Finally a successful chase for myself, Jeff Synder and Gabe Garfield for the 2006 season. I began to look to the day on the night before at the 0z run on 3/19. At first I was curious to see if there would be some action in the warm sector across ne Texas around the 18z timeframe. The more a looked at it, I didn't like the setup there. So just out of curiosity, I decided to take a look at the cold-core mini-supercell setup across Oklahoma.

I know relatively little about these setups, but with the little I learned last year from getting burnt on the dryline when others found tornadoes on cold-core setup, made me really think about the setup. So I woke up on the 20th and took a quick peak at the 12z model runs. The setup looked very classic. Closed 500hPa low sitting over the Ok panhandle with temps around -25C (very potent), stacked sfc low progged to move se through the afternoon, Td’s approaching 50F (little low for cold-core, but very cold temps aloft will compensate) and thin layer of lowlevel stratus that began to mix out rapidly so that we could get good insolation. We also had another key ingredient was the boundary interaction of the cf and wf that would serve as a focus point. The wf had pulled a richer area of theta-e and Td’s across nw Ok and this area was our focus as we took off. I used a paper by Davies and Guyer to understand coldcore setups a little better.

We headed out towards Clinton around 12:00pm to get some WIFI and lunch. While eating, we saw the towering Cu going up west of Clinton and threatnet had some echoes appearing. There were also some storms in sw Ok, but the sfc winds were veered down there, so the only area that had the possibility of seeing supercells (mini low-topped) was in nw Ok. So we targeted one cell that looked like it could remain discrete. With that cell in mind, we decided to get out ne of the cell right along the boundary. This would give us good visibility as it approached the lower lcl’s along the boundary. We got to the boundary about 30 minutes before the storm did, so we just sat on it and waited for the what now appeared to be a supercell to cross it. The storm cycled through a couple wall clouds. Then a very nice rfd started to cut right through the middle of the wall cloud. Here are some video grabs.





Once the rfd cut through the wall cloud, a funnel formed rather quickly. It persisted for several minutes before is finally got its act together and touched down. Here are some grabs of the sequence.









The tornado lasted roughly 2-3 minutes, while hitting a outbuilding and destroying a boat. The tornado lifted but the funnel persisted for 10-12 minutes about halfway to the ground. As the funnel persisted, another area of interest developed east of the tornado. The following pics show both funnels.



We pursued the storm east and ran into this. It felt cold enough that you would think it was snowing. They were shaped like hailstones, but soft, kind of sounded like somebody was throwing snowballs at you. You might call it graupel, I dunno though! All I know...it was weird!!!





All in all, I would rate this chase very high. What made it better was the fact that the SPC took out the tornado risk at the 20z outlook. That surprised me very much, but I was still very confident in the day producing a tornado. I believe that they were concentrating on the moderate risk area and overlooked the coldcore setup. It was also weird to chase in a heavy coat. The observation near us at the time of the tornado was 48F with a Td of 43F, it was very odd!!!! Also is was nice not seeing anyone else out chasing for once! Gabe summed it up nicely. "Hype was low, hope was high."