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Storm Chase: March 30, 2008

Today was the first "real" chase of the season...or at least that's what we decided to call it. Craig, David, and I targeted north-central Oklahoma and decided to go after the triple point. Forcing was rather week today, as can be seen in the following 500 mb SPC mesoanalysis at 1900 Z.

There was a nice tongue of mositure creeping into north-central Oklahoma, with clearing to the west, which was reflected in the 1900 Z surface temperature fields.

Per the 2:40 pm CDT mesonet obs, winds at the surface were much more backed to the north and northwest of OKC.

Naturally, at 2000 Z, the 0-3 km Storm Relative Helicity had a local maxima in that region.

In addition, there was a bullseye of frontogenesis over north-central Oklahoma.

Given all this information, it was pretty clear that we had to target north-central Oklahoma. If anything were fire to the west due to stronger daytime heating, it wouldn't do anything until it moved into the more favorable shear and Td environment. We fueled in Hennessey, OK, then set up camp in a field just southeast of there in extreme western Logan County. Craig, David, and I took turns throwing a softball around while waiting for data updates and periodically scanning the skies. The Cu field was rather poor, with convective towers attempting to break through but failing miserably. At 2115 Z, the visible satellite image showed us in the Cu field just to the west of the overcast.

We knew that this was the farthest east we would want to be that day, so we were fully prepared to have to move west. However, we did not think that storms farther west would do anything given the lower Td's and shear. In fact, we admittedly mocked the British exchange students for going way out west to Clinton, OK. After much more waiting, with no more clues from the sky as to where storms were going to initiate, I looked up, and saw this...

Yes, Mother Nature was giving us the finger.

Again, at 2200 Z, there was nothing in the surface pressure, wind, pressure tedency, and moisture convergence fields that indicated that we should relocate. In fact, we were right in the region of greatest moisture convergence. So we continued to wait.



MLCAPE was a bit higher to our south and west, but with lower moisture, we didn't think that would be of much importance.

We were wrong.

Shortly before 2300 Z, two storm cells broke through the cap in southwest Oklahoma and RAPIDLY acquired rotation. By 2315 Z, nice anvils and overshooting tops could be seen in the visible satellite signature.

After much debate, we decided to give up on our initial target location (not usually a good idea, but this time, it work in our favor) and fly southwest towards the storms. There was not going to be much daylight left, so we thought we had nothing to lose. Sure enough, nothing formed in north-central Oklahoma that day despite our best judgement. Suffice it to say that meteorology is a rather humbling science. You never know when Mother Nature will slap you in the face. Anyone who has an ego and thinks he or she is an "expert" in the field will eventually be proven wrong by the natural world.

In response to the rapid initiation of supercellular convection, the SPC issued a tornado watch for western Oklahoma.

At 6:27 pm CDT, we were still in southwest Kingfisher County, but heading southwest toward the storms as quickly as possible. The ultimate irony of the day: Clinton, OK was the place to be!

The northernmost cell had split by this time, and we made the decision to go after the right-split. The left-split moved roughly due north, and emerged ahead of the cluster of storms. The right-split moved east-northeast. As we drove southwest to meet the storms, our first sight was the anvil and updraft tower of the left-split, nicely backlit by the setting sun.

As we continued, we came underneath the anvil of the right-split, which put on a spectacular mammatus show!

This was a good sign! We continued onward, determined to catch sight of the base of the right-split storm before dark. Southwest of this storm, there was an HP supercell that was the oldest one of the cluster, but we decided not to pursue it because time was of the essence. We positioned ourselves near Eakly, OK at 7:44 pm CDT, just southeast of our right-split storm, and northeast of the HP.

The SRV display from the same volume scan showed nice mesocyclone signatures on both cells.

We were in perfect position to intercept our right-split storm, but we could not help but stop, step outside the car, and admire the most spectacular view of a supercell backlit by the sunset over the rolling plains. We were surrounded by nothing except open farmland, grazing cattle, and a supercell; mesocyclone hanging gracefully in the distance. Turning around, I saw a family standing in their backyard, overlooking the farm, parents holding their children by the hand, watching the Mothership roll through their land. I wonder if they understood what they were seeing.

Peering to the southwest was what looked like a funnel cloud hanging from the HP storm, but it lasted for only a brief moment. The structure of that storm was not too impressive, so we decided to stay with our right-split.

We moved a little bit farther north, then stood there for at least fifteen minutes, admiring the beautiful work of art that Mother Nature had sculpted, slowly drifting across the plains in front of us. Lightning crawled its way through the underside of the cumulonimbus cloud, while cloud-to-ground strikes flashed intermittently. Constant rumbles of thunder rolled across the landscape.

As dusk approached, the lightning increased in frequency, and we sought safety inside our car, still watching the beast as it gained strength. LCL's were still rather high, but they were gradually lowering. We had come to terms with the fact that if the storm were to produce a tornado, it would do so after dark, so instead, we just watched the storm from the distance.

Here is a time-lapse of what we saw over the course of those few minutes. Storm motions were slow, so we were able to navigate around the storms with ease.

Right before the end of civil twilight, we moved closer to the base of the storm, so that were directly adjacent to the mesocyclone.

The gracefulness of the supercell earlier had turned to violence, with constant cloud-to-ground lightning strikes surrounding us. The crackle and crash of the thunder was deafening. We stayed in the relative shelter of our car, watching the growing mesocyclone ahead of us. The ominous Mothership was backlit by lightning. With caution, I rushed outside for a brief moment to set up my camera and managed to capture this moment on film.

We did not stay in our position long, as we realized that the equally monstrous HP supercell to the southwest was gradually bearing down on us. We quickly enacted our escape plan that took us south and east to clear its path. It was interesting to note that the left-split storm that we had seen several hours in advance had continued north and by 8:43 pm CDT, was near Fairview, OK!

By 8:57 pm CDT, we cleared the danger zone in the vicinity of Binger, OK. We continued east. Notice that a third supercell had formed behind the two that surrounded us. A tornado warning was finally issued for the southernmost storm.

As we left the supercells, I turned my attention to helping several other students who did not have radar data on the road. The Brits had found themselves BEHIND both of the supercells we had seen earlier, and AHEAD of the third supercell that had formed. I instructed them to get as far north as they could as quickly as possible. They made it to the town of Weatherford, OK just in time, right before the arrival of the third supercell with the dangerously large hail (radar estimated likely 3"+ diameter). By then, the supercell we had watched earlier (the one to the northeast), had dissipated and was absorbed by the third supercell to the west.

These two tornado-warned cells continued just slightly north of due east, and threatened to wreak havoc in the Oklahoma City metro area. The most easterly cell was the longest-lived, since it was the first storm to develop earlier that afternoon. It maintained its circulation for over five hours. I received a call from other students from OU who were out chasing, and I routed them away from the storm as quickly as possible. They had found themselves right behind the mesocyclone of the easternmost supercell, and they witnessed power flashes ahead of them.

We made it back to Norman for a late dinner at Sonic, then drove back out to Hwy 9 to watch the supercells approach the metro area. By this time, we were exhausted and rather concerned for the residents of Oklahoma City. Normally, we would be excited to see such storms, but we were truly afraid for the potentially devastating scenario that was about to unfold. We kept hoping for the storms to dissipate with each volume scan of the radar. Finally, after over an hour of waiting, the first storm gradually lost its circulation and was absorbed into the supercell farther west. That one continued onwards for a bit longer, but then after midnight, it also weakened right before entering the Oklahoma City limits (thankfully!).