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.

Surfing the Wake of the USS Hailbomb

June 29, 2009 by · Comments Off on Surfing the Wake of the USS Hailbomb
Filed under: Summary, Uncategorized 

A Tale of Two Supercells
7 Jun 9
Pawnee City NEb, to Bethany MO

SHORT: Intercepted Pawnee City supercell for a spell, then failed in prolonged attempt to get around and ahead of the hail-heavy Oregon City/Savannah MO supercell. Interesting structure on both storms.

First off, we found out this day about the (non-weather related) road death in Iowa of storm observer Fabian Guerra. Though we didn’t know him, we offer condolences and sympathy to those who did. It was a simple but fatal deal of wrong-place/wrong-time that could happen to anybody who drives. Many of us in storm observing and outdoor photography have plowed into a deer (guilty here, twice) and/or swerved to avoid one, and simply were fortunate enough to maintain control of the vehicle and/or not have the animal come through the windshield. Never take tomorrow for granted!

As for the day’s chase… Elke and I headed for our target area of north central to NE KS — E to NE of the surface low and near the frontal zone. This was “synoptically evident” as they come, in the forecast sense; but mesoscale details (as often) threatened to mess up the chase day. Right as some of the best afternoon heating was about to take place, a thick plume of cirrus cast its deepening shadow overhead, an unwelcome visitor from above, wafted off a band of elevated, middle-level showers to our W and SW.

Despite this annoying development, no other area looked any better. Marysville, one of our favorite towns, seemed a good spot to wait for initiation, so we parked at the hilltop Wal-Mart for awhile in anticipation. The hail event the night before clearly was major, as shredded vegetation covered the ground throughout much of town, with windows broken in some houses and churches. DF and his cousin Samara (now the Two Fogels and Two Dogs chase team) joined us, as did a local spotter (Jamie) who followed us for a couple of hours.

Storms fired directly beneath the decaying remnants of the midlevel convection, in a short line segment from just NW of us (and over the NEb border) SSW to SW of Marysville. I’ll hypothesize that the cap, tremendously strong on the 12Z TOP RAOB, was weakened not only via columnar cooling related to large scale ascent, but also by evaporational cooling from above as the elevated, weak convection precipitated into the warm and dry capping layer.

One storm cluster — W of Pawnee City — seemed destined for good times, being on the boundary and in optimally backed flow; but it needed to shed the deleterious influence of junk storms to its immediate SSE. Meanwhile the tail-end storm (ahead of which we stayed for awhile) looked strung out and high based…a “wannabe” supercell. When the northern storm finally did lose its interfering garbage, it quickly acquired a deep meso and hook, so we targeted it. The tail-end storm fought disorganization for a couple hours, but would go on to become the V.O.R.T.EX.2-targeted Oregon City MO hailstorm.

Our Pawnee City storm gave us some good structure views through somewhat hazy skies, produced a few wall clouds (some weakly rotating), and even a nice RFD cut or two, but never could tighten up that well (wide-angle shot from 8 E Pawnee City, looking SW). We saw Chuck and Vickie amidst what he astutely termed the “cluster-f#&%” of chasers around that storm; there was so much traffic over a blind hill that I momentarily stood roadside to guide them into it.

Soon, the supercell began to get highly tilted and to shrink, while approaching the MO River, so we decided (perhaps a little too late) to leave it. Jamie the Marysville spotter, by then, left us to go home.

Meanwhile the southern storm, which we saw from earliest towers S of Marysville, suddenly was a somewhat sunlit eruption of thick, deep convection and anvil backshearing, beckoning longingly to us from its throne high in the southeastern sky. I never had much luck stern-chasing supercells in northern MO, given the hilly terrain, narrow and curvy roads, untimely towns and slow local traffic. Nonetheless, with a couple hours daylight left and some convincing from DF, we tried anyway…

Hard as we tried, with the river crossing and a tortuous maze of indirect, winding road options, we simply couldn’t get ahead of it without core-punching a rotating wall of hail that was visually apparent around the back of the hook. The hook seemed to park itself on every east road we wanted to take, right before we got there.

At one point near Union Star, a “bolt from the blue” struck less than half a mile to our S, several miles behind the hook and the flanking line. Less than twenty seconds later, we pulled over and I was outside shooting this image of a hailshaft on the backside of the supercell…but not for long, lest the storm recharge quickly and fling another supercharged bolt our way. DF and Samara must have thought I was nuts doing this just a couple of blinks after seeing Zeus’ pitchfork plow into the earth nearby. There was some risk, but probabilities were on my side if I didn’t linger too long out there.

While zigzagging constantly astern of the heavy frozen-cargo vessel USS Hailbomb, as if dolphins surfing back and forth through its wake, we indeed did see some huge stones (greater than baseball size or at least 3 inches diameter). The gorilla hail lay in the grass at Oregon MO amidst shredded vegetation, but we didn’t stop to measure due to the continuing chase.

We finally got near the back side of the hook near Maysville, taking decisive visual measure of a churning merry-go-round of rain and hail curtains orbiting some unseen circulation center to our immediate east. With tornado reports (even if they later turned out to be bogus “sheriffnadoes”) coming from inside that bear’s cage, we decided not to punch through. Instead, at sunset, we finally took the long way around, down to US-36 to Cameron and up I-35 a few miles toward Bethany, but still couldn’t get ahead. That’s when we waved the white flag and let the storm march off into the northern Missouri night.

Some attempts at lighting shots ensued (a decent but not outstanding one, and a better opportunity that I slightly overexposed, unfortunately), along with some conversation with Alnado there, and we headed back toward lodging at STJ. Along the way W on US 36, a dense flock of heavy storms developed atop the supercell’s outflow, coring us repeatedly with blinding rain and intermittent small hail.

A pretty decent chase day was capped off by finding a live brown recluse spider in our room at the Super 8 in St. Joseph (where Charles, Rocky, Bill Hark, Dave Lewison and other chasers also were staying). One of the girls staffing the front desk was frightened almost to panic by it. The other took it in stride, saying, “Oh yeah, we’ve got those all over our house.” At no point did either of them think to apologize or offer comps to this particular customer. I fed the fiddleback to a black widow spider from Oklahoma (my yard, specifically) that DF was carrying around as a sort of chase mascot this year. I also talked to a truck driver in the lobby who had lost all his window glass to what he estimated to be softball sized hail at Oregon City earlier in the day.