page: May 21, 2001

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