Southwest Oklahoma Classic-HP Supercell

May 16, 2012 by
Filed under: Summary 

Hollis to Apache, OK
13 Apr 12

SHORT: Chase route GCK-LBL-HHF-LTS-OUN. Intercepted occasionally photogenic supercell from inception near Hollis to N of Duke, then as it got absorbed into what became an HP “Stormzilla” NE of LTS that crossed Wichita Mountains. Activity forming SW of that merged/absorbed it after dark N of Apache.

The day before turned into a storm-free “bustola” on the western Kansas dryline, with only distant convection to the north near sunset. Elke and I salvaged something from the 12th by heading to Monument Rocks for the late-afternoon light, then bunked down in GCK.

Today’s most straightforward storm intercept target was over the NW TX, SW OK and SE Panhandle region near CDS. We left GCK for a long but simple jaunt SSE down US-81, with lunch in Perryton. While there, storms already started firing over central and SW OK. Early initiation stinks, especially when the observer still is over 150 miles away!

A distant line of building convection hovered just above the SE horizon as we headed out of Perryton. Now we targeted the area of its prospective backbuilding into the slowly retreating late-afternoon dryline. The pre-dryline baroclinic zone upon which the storms were forming was supposed to retreat N also, after 21Z. My thinking was that the future western storms would represent the latest, highest-CAPE development, farthest removed from the threat of interference by upshear convection.

Given our distance and target area, we obviously missed the Norman tornado, not that we would have targeted specifically that needle-in-haystack HP supercell event anyway. As we reached Wellington, big towers began to backbuild on the pre-dryline boundary toward the Hollis-CDS area; so we turned E on US-63 into SW OK to get into position. We fueled up at Hollis as a young storm began rotating ESE of town, and newer convection with cores formed to our S-SW near Vernon and CDS.

Using phone radar, I noticed a nasty-looking hook had developed on the W side of Norman, with an HP supercell attached to a larger cluster of storms extending westward. It was a mess, but a mess with a meso. I called my daughter, who told me she just had experienced a tornado at the high school and had been safe in a windowless room, under a desk. The first concern, and relief, was that she was fine. My son was elsewhere, well SE of the path. Both were OK, so I could shake my head and marvel at the truth that, once again, a tornado had occurred in Norman with me observing other storms far away.

We cruised E out of Hollis, preliminarily targeting the storm to our ESE, but with a contingency to stop and let the newer development to our SW (then the tail-end conceptual target) come toward us if it started looking good. That’s exactly what happened. CGs from the newly organizing, tail-end convection slammed all around us between Hollis and Duke. We turned N out of Duke, found a good vantage 3 N of Duke, let the disorganizing eastern storm move away to our NE, and watched the newer storm approach and strengthen.

Alas, still more convection formed upshear, but the storm began looking distinctively supercellular as it crossed the section road to our W. This would become the Altus-Apache supercell, but not before producing a nice wall cloud, one with strong rising motion but only modest cyclonic turning. Another lowered area, likely from an older occlusion visible in the last windmill shot, loomed in the background.

Neither got any better organized; indeed, the entire storm started looking somewhat strung-out. We considered breaking off and heading toward the newer activity W of Hollis and W of CDS, as some others already were. However, we needed a pit stop in nearby LTS, while the supercell began turning into a dark, menacing, precip-filled mass to our N. We decided to stay with it for awhile, watching what by now was an HP “Stormzilla” over the western nubs of the Wichita Mountains.

Our supercell developed a nasty-looking HP hook on radar with a deep, intense mesocyclone; but we couldn’t see anything in the dark murk from LTS regarding the tornado report near Blair. Even without the bathroom break, I’m not sure we would have been able to get in position to see much.

By the time we reached Snyder, it was to late to do much with the western convection before dark. We also knew that the storm would head into an awkwardly configured road void in the Wichitas, cutting us off. [I had circumnavigated the void successfully last November 7, but from a different angle. That day, I beat the storm. This day, the storm would beat me.]

Driving several miles N out of Snyder, we hoped to see whatever the storm had to offer before it got into that road void. Here was its S side, along the rear-flank gust front looking W. Here was the E side, looking NNW toward a small but slowly rotating cloud protrusion with a clear slot. That looked interesting for a few minutes, until being undercut by a massive surge of the heavy precip-loaded RFD.

The photogenic HP storm moved off into the road void to our NE, and we knew it would be dark by the time we could get through Lawton and go N toward Apache to see the storm again. The storm produced a rainy twilight tornado during that interval when we were repositioning, fittingly enough.

By the time we reached Apache to see what was left, we found a storm still supercellular but again messy. Our viewing timing with respect to the best-organized stages simply wasn’t working out. At least, for a short time, the downshear anvil region sparked mightily and beautifully overhead. Our last decent wide-angle view of the storm, from a hill just E of town, featured the lights of the wind farm and Apache to our W, what was left of the wall cloud and main updraft region near center (NW), the vault area to the right (NNW), and of course, cows.

Before the storm could cut off itinerary options again, we headed NE toward Chickasha and home. The storm merged with convection to its W, evolving into a small bow, then moving over Chickasha and toward the Purcell/Pauls Valley area a weakening blob of rain and occasional hail. By then, we were home, tired from the two-day, thousand-mile trek, but eagerly anticipating the big severe-weather day of the 14th.


Comments are closed.