Birthday Supercells in Northwest Nebraska

June 9, 2010 by · 1 Comment
Filed under: Summary 

near Harrison, NE, 21 May 10

SHORT: Intercepted 4 supercells, 2 after dark, near Harrison NEb, with 2 funnels from twilight storm S of Harrison.

LONG:
My two main forecast areas on this day were in eastern Colorado, for any storms that could form and move ENE off the Front Range or eastward-extending ridges (Palmer and Cheyenne), and of course the classical upslope play into the Laramie Mountains. Since I began the day in Russell, the CO target was much closer, and more probable to reach by convective eruption time. The idea was to pass through, and if it looked dead, continue onward into SE Wyoming or Nebraska.

Unfortunately I got stuck at a long construction delay between Burlington and Wray, where US-385 is down to one lane with a pilot car driving 15-25 mph for about that many total miles. After getting out of that horrendous mess, I thought my Wyoming/Nebraska hopes were ruined, so I photographed an abandoned farmstead for a bit S of AKO, while waiting for storms to fire in northeast Colorado. The air mass kept looking too stable and stratified, and I gave up once storms E of the Laramie Range began to sustain themselves.

Unfortunately, because of the long intervening distance needed to intercept the resulting supercell, I never made it to the Wyoming phase of its life cycle, when the structure was best. Instead I cruised N from Mitchell on NE-29 to get ahead of the storm, knowing it would be moving into gradually more stable air. A portion of the legitimately scientific V.O.R.T.EX.-2 fleet came up 29 right behind me, along with some pseudo-scientific vehicle with a bogus-looking “TORNADO AND HURRICANE RESEARCH” sticker prominently plastered thereupon. I felt like stopping to ask the “TORNADO AND HURRICANE RESEARCH” crew what papers they’ve published with their “RESEARCH”, but knew the answer, and more importantly, had better things to do — namely, observe the supercell.

Lightning activity above me, in the anvil, was increasing, so I got back in my vehicle. Not a minute after I did, I happened to spot a CG hit within less then 50 feet of that “RESEARCH” vehicle, and about half a mile downhill from me! It even looked like the lightning might have hit them. I started the truck and was throwing it into gear to rush to their aid, when they abruptly pulled out of their spot and zoomed southward past me. It was a very fortunate thing none of them got struck! One of these days, however, under less atmospheric duress, I intend to query such crews in the field and find out about the nature of their “RESEARCH” publications. Anyway…

This shot fairly well represents my view of the old Torrington storm as it scooted across the border into Nebraska. At times it did develop weakly rotating, scuddy wall clouds, but its encroachment upon more stable air yielded the expected result with time ( here shown as a higher, flatter wall cloud with precip-filled occlusion-downdraft slot, behind a sticknet). That storm moved N and NE of me, and I prepared to head to Harrison to look for lodging.

Meanwhile, I parked for a spell to listen to the cheerful choruses of western meadowlarks and breathe the refreshingly rain-cooled High Plains air behind the first storm. V2 left the area, and in the twilight, a new, small supercell formed along or just a shade N of the outflow from the other one, SW of Harrison and about 15 miles to my WNW.

Rather quickly, some cloud-base rotation and lowerings developed under a broad, elongated updraft area, followed in quick succession by a skinny, scuddy funnel (deeply enhanced crop-n-zoom) and then a lower, more robust-looking and separate funnel (enhanced crop-n-zoom). Both of those funnels were quite transient, and I could not detect any dust or debris at the level of the (wet) ground beneath. If either was a brief tornado, it was too weak and short-lived to count as such, so I probably still haven’t seen a tornado on my birthday. Still, I’m glad to have had the experience.

The twilight supercell moved too deeply into rain-cooled air left behind by the first, and weakened considerably. I got a room at the only motel in Harrison — the Sage Motel, a friendly if rather forlorn and cramped place — and called Elke and my kids. One highlight of the day was my daughter and her friends singing “Happy Birthday” to me as a quartet serenade!

Meanwhile, two new supercells popped up in Wyoming, SW of town, headed that way! After getting off the phone, I wandered a few miles W of town to watch the nocturnal supercell pair move quickly past, their structures faintly illuminated at times by in-cloud lightning. I attempted photography, but it was just too dark out there, the lightning too faint. The rear-flank precip core of the second storm hit Harrison, but without severe wind or hail.

I had to be in Denver the following night to meet Elke and prepare for her mom’s public memorial on Sunday the 22nd, so the potential (and realized!) major tornado day in northeastern SD was too far for me to chase. Instead, on the 22nd, I photographed morning fog in the Pine Ridge area N of town, then drove from Harrison to DEN, stopping for a pleasant hike and photography excursion Agate Fossil Beds National Monument along the way. Meanwhile the ultimate tornado-feast was about to begin for other chasers 250-300 miles to my NE.

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.

LONG:
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.

Supercell South of Woodward

May 13, 2010 by · Comments Off on Supercell South of Woodward
Filed under: Summary 

Briefly Tornadic (11 May 10)

SHORT: Intercepted brief storm attempt W of Cordell and briefly tornadic supercell S of Woodward.

LONG: Ryan, Corey and I trekked out again on the “day after the day” with hopes of finding a tornadic supercell somewhere near the remnant frontal zone, which was retreating north as a warm front across western OK, or the dryline not far to its S. Deep-layer shear would be more than sufficient to support this potential anywhere along or S of the warm front, and the frontal zone itself promised backed flow, maximized boundary layer vorticity and enhanced low-level SRH for any storm that could form along it, or the nearby dryline and interact with the front. A stout cap and more nebulous low-level forcing yielded considerable uncertainty for this day, which was reflected in the justifiably low unconditional tornado probabilities in early outlooks. Compared to the frantic racetrack nature of storms the day before, one advantage would be cell motions far more manageably interceptable.

We waited a long time at Clinton, watching the warm front pass to our N and gradually deepening Cu in the warm sector. With little of note happening along the warm front or its intersection with the dryline, we took a look at a short-lived Cb that erupted not far away, S of I-40 and W of Cordell. Disturbingly skinny, the updraft seemed to suffer from too much dry entrainment, and left behind an orphan anvil. We only messed with this briefly before hastening back up to the warm front to await any chance of diurnal initiation.

We passed the warm front near Leedey and sat at an overlook near Camargo, one apparently prized by the research community for its utility as well! Shortly afterward, a V.O.R.T.EX.-2 radar truck appeared, their occupants wishing to use our parking space to set up surveillance for the nascent storms bubbling along the front to our W. We were pleased to oblige, and I had some enjoyable conversation with a few of its occupants from NSSL (Kim Elmore driving, Conrad Zeigler and Gabe Garfield onboard).

We had sustained, deep-convective initiation, at long last…8 o’clock magic! The more distant young anvil in the previous shot became the easternmost of a storm pair in short order, and was targeted by the field project. Meanwhile, we instead targeted the more vigorous young storm to its immediate W, blasting W on US-60 from Vici and ignoring the crappy-looking eastern storm. Even though we got on it early in its lifespan, we still were almost too late! The western storm went from barely having a radar signature to a strong mesocyclonic couplet in just a few volume scans. While going rollercoaster-like through hills W of Vici, we began to see the distant base(s) of that more distant storm, as it interacted with the vorticity-laden environment of the warm-frontal zone.

The more distant of its two main bases — already deeply occluded, suddenly spawned a brief, fuzzy, but obvious condensation funnel that fleetingly made ground contact off to our distant WNW. The tornado was at 2025 CDT in SW Woodward County, N of Harmon. We were driving westward in a remote, somewhat hilly area with no AT&T service, about 7-8 miles W of Vici (pronounced Vy-sigh) at the time, and the tornado was gone before we could find a place to pull over and shoot, so…no photos. However, scanning StormTrack, I found one photo of it from C.D. Collura…
http://www.sky-chaser.com/image/mwcl2010/m11tor3.jpg
…which definitely was our tornado.

I did call it to the WFO in a few minutes later when we were in a window of some cell coverage. Unfortunately I had trouble giving a specific tornado location because my road atlas was falling apart in my hands as I was trying to call and while we were driving, with pages falling everywhere! By then of course the storm had cycled another (non-tornadic) occlusion, and had a cold, fuzzy, increasingly elevated look (also mentioned on the phone). That “cheeznado” was the storm’s first, last and only hurrah in that regard — truly, a needle in the haystack that shockingly few of the numerous storm observers chasers in the area appear to have witnessed. It would have been easy to miss. By the time we found a safe and closer pull-off, the old occlusion was decaying further (left, in this photo, looking NW-N), while the new mesocyclone (at right) never could tighten up enough, and had a colder, more stable appearance.

By the time we got back E to Vici and N again toward Woodward, we began to see some great structure in fading twilight, but most of the colors that other chasers (who had been farther E) photographed so well were about gone. We ate a late Arby’s dinner in Woodward with two Environment Canada meteorologists (Neil Taylor and Dave Sills) and Matt Crowther, then headed back on the long drive home.

Next Page »