Easter Sunday Supercell along US-82
Wichita Falls to Gainesville TX
12 Apr 9
SHORT: Supercell intercepted from near SPS to Gainesville, severe hail measured, large evolutionary variations in storm character along with great structure witnessed and photographed.
LONG: I had been watching the next “cold-core” chase potential rather casually for a few days in advance, aware that it could be close at hand, but distracted by assorted diversions of life. Nonetheless, I had mentioned to Elke and my two teen-age kids that there could be some chase potential Sunday, and to be ready to head out with me, if desired. The kids do love to chase, and don’t get to do it much thanks to school, so they were hoping.
After Easter services, we went home, and I liked the narrow slot of clearing and heating that was occurring in VIS imagery, with only upper 50s to low 60s F surface temps needed to uncap the boundary layer, given such cold air and steep lapse rates aloft. Something loosely resembling an occluded front laid out near the Red River, arching NW across SW OK and into the SE part of the TX panhandle. Near and NE of that boundary, winds were backed; and to its W, surface winds were veered with very little SRH for most reasonable storm motions. A storm that formed in the clear slot would have to interact with that boundary to get happy and spin for a good while. We just needed a storm, and a favorable boundary-relative storm motion. Dew point depressions where there was decent heating and instability seemed a tad high for my taste; but when you’re off, it’s spring, and there’s a shot at a supercell nearby, then…go!
The storms probably wouldn’t be tornadic, but one could get lucky. At worst, with no meaningful storms, this would be a country Sunday drive and some family time, probably with some time hanging out in the Wichita Mountains. Given the very conditional nature of the event, to allow more room in the car, and because she had some work to do, Elke stayed home. I think she mildly regretted doing so after we (David, Donna and I) got back with some great chase stories and photos. 😉
We didn’t get to the Wichitas.
Breaking out of the grunge, mist and slop just N of FSI, we exited for gas and I dialed up satellite and radar on my I-Phone. Meanwhile, David and Donna helped a handicapped old man who was parked near us look for his lost car keys. His keys were found, and so was a necklace of reflectivity pearls on the radar scope, from near CDS ESE across the SPS area. While the cells SW of FDR would be closer and more convenient to intercept, the tail-end storm developing WSW of SPS would
1. Remain in the most unstable boundary layer air mass the longest,
2. Have unimpeded inflow, at least for awhile,
3. Remain closest to the larger gradient flows and stronger deep-layer shear vectors aloft (farther from the center of the vortex aloft), and
4. Have a great chance to interact with the boundary after maturity.
Such meteorological reasoning made the decision easy. We zoomed down I-44 through SPS, getting a visual on Tail-end Charlie by the time we got clear of the FSI area. From then on, I never needed the I-Phone radar app, but it helped in the early strategic decision, and I used it occasionally out of curiosity during stops, as time permitted.
While still in OK, the storm was visible from a long distance (>40 miles), with a high but robust cloud base, intermittent wall cloud-like lowerings next to or behind the translucent precip core, and a sharp anvil (sorry, no photos…driving on an interstate). We got through the SPS area and set up along FM-1954, 2 SE of Lakeside City, as the high-based storm (initially to our W over US-82) became somewhat more elongated, with a verticaly tilted base. This was the first of a few occasions when I thought the storm was losing organization, and that dinner might be imminent!
As the storm impinged upon our position, I headed E to the spillway area of Lake Arrowhead to watch it approach once more. The scene was beautiful, but the storm was very high based, with a skinny, shelf cloud-like appearance to the updraft region. We collected some dead mesquite (for my grill at home) and admired a long-abandoned trailer and boat (decal dated 1966!) while letting the storm go by to our N, across the SPS area and eastward toward Henrietta. As it was passing to our NNE, the E part of that elongated base broadened and thickened some, followed soon thereafter by a more HP supercell appearance. The storm did a small but intense core dump, complete with classical downburst rain foot, to our NE near Henrietta.
I followed the storm toward Henrietta, and after seeing the core get more translucent (looking ENE from 6 WSW of town), decided to penetrate it and maybe get some interesting late-day lighting under the other side of the base and shelf cloud. I asked the kids if they wanted to get into some hail (they have before, several times) and told them we might find some going through the “thin” core, since it was so cold aloft. Did we ever…
As we drove E into the precip (on US-82) it seemed to thicken considerably, as if another core dump was taking place. I expected lots of small hail, and maybe some technical-severe cheese, but this hail was nearly significant. A large amount of hailstones around an inch diameter pounded us as I pulled over right alongside the Montague County line sign, at its border with Clay County. David reached out and brought in several of the biggest stones, lumpy oblate spheroids that uniformly measured 1-3/8 inch on their long axes. I called this report in to WFO OUN, but it didn’t show up in the rough logs. [Estimates of larger sized hail came from nearby.]
The hail continued for a few miles past Ringgold and thinned near Belcherville…and man, did it ever get dark in that core for something that looked so benign when we were west of it. After we popped out the other side and pulled over, 3 W of Nocona, we saw why. Once again, it had reorganized, this time into a MUN (mean, ugly, nasty) monster, looking much like the prototypical north Texas HP Stormzilla, with a wall of scud roaring up the leading edge of the the outflow surge. And we had just gotten out before it became really intense. Whew!
Cows, placidly oblivious to the impending experience of hail bouncing off their skulls, grazed in the field as the supercell clawed onward toward us. We cruised E through Nocona, finally seeing a couple of chase vehicles (one belonging to a chaser that the kids and I know, Scott Peake, with whom we briefly spoke). I was mildly but pleasantly surprised at how few chasers were out there, especially considering I was on a major U.S. highway just ahead of what had become the only supercell in the region.
The road took a right turn more to the SE, and so did the storm — right into a hilly and more forested area of the Western Crosstimbers habitat, where good views would be hard to find. Fortunately, I stumbled upon a great westerly vantage about 3 NW of Saint Jo, at a roadside picnic area set atop a hill. We watched the storm from there for awhile (wide angle view). It actually shed some of its densely HP visual characteristics, acquiring more sculpted structure aloft and maintaining a convergent, slowly rotating wall cloud under the main updraft area. At no point did I see any cloud base accelerations that suggested imminent tornadogenesis, despite having a good view through zoom lenses; nonetheless, we observed it with keen vigilance for any rapid uptick in angular motion.
The storm then became somewhat less organized (wide angle view while lying in bluebonnets), but we stayed just ahead of it, aiming now for dinner in Gainesville and a ride home up I-35. With the ongoing loss of diurnal heating, I figured this would be the storm’s last hurrah. Still, it treated us to some spectacular twisting and banding (horizontal and vertical shots at 17 mm full-frame) between Saint Jo and Muenster. The last shot was deja-vu, in that it reminded me a lot of a wondrous scene that Elke and I witnessed a few years back outside of Hyannis NE — similar vertical banding, but without the residual supercell updraft at its southern root.
We ate dinner in Gainesville while the dying storm moved overhead, spitting a little lightning and rain, but not much else.
This was a fun, interesting and at times quite scenic intercept of a long-lived, non-tornadic “cold core” supercell in north TX. [Yes, I know there’s a tornado report by a local fire department in the rough log. I have seen no confirming evidence as yet. We had excellent views of the storm throughout that phase, and there were lots of hangy-downy scud foolers under the wall cloud at times. So I await unambiguous photos or video before believing the report.]
It was the best storm observing trip of the year yet, with hopes for many more! It also was a great dad-kids time. Last but not least, I ought to mention that Al Moller came to mind while I was belly-down in the bluebonnets, and those who know Al know why: It’s exactly the sort of scene he has specialized in shooting with amazing skill for a long time; but he’s got far better shots than that one in his slide collection.