Panhandle Unchase

June 10, 2010 by · Comments Off on Panhandle Unchase
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Channing/Groom TX, 25 May 10

SHORT: Observed supercell get munched by outflow-dominant multicell complex NW of Amarillo. Pretty sunset.

This wasn’t specifically intended to be a chase day; but if we happened to see a decent storm along the way, that was acceptable! We had a truck bed full of cargo from Elke’s late mom that we were bringing home from DEN-OUN. Even though most of it was well-covered by plastic, getting in a bunch of rain and especially hail was not a palatable option. Therefore, even though the most dense concentration of convection promised to be along the Kansas segment of the dryline, where tornadic storms did occur, we opted to use the southern route through the Panhandles in hopes of more discrete activity.

We could see the first towers erupting along the dryline, early in the afternoon and to the distant E-ESE, while still on I-25 in southern Colorado. After turning ESE on US-87, a series of big towers grew into storms to our ENE and NE, including some of the Kansas activity that provided the joy of rich and abundant data to V.O.R.T.EX.-2 scientists. Near Des Moines (the New Mexico town, that is), we saw a classical, atom-bomb style of thunderhead eruption in the western Texas Panhandle, off to our SE (here photographed beyond one of the area’s numerous, inactive cinder cones). Given the favorable shear and discrete nature of this storm, its destiny as a supercell was assured, and our destiny was to intercept it — preferably avoiding most of the precip.

It took us a long time to get around to the E side of the slow-moving storm, even via the fairly direct CAO-DHT-Hartley route on US-87. As we approached DHT, radar imagery indicated that a left-split off of some storms N of Clovis was growing into a large, northward-moving multicell cluster — headed directly for our intensifying supercell! Just our stinkin’ luck! Tracking our course and that of the raging multicell cluster from hell, it was obvious the solitary supercell with so much potential would be snuffed out like a match in a fire hose, not long after we got in viewing position.

Our viewing position turned out to be virtually the same spot N of Channing from which Rich T and I first observed the tornadic Dumas-Stinnett supercell from 18 May. Unfortunately, this textured and colorful little storm was about to be absolutely destroyed by the onrushing wall of outflow and convection from its S. We had about 15 minutes of viewing as that happened, then headed to AMA.

There was too little daylight left to attempt to intercept Jeff Passner’s tornadic storm near Dimmit, so we stopped in AMA for dinner, drove E, photographed the Leaning Water Tower of Groom in some nicely reddening sunset light, then drove on home in the dark of night. So, in effect, we were able to observe the shortest-lived and most decidedly nontornadic supercell in between all the longer-lived, tornadic ones.

You Decide

June 2, 2010 by · 2 Comments
Filed under: Summary 

Dumas-Stinnett TX Supercell and Tornadoes, 18 May 10

SHORT: Witnessed intermittently tornadic supercell (specific tornado count uncertain) from NW of Channing TX to NE of Stinnett before losing it to darkness and a road void.

Rich Thompson and I (the Two Chumps) headed out of Norman with modest expectations for a dryline supercell chase day in the Texas Panhandle, given the “recycled” nature of the moisture (dew points in the 50s to near 60, left behind by prior convection over Oklahoma, though enticing levels of shear helped me to convince Rich that it was worthwhile to head west. Jack Beven linked up with is at Battlestar Norman for the trek out, following us in his rental car.

The storm of this day would exceed expectations, frustrate us, fascinate us, play hide-and-seek games with us, and flabbergast us in many ways, and overall, definitely was worth the trouble! You’ll soon understand why my efforts at photographic forensics has taken so long since, and why I’ll shamelessly borrow Fox News’ favorite slogan for some of the strange and mysterious phenomena we witnessed.

Our general target area was DHT, where we hung about a bit, and where several runs of the short-fuse HRRR had predicted a locus for 2-3 dominant late-afternoon supercells over the western and northern Panhandle. Foci for convective initiation seemed rather nebulous, except for the diffuse dryline far W of us near the NM mountains, and a confluence line with some cumuliform cloud enhancement to our near S.

Once some high clouds thinned enough over the confluence line, towers deepened rapidly, and the first storm of the day erupted merely 25-30 miles to our SSW. This seemed too easy — a rapidly intensifying storm in our general forecast area of the NW TX Panhandle.

We charted an intercept course between Hartley and Channing, and soon had a nice view of the young tempest’s already supercellular appearance (looking W from ~6 N Channing at 1658 CDT). Nearly continuous rumbles of thunder high up in the anvil and vault regions signaled essentially continuous zips of lightning, indicating an active ice-particle charge separation region and, along with its clearly supercellular inclinations, active generation of even bigger ice particles (namely damaging hail) aloft. This storm’s inner forward flank absorbed a growing cell originally to its S, and seemed fortified instead of handicapped by the encounter. It clearly wasn’t fooling around.

Content to let the storm churn along slowly toward us, and across the dissected scablands of the Canadian Breaks, we observed a few obvious (albeit scuddy) wall clouds and mesocyclonic occlusions, each with more sustained and well-defined low-level rotation than the previous. In this example (looking NW at 1722), behold the scuddy wall cloud at distant left, which was rotating with a well-developed clear slot cutting in front, while a newer, flatter, larger base and wall cloud formed at nearer right. The right circulation would become the dark, menacing photo you’ll see later (Dumas mesocyclone), while the one at left would persist for many miles and minutes, and yield our first unambiguous tornado.

By the time the newer mesocirculation passed US-385 just to our N and headed toward Dumas, we were ready to maneuver that way, when the older, more deeply occluded one tightened up rapidly, and began spinning like crazy. Cloud condensation reached most of the way groundward with and a funky little tail cloud at rear and dark shards of scud in the foreground for added spooky effect [looking NNW from 7 N Channing at 1734). Between that shot and this one, at 1735, a brief dust spinup occurred beneath, indicating the first tornado of the day (albeit cheesy). The low-level circulation crossed the road to our NNW without obvious dust or debris, then got partially rain-wrapped to our N and NNE. From within the murk appeared a very obvious, low-hanging condensation funnel with intermittent wisps of dust and condensation spinning at ground level beneath. Time of this undisputed tornado stage was 1744. Was this a second, separate tornado or an extension of the earlier one, the interval merely being too weak to be visually manifest? We report, you decide.

Atmospheric vortices aren’t always clean-cut, nor are they easily segregated from one another in tight, cleanly demarcated spectral bins. If the head-scratching already underway on weren’t enough, the remnant circulation moved farther ENE, away from us, wrapping in more rain, without obvious debris or condensation. Then…

What in the hell was this? Check out the enhanced version. Location of the feature was about 9 NNE of Channing, time 1749, still in that old meso that wouldn’t die. The scuddy, fat cone was rotating (not very fast); and instead of spinning up debris, was hoisting condensation off what looked like the SW edge of a bank of hail fog! Tornado or not? We report, you decide.

Tornado #1, (or was it 1.5 or 2 or 2.5 or 3?) duly documented, we bailed E along FM 722 to regain position abeam of the eastern (younger) mesocyclone. Stopping near Middlewell, we did just that, but found also a low-hanging pillar of condensation that intermittently extended to the ground from the old circulation, now to our NW (time 1757, see enhanced version). Another tornado? The same one? None at all? We report, you decide.

Finally, that area began to lose definition, and the separate, very obvious, big, intense, strongly rotating and probably tornadic eastern mesocyclone matured to our N (and about 7 WSW Dumas). Here’s an enhanced crop-n-zoom. It surely looks like there’s a condensation pillar in there, planted on the ground. Real or Memorex? We report, you decide.

The area of strong rotation began to fill in some with what looked like rain-wrapping condensation, toward the already well-warned burg of Dumas. We tried to get through and E of town before it did, but upon penetrating the starboard rim of the bear’s cage on the S side of town, wisely decided otherwise, and bailed back S. A tornado was reported in Dumas, though little damage was done (according to later reports). We had to go all the way down to Four Way, E to Lake Meredith and N on FM 1913 to TX-152, removed from good view of the storm’s rotational underbelly until this striking wide-angle scene 19 miles E of Dumas.

We headed a mile W and another half mile N on FM-1060 and let the storm, which had begun to accelerate eastward, move almost directly toward us. Meanwhile, dozens upon dozens of chase vehicles materialized on the roads all around, including what appeared to be the full V.O.R.T.EX.-2 fleet. Fortunately, unlike the next day, everyone we saw was well-behaved and the traffic did not impede either safe viewing or, when necessary, safe escape.

As we waited, a broad, ragged but very strong area of rotation cranked up at cloud base, a skirt of lowered cloud material orbiting the boundary-layer mesocirculation center at eye-popping speed, the inflow at our backs rapidly evolving from stiff breeze to assuredly severe levels. This transformation was amazing. We struggled to stand upright, my vehicle rocking in roaring inflow winds that whistled and jostled power lines overhead. The storm was doing what Erik Rasmussen once termed the “big suck,” a frequent harbinger of imminent tornadogenesis. We were confident it was about to plant the “big one” any minute.

Instead, it teased us with a small one, and not in the main merry-go-round either. At 1911, a funnel appeared under the rear (NW)-side tail cloud, at center in this 70-mm wide angle, a faint column sheathed near ground by dust and/or precip evident beneath in this enhanced crop-n-zoom. That “cheesenado” moved S and vanished quickly behind the increasingly precip-filled, spinning carnival ride of rain curtains and dust daubs orbiting the main circulation.

The blasting inflow winds subsided only when the rear-flank gust front approached our location, so we headed E on 152 toward Stinnett. Along the way, another faint but unmistakable dirt daub appeared near the leading edge, in the distant NNW, lasting 2-3 minutes. Look beyond the third fencepost from the left in this shot. It probably was just a gustnado, but at this point, who knew? How many tornadoes had we seen? You decide. By now we were certain only in our uncertainty. It would get no easier!

A more intensely rain-wrapped and turquoise hue fell over the storm scene as we stopped to view the storm from both a scenic overlook W of Stinnett and from TX-136 N of Stinnett. Flaunting a flash of comic cruelty, almost exactly between those shots, and as we were passing through town with no good view of the main mesocyclone area, the storm produced a visible cone funnel and brief tornado that some other observers saw from N of town.

Parked about 3 N Stinnett, a gigantic road void preventing the storm from being followed farther E, we let the main mesocyclone pass to our N and NE, hoping for a view into the circulating pillars of rain and hail from the SW or W. Meanwhile, as the rear-flank region passed over, a thin, snake-like funnel contorted itself in the turbulent, non-mesocyclonic cloud base less than a quarter mile to our W. Rich was on the passenger (E) side and didn’t see this, but I did alert him. Dying as it moved overhead, I felt as if it posed no appreciable danger, though Charles Edwards (who was to our S) drove up a few minutes later to let us know that he had seen the flanking-line funnel over us too, and was somewhat concerned for our welfare. It struck me as, at worst, a “Weaver walk-through”. A brief shot of hail up to 1.25 inch diameter passed across us also, visible in this shot as bridal veils of hailshafts cascading into the fields to our immediate SE.

Meanwhile, something very suspicious appeared behind the precip curtains, and in the area of rapid mesocyclonic rotation a few miles to our NE. What was that? Some nearby observers swore it was a rain-wrapped, multi-vortex tornado, and maybe it was. Here’s the enhanced version. Time was 2001.

We report…

As the whole area retreated off into the roadless prairie wilderness of the Canadian River valley, a more well-defined wall cloud appeared behind the precip (enhanced image), perhaps with some spinups beneath.

…You decide.

Whatever happens NE of Stinnett stays NE of Stinnett. 🙂 Actually, that’s not far from reality. That area is a vast, roadless tract of grass and scrub, on which even an aerial survey might not help forensically except for the most violent of tornadoes. We may never know for sure what was happening inside that furiously rotating cascade of hail and rain.

As we prepared to head S through Stinnett to find lodging in Pampa, we noticed that another, more ragged storm to our W had begun to rotate visibly at cloud base. It obviously was drawing in just enough unstable air for survival, from above or S of the shallow outflow boundary left by the big departing supercell. As the shrinking circulation passed to our N, with a ragged wall cloud, we did experience brief retreat of the boundary last us, and warm and moist S winds. This area merged with the W side of the bigger storm in that void, and in increasing darkness, while we high-tailed it to food and motel in Pampa.

Though pleased with our chase overall, and satisfied that this day did more than we expected with “recycled” moisture, we lamented that we could muster nothing more than brief spin-ups that were hard to see, and how on earth we ever could get a photogenic tornado to fill the camera lenses. Alas, thanks to family matters and work obligations, we were unable to chase on the days later in May, in SD and in the SE corner of CO, that provided many other storm observers with some of the most strikingly picturesque tornadoes documented this decade. Still, it was nearly cathartic to get out on the wide-open High Plains again, and a far bit less stressful than the unprecedented and dangerous circus of storm-viewing traffic that would dog us in OK the next day.

Easter Sunday Supercell along US-82

April 13, 2009 by · Comments Off on Easter Sunday Supercell along US-82
Filed under: Summary 

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.

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