2012 Season-Opening Success in Southwest Oklahoma
SW OK
18 Mar 12
SHORT: Intercepted merging storms then resulting single supercell over SW OK, with spectacular structure and three short-lived tornadoes.
LONG: A little advanced planning made possible a splendid start to the 2012 storm-intercept season, on the 87th anniversary of the Tri-State Tornado.
Before Tornadoes
My daughter Donna and I headed out from Battlestar Norman at 19 Z, thanks to 1) her outstanding academic performance and judicious spring-break homework planning that freed her this time to chase, 2) her ability to drive to meet me at work, and 3) Greg Dial’s swapping shift hours with me from the previous day. It was a good day for some dad-and-daughter time on the highways and byways of southwest Oklahoma. We targeted the LTS/CDS area, well-advertised for a few days as part of a corridor of dryline supercell potential.
Forecast thinking was that early cloud bases would be somewhat high, but storms likely being discrete given the presence of modest capping and decent component of mean-wind orthogonality relative to the dryline. Low-level and deep-layer shear would be more than sufficient. Boundary-layer moisture would increase as storms moved off the deeper mixed layer air of the dryline environment, deeper into a moist sector.
As we cruised W across the N side of Lawton (S edge of FSI), we started to experience promising breaks in the low clouds, while the first robust reflectivity echoes sprang up SW of CDS and E of Crosbyton. I immediately targeted the northern echo because it would be moving into: 1) the forecast target area, with a somewhat more favorable environment slightly sooner, and 2) a better road network over SW OK than for the storm headed to the Crowell area. Both of these would evolve into supercells eventually, along with a third echo farther S.
As we approached Hollis, the small, young storm came into view, still well to our SW near CDS. Being a softie for abandoned structures of the Great Plains, I couldn’t resist parking at a wondrously decrepit old house, located 3 E of Hollis.
The westward-listing relic of the homesteading era creaked in the wind, as if mournfully moaning some of the last words in its long and mysterious life story. A loose strip of sheet metal on its roof flapped hither and yon in the prairie wind, its clanking noise advertising the structure’s vulnerability for all to hear, but with only us listening. Yes, the old house was well worth shooting, both in its own right and as a foreground for the approaching storm.
Moving generally toward us, the storm became better organized, until distinctively supercellular bands and striations materialized. We repositioned a couple miles east to distance ourselves from the vault’s lightning production, while its base expanded. Another rotating storm formed just SW of the Hollis storm’s flank and moved NE, dumping its own front-flank precip into the back edge of the first storm.
Cloud-base spin began anyway, along with intermittent pockets of faster rotation and rising motion with lowerings (looking W). The first serious occlusion wrapped a good deal of precip around the low-level mesocyclone, with a short-lived, conical, rotating lowering that might be termed a ragged funnel cloud.
Meanwhile, as our gradually merging storm(s) got messier, things got very interesting 60-70 miles to our S. The classical, flying-eagle reflectivity appearance of the middle (Crowell) supercell tempted me enticingly, especially when the red polygon showed up. Despite that storm’s digital allure, we stuck with the northern storm based on visual cues, even through its struggles with mergers and resultant HP-like precip cycles.
Here’s why. The storms’ merger cast a lot of messy precip across the scene, but somehow didn’t kill the initial supercellular rotation area. We would stick to our original target. This was purely an “eyeballs” decision. On reflectivity animations it did look like a disorganized mess. Visually, it still was conducting a series of occlusions. Good thing I trusted my eyes more than radar this time!
While I’ve found wireless radar access generally to be a benefit in the years since its availability, this event was a fine example of how onboard radar access sometimes can be a curse instead of a blessing. When visibility sucks, and all you have to work with is radar, you go for the storm with the best organization, if the environments are somewhat similar. In this case, however, the nowcast environment also was a little better for the northern storm in terms of slightly weaker CINH, and similar to slightly stronger SRH in another 2-3 hours. It was a gamble of patience that paid off.
First, however, the messy, temporarily HP storm character brought down contrast (wide angle view looking NW) as the whole process churned northeastward. A new area of rotation developed ahead of the old, rain-wrapped circulation, as the storm(s) gained distance from us. It was time to reposition N and E through Shrewder. This meant going N six miles on a narrow but hard-packed dirt road if we were not to lose visibility. One stop W of Shrewder afforded us a view of a new and old meso with rainy pseudo-nado (looking NW). Meanwhile, that portion of the second (merging) storm that appended itself to the flank of the first began to exhibit some wild striations nearly overhead to the SW.
Upon seeing that, I knew the combined storm was evolving into a wedding-cake special, and we needed to get many miles farther NE to get enough of the storm in view for decent structure shots. We zigzagged through Russell and Mangum toward Brinkman, watching a couple more occlusions and short bursts of moderate cloud-base rotation. One stop near Russell afforded us this splendid view to the NW. We turned W from US-283 onto a paved road running S of Brinkman, looking SW toward the Reed area, and toward a stunning, sculpted supercell.
Tornadic Stages
While admiring the structure, I spotted something tubular emerging leftward (southward) from either within or behind a rain core under the base. Donna shouted over the wind, “Hey dad, is that a tornado?” I shouted back “Yes!” and managed to snap just one photo of the serpentine vortex (alas, with the 24-70 mm glass still attached…here’s a cropped version) before I reached into the car for the zoom lens. Time was 0004 Z. By the time I got the 300-mm lens on, the little tornado was gone, the area where it had been exhibiting only a scuddy lowering and some precip filaments. I don’t know how long the tornado existed before it popped out of the murk, but can’t imagine more than a minute or two. I called it in to the WFO, advising that the tornado had dissipated. [A couple of subsequent attempts to call during later events would be met with busy signals.]
Remarkably, this was Donna’s first tornado on a chase! She soon would add two more. Donna had been on 15-20 tornado-free storm intercepts with me over the years, and had seen three tornadoes while not chasing.
Staying in the same spot, we let the storm approach rather uneventfully, watching one more non-tornadic occlusion occur, then decided to head back east and gain more distance for structure shots. As I drove, Donna and I (she with direct sight, I via rear-view mirror) each noticed a smooth lowering forming in a somewhat rain-wrapped mesocyclone to the distant WNW. We turned around and pulled over at the first safe vantage, 5 E of Willow OK, right alongside Bruce Haynie and his chase partner Matt from LBB. The lowering was a funnel that rapidly became apparent as a tornado. Time was 0029 Z.
The condensation tube fattened into a tilted, tapered cone, while the clear slot eroded more ambient cloud material and a core dump grew to pseudo-tornadic form elsewhere in the mesocyclone area. A real tornado and a lookalike, all in the same view! Here was a 300-mm zoom at 0029 Z, seconds before the tornado appeared to dissipate.
Dense precip filled the entire mesocyclone below cloud base, and we started heading E again. We were just half a mile W of OK-6 and 7 N of Granite when another lowering showed up in the rain–tornado 3. This time, contrast was very poor, as was my attempt to photograph it (see deeply enhanced version). Time was 0039 Z.
Better vantages were had from both closer and farther away, and more to the NE. At this moment, I was located in that netherworld between close enough for a good shot of the tornado, and far enough to pull out structure. Sometimes a storm observer’s timing is off that way, but I’m not complaining…Donna got to see her third tornado of the day. Shortly after the tornado roped out (within a minute), we noticed a suspicious cloud lowering deeper into the precip, probably in an older occlusion. The feature was just too distant and low-contrast, beyond intervening trees, to determine its nature (severely enhanced crop).
Post-tornadic Period
On the way to Retrop, we stopped to view the majestic and now non-tornadic storm, exuding ghostly pastels in early twilight, here at wide angle looking NW with a mobile radar that wasn’t scanning. When we turned back onto OK-6 to head N, we saw that the radar truck was parked smack in the traffic lane–since then I’ve learned that they were broken down in that spot instead of stopped intentionally.
We stopped one last time, a few miles E of Retrop, to watch the storm go elevated and weaken in the deepening twilight. We were satisfied beyond measure with our first chase of the season, and fortunate to have experienced such a phenomenal storm with minimal hassle. We managed to avoid the worst of the chaser hordes, and saw generally safe behavior even in traffic.
Given the late hour by the time we reached the next sizable town (Cordell), celebratory steak dinner would have to wait until the next day. We did, however, enjoy some Sonic food, followed by a little more dad-and-daughter time on the couple hours’ drive back home.
[EDIT] Post-chase, I learned that my camera clock was 6 minutes slow. The clock has been reset, and the times above corrected.
A Real Stretch
Okeene and Karns, OK
23 May 11
SHORT: Observed small tornado W of Okeene OK and nontornadic supercell E of Greenfield OK.
LONG:
This “day before the day” heralded the beginning of the long-advertised “undercutting Pacific jet”, and impingement of a strong, broadly cyclonically curved upper wind max over the southwestern CONUS as a 500-mb cyclone closed over the Pacific NW. I much prefer patterns like this for observable supercells than closed, stationary to retreating northern-Plains lows like we had just seen.
A strongly difluent upper height pattern spread over the southern High Plains late in the afternoon with subtle height falls occurring across much of the region. The presence of a dryline that was
1. Beneath those height falls and
2. Bounding the west rim of a rich moist sector (at least over the TX portion)
…was a high-confidence scenario, the specifics being maxima in low-level lift versus strength of capping into evening.
Accordingly, Jack Beven and I, in caravan with DF’s “Dude, Three Chicks and a Dog” chase team, headed W on I-40 to await storm initiation along the dryline in a strongly heated and increasingly moist air mass.
Along with Howie Bluestein, Dan Dawson, Jeff Snyder and other scientists and students accompanying OU mobile radars, we waited and shopped at the Cherokee tribal store on I-40 near Calumet, until echoes appeared to our SW, W and NW. We parted with the OU crews, briefly stopped to watch some high-based junk SW of Watonga, then targeted the much more healthy Fairview/Okeene storm.
In fact, the storms SW of Watonga were everything but photogenic; and we still were in transit northward Okeene when we caught a view of a suspicious lowering under the emerging base W of Okeene. In a rare event for me, my first photos on this day therefore were of a tornado!
By 1618 CDT, when we pulled over along a section road 3 S Okeene, the lowering had become a well-defined funnel cloud about 5 NW of us or ~4 W Okeene. It was tilted nearly horizontally (wide-angle with foreground storm structure), and already tornadic based in dust-whirl reports by closer observers. Time was 1618 CDT. The newer updraft base almost overhead seemed to be the next candidate for a mesocyclone formation/occlusion process; but it actually moved N and got absorbed into the forward flank, vanishing in the process.
Meanwhile, we witnessed, photographed and reported the 6-minute tornado from the same vantage as a debris cloud became more and more apparent (unenhanced and super-enhanced photo). Shortly before the tornado dissipated, the debris cloud got displaced astonishingly far S of where the condensation funnel met the cloud base. Clearly the stretching term of the vorticity equation was at play here.
We stayed with the storm for about 45 more minutes just E of Okeene as another small thunderstorm formed to its S, moved over us with frog-strangling rain and closely slamming CGs, then merged into the main updraft region. This pathetic state of affairs left the supercell demolished as a discrete entity. What was left merged into a massive multicellular morass extending some 70 miles E-W across the area. Now what?
Onboard radar feeds tempted us intensely with displays of a solitary supercell about 75 miles to our S near Gotebo, and there was plenty of daylight to head down there and spend some quality time with that storm before dark. Off we went, photographing a smaller cell to our SSW over Watonga. (which would become the supercell E of Greenfield) and later a distant presentation of the convective mass we had left.
That Watonga storm looked rather innocuous as we passed under its early updraft base in and S of town. However, by the time we reached Greenfield and around to the S side, the convection grew explosively into a full-blown young supercell with bright, hard-looking updraft towers boiling up the back side. The upward eruption of the convection easily was visible in real-time via our eyeballs, as was the onset of helical turning in the midlevels, white turrets and cauliflower tops rocketing skyward and veering rightward like daddy likes to see.
We didn’t intercept this storm; it intercepted us. The supercell blossomed right besides us on the way S, in an environment not seeming too different from more mature supercell to which we had been aimed; so we diverted from plan, maneuvering the backroads NE of Karns into the near-inflow region of the Greenfield storm instead. Its first mesocyclonic occlusion attempt happened just to our NNW with a well-defined, if elongated, wall cloud that rotated only slowly. Rotation tightened considerably after the mesocyclone became deeply occluded, slotted and nearly cut-off from the rest of the storm, having been kicked way back out the NW side of the storm. Alas, loss of buoyancy overcame stretching; and the circulation perished.
After that, several areas of weak-moderate rotation materialized along an increasingly elongated cyclonic-shear and convergence zone; but the supercell itself was getting weaker and more strung out. We left it and headed S on US-81 through El Reno, once again headed for the initially intended supercell still a little over an hour S of us; but that storm died before we got past Tuttle. Little did Jack and I realize we were crossing the path that a certifiably violent and deadly wedge tornado would take the following day.
We enjoyed seeing Jim Leonard in the field as well as the aforementioned OU folks, and had a fine dinner in Norman with Matt Crowther, Betsy Abrams, Greg Stumpf, and my beautiful bride Elke, who couldn’t chase on this day. It was a fine and fitting end of the “day before the day” setup. What a wild, frightening, intense, and historic day the “day after the day before the day” would turn out to be…
At Long Last: Birthday Tornadoes
Hickory and Ada OK
21 May 11
Prologue:
This was my birthday. I never have seen a tornado on this date before this year, despite the seemingly ideal time of year for them.
Hold on! Tornado climatology isn’t always how it may seem. For strange cosmic reasons that shall remain a cryptic mystery, that date (green in the graph below) also is an inexplicable and pronounced low-day for tornadoes in the U.S. during this time of year, as shown by Chuck Doswell in one of his research papers published in the Electronic Journal of Severe Storms Meteorology.
Click to open an enlarged version:
The Intercept:
Elke and I headed S towards the northern rim of vigorous return-flow moisture near the Red River, followed by a unique chase team consisting of David Fogel, his cousins Samara and Ellie, and Ellie’s friend Ella, and of course DF’s equine-sized Leonberger dog, Porthos. [Note: This meant I was chasing with Elke, Ella and Ellie…good times!] Ellie and Ella were first-time chasers this day, giving me hope for some “rookie luck” to overcome my “birthday curse”.
Our target area was southern OK an north TX just E of the dryline, and we settled for the middle: The Red River, heading to GVT to fuel up and await nearby development near the northern nose of the most robust return-flow moisture. On the way down, messy supercells were evident in central TX, well S and Sw of the Metroplex and out of the target area; while a discrete storm rapidly intensified just SW of FTW. A convergence zone was evident in reflectivity imagery extending N from the FTW storm past ADM. This was our hot zone for hot action.
Not wanting to intercept a storm through the Metroplex if we could help it, we held firm at GVT awaiting closer development. That move paid off; as the FTW storm quickly (and rather inexplicably, given the strong buoyancy) perished.
After fueling and getting some technical difficulties fixed with DF’s onboard electronics, we waited a few miles N of town near I-35, admiring wildflowers and convective towers–yes, newly developed moist updrafts to our near WSW and more distant N. The northern towers, even through haze rendered by smoke from Yucatan crop-burning, looked healthier and began glaciating, as viewed across the verdant North Texas savanna. We had a storm to target, brother.
As we pulled onto the I-35 slab and headed N, strong reflectivity echoes started to appear NW of ADM. Those developed quickly into a strong echo, already resembling a supercell by the time we exited the slab and headed E on OK-53. Intense towers rolled up into the back side of the storm with fantastic buoyant force, as seen looking NE from W of Gene Autry.
Zigzagging E and N toward Sulphur, we met the first hilltop base view just in time to view a funnel suspended from an older, occluded mesocyclone to our NW (and W of town). By the time I could pull over safely, the rotation already weakened, the funnel more ragged and not as low, the clear slot cutting well around the cloud-base mesocyclone area.
Focus shifted to a newer area of cloud-base rotation to the E. The storm already was tornado-warned and had been for some time. That appeared justified. This supercell was moving into a very moist, low-LCL air mass with big (and growing) 0-1 km hodographs. This already was the most promising storm I had seen on a birthday, despite some unquestionable jackassery that ensued while viewing the newer mesocyclone area. None of the scuddy, rotating lowerings to our NNE (just E of Sulphur) could tighten up much, and the storm was getting away.
We needed to reposition, despite the lack of great vantages in that hilly and intermittently forested part of the state. Haze clearly was a problem too, and I knew we needed to be close to get better contrast. Before that area of storm-scale rotation could cycle back up, we headed through town. Our bright-eyed, twentysomething supercellular newbies from New Jersey, Ellie and Ella, got serenaded by the stereophonic wail of the Sulphur sirens, offering them an ominously palpable reminder of the menacing side of springtime in Oklahoma.
About halfway E on OK-7 to OK-1, the organization improved, all right. Obligingly, the storm that had been behaving itself during our relocation grew a very broad, extensive updraft base–all of which was rotating, and rather rapidly. Within the tumultuous gyre, every lowering was spinning in its own right, the whole system a seething, cloud-base cauldron of eddies and whirls that defied ready classification. We stopped 3 SSW of Hickory (and 1 W of the OK-1 intersection) to watch its merry-go-round of distinct funnels, shallow and bowl-shaped lowerings, and at least one brief tornado.
Some vortices were more than two miles apart, others adjacent. Where is the cutoff between a broad, multiple-vortex, weakly tornadic circulation, and a multiple-funnel (or multiple-tornado) area of storm-scale rotation? This thoroughly fascinating process unfolding to our NW through N blurred the lines between any such distinctions on the spectrum of atmospheric vortices. Sometimes, it’s just not as simple as categorically declaring tornado or not!
Two of the longer-lasting, lowest-extending condensation funnels (middle and left here, looking NW) initially developed apart at 1924 CDT, within the same mesocyclone. The eastern (right) funnel retrograded almost magnetically toward the western one, intertwining with it as in a seductive love dance. The combined condensation vortex then became more laminar, less scuddy, more wavy, and produced a brief, faint puff of dust beneath (deep crop-n-zoom/enhancement), in an area of very wet ground.
By 1926, the brief tornado was gone, the area of cloud-base rotation (at left in this shot) that had hosted the small, blended tornado vortex weakened. Did you notice anything to the slightly more distant right (NNW) in the last photo? Lo and behold, another area of rotation took shape to its NNE, itself offering a ragged, conical funnel that extended more than halfway down by 1927 CDT. If this was a tornado (couldn’t determine via enhancement or independent eyewitnesses), it was separate from the other, a circulation within a circulation within a circulation. These were far from the only funnels in the storm-scale gyre in just a 10-minute span. What a gloriously complicated mess!
The broader mesocyclone soon began tightening, and we needed to get E and N again to close in for more unambiguous tornado potential. In the process, we crossed a spot of infamy–the very railroad crossing where an agonizingly slow-moving train halted John Hart and I after we saw the distant Hickory tornado of 11 May 1992. That train 19 years ago seemed to go on forever, as the supercell got away, wrapped rain around its SW hook, and produced a multivortex F4 tornado just out of sight. Today, the tracks were clear and such agony didn’t befall us. The same road we couldn’t take way back then was open for business–right here, right now.
We turned NNE on OK-1 and drove almost under the rim of a (by now) very strongly rotating and more classical mesocyclone, stopping at a spot 1.5 SE Hickory when a broad cone funnel appeared about a mile to our NE. At 1934 CDT, a brief filament of whirling condensation rocketed up from the ground beneath the cone as I was exiting the vehicle, and before I could shoot…tornado! The condensation cone soon drew lower. Sinuous, partly translucent vortex filaments materialized beneath and coiled about one another, vaporous marionettes twirled by their tornadic puppet master. By 1927, the cone retreated to a smooth cloud-base bowl, and no vortices or debris could be seen beneath.
The mesocyclone began retreating NE, so we had to zigzag E and N to maintain view as it reorganized, retreated NNE somewhat, cut a deep clear slot, and intensified again. Heading E on unmarked road “E1700” 5 E of Hickory (a variably surfaced path of gravel, dirt and crumbling, antique pavement), we were very fortunate to find another high, relatively unobstructed vantage to our NNW and N.
Just in time, too…the mesocyclone cut a deep clear slot and began twirling funnels beneath with fervor (deeply enhanced crop). For a brief interlude, the spinning cloud mass dipped its southwestern margins into golden beams of sunshine, fluidly swirling together the concepts of atmospheric violence and beauty.
The circulation seemed to plant itself on the earth, chunks of scud forming right down to the ground, ripping across the surface at tornadic speeds, interspersed with intermittent but unmistakable suction vortices–one after another, none lasting more than a few seconds, but collectively, too many to count. This was a very low, humid, multiple-vortex carousel. Sometimes two vortices could be seen interacting while scud and/or suction spots whizzed through other areas of the magnificent maelstrom.
[Some described this tornadic stage as a “wedge”, but the condensation was too ragged, sparse and ephemeral to call it that. Still, if viewed with any blockage by trees or terrain, I can see how such a mistaken description could be made.]
The last evidence of a tornado was at 1953; thereafter the cloud base rotated much more weakly and rose in height. By now, we knew of the larger, newer and stronger supercell W of Ada, but the clearest path to it up US-377 still was blocked by our weakening (yet still potentially hail-bearing) storm.
After letting that supercell pass across the highway, we had a smooth trip to Ada, barely in time to see a conical lowering below the horizon (turned out to be the end stage of its last tornado at 2035 CDT) while still driving. By the time we found a place to stop, a small and ragged funnel remained. No matter, we could marvel at the spectacular storm structure spreading across the western sky. As this storm moved NW of Ada and began weakening, assorted precip shafts cascaded from the cloud base near low-hanging scud chunks, likely yielding any remaining “funnel” or “tornado” reports.
The short but happy drive back to Norman led to a delicious dinner, steak and shrimp for the menfolk, whatever the ladies wanted, kibbles for Porthos out in their vehicle, all in a festive celebration of a fantastic storm-observing day (and for me, the clinching win on the restaurant TVs that sent the Mavericks to the NBA finals). Birthday tornadoes that didn’t hurt anybody, great storm structure, Mavs clinch a playoff series…a great, great day indeed!