2012 Season-Opening Success in Southwest Oklahoma

March 21, 2012 by · 1 Comment
Filed under: Summary 

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.

Three States of Strangeness

July 6, 2010 by · 1 Comment
Filed under: Summary 

Slapout OK and vicinity
13 Jun 10

SHORT: Observed entire lifespan of supercell from SE of Dumas TX to near Coldwater KS including at least one tornado near Slapout OK. Also observed floods, beautiful clouds and bizarre cross-country cycling experience.

LONG: It was just another ordinary, ho-hum chase day with a rain-wrapped tornado to our south moving east, uncanny resemblances between the Texas Panhandle and the Everglades, a house propped up by a Frigidaire, and an Austrian bicyclist riding across the prairie to the beat of techno-dance music from a German-speaking mobile DJ. Nothing special or different here…

The strongest combination of moisture, instability, lift and shear was forecast along a segment of the former cold front (now gone quasistationary) from SW KS to the eastern TX Panhandle, dependent strongly on how far S storms could backbuild in a manner sufficiently discrete to permit cyclic mesocyclogenesis and greater potential for tornado development. The outflow-reinforced boundary lay from just S of Dumas to near Coldwater at 15Z, and wasn’t going to go far except where effectively shunted E by localized convective outflow pools. The 12Z AMA sounding had a very weak cap atop anomalously large dew points, with clearing skies, so early initiation (perhaps even before noon) was virtually certain.

After leaving our lodging, the question of the day became apparent:

Riddle: What do Chuck, Keith, Texas Beef, and Natural Gas have in common?

Answer: All are names of roads crossing TX-152 within 10 miles E of Dumas.

Heading E from Dumas toward the boundary, we saw towers already arising along it to our SSE by 1130 CDT (1630Z) — these would evolve into the eventual Perryton-Slapout area supercell. We got on the warm side of the boundary between Borger-Pampa, as the same towers deepened and glaciated to our NW. The chase was on, and it was only noon! The visit for fuel and burritos at a Pampa Allsups had to be succinct, so we could head N toward the projected storm target of Perryton.

Once back up out of the Canadian Breaks and atop the Caprock again, we found flooded fields everywhere from the wet spring, led by the previous day’s egregiously profuse rains. These cowboys S of Farnsworth had to herd their herd onto an island in what clearly wasn’t supposed to be a lake. Evapotranspiration was a given on this day! Every time I got out of the car — curiously, except near the tornado — mosquitoes descended in voracious plumes, bloodsucking varmints eager to draw sustenance from anything warm-blooded, and especially from storm observers. I wondered how many “skeeters” ended up advected into supercell updrafts and entombed in the cores of hailstones.

Our towers grew into a fuzzy supercell with a CAPE-starved appearance near Farnsworth, slightly behind the boundary. It probably was surace-based, but not in the best air mass at the time, but did exhibit occasional but not particularly strong cloud-base rotation from broad lowerings (looking NW).

Meanwhile, strong cells were firing back down between Dumas-Pampa again, which we easily could intercept if this supercell fizzled. Instead, updrafts continued to develop in a break between our activity and the southern convection, merging in with the rear flank of the nearby storm. It all remained rather disorganized for about an hour, backbuilding at a rate nearly equivalent to its translation up the boundary, but with a slight eastward net component toward Perryton. We headed S of Perryton and down a submerged US-83 before the storm reached the area. Trucks in front demonstrated the shallowest path through the dead-still water, and that the road remained intact beneath; this is where driving a high-clearance 4×4 pickup came in handy. Such positioning would get us into position to intercept the southern storms if this activity couldn’t get better organized, or if it did, to head E and N to stay with the original convection, without dealing with the town and nearby flooding again.

Our adjacent storm developed a large, sculpted shelf cloud, made even more scenic by the foreground of the huge flood S of town that I called Lake Perryton. The south side of the storm sported a classic shelf, while the N side still wanted to be a supercell, with a tail cloud and occasional, weakly- to non-rotating lowerings. None of this, land or sky, looked much like the High Plains that it was!

Most of all, this did not look like a storm that soon would produce tornadoes. I was getting impatient with it, but instead of bailing S forthwith, I moved a few miles away and examined an abandoned house S of town with an eye back to the N, while stiff, cold outflow winds pressed down adjacent wheat. Good thing we didn’t give up on the storm, too, as it started to look better-organized and more like a supercell again (wide-angle looking N over Perryton). Its own outflow had carved out a swath of convection-free air upshear, while SE winds to its SE maintained good storm-relative inflow. Looking N from SW of Booker, a very well-defined clear slot and wall cloud appeared, and we knew we had to keep this storm in our sights.

About 10 minutes after this shot, taken looking NW from just E of Booker, the mesocyclone region became rain-wrapped from our perspective, then immediately spawned the long-lived supercell’s first tornado, visible mostly to observers who buried themselves deep into the immediate mesocyclone area on muddy backroads. By then we were repositioning E, then N, to stay ahead of the storm.

Recognizing this as an evolving, tornadic HP situation where one needs to get tucked into the notch NE of the mesocirculation to have the best shot at seeing a tube, we set up shop on US-412, in the OK Panhandle, between Elmwood and Slapout. That road provided a ready east escape, an option not available last time I was in a similar situation (with Rich T on 19 May). While watching the accelerating supercell approach, we spotted and photographed another abandoned house, this one strongly dependent on an antique, rusty refrigerator for its survival! When that porch overhang goes, the rest of the structure won’t take long to follow it down into the weeds.

We moved uphill and N 1/2-mile, watching the storm approach. A partly rain-wrapped, rotating, bowl-shaped lowering appeared to our SW (wide-angle view at 1611 CDT/2111 Z, left side) that looked like it meant serious business. We needed to get back down to US-412 then uphill again to the E, in case that turned tornadic (it probably was already), and in case we had to make the great escape. On the way down, we spotted VOF Doswell roaming the grounds of the very same house, but didn’t have time to stop for idle chitchat.

Just after we climbed E and parked beside 412, a brief funnel and some diffuse multivortex filaments appeared under the lowering at 1616 CDT, just before I could shoot. Although the interceding, non-condensational stage lasted a few minutes afterward, I believe this was one continuous, tornadic circulation with the next stage, which manifest as a bulbous, tapering cone, then a well-defined and rain-wrapped cone with filamentous elements whirling beneath. By 1620 CDT the visible tornado became elongated, tapered, curved, narrower in appearance (normal and wide-angle views, by which time the tornado was to our S, moving E). We lost sight of the increasingly ill-defined tornado in wrapping rain to our SSE at 1622, by which time the onset of precip overhead (in the inner-notch region) compelled us to bail E on 412.

Now look at any of the wide-angle tornado shots and imagine the tornado away. What do you see? Otherwise, it looks like an outflow-dominant, rather junky storm organization with a big gust front and some pretty turquoise coloring on its N side. I’ve seen perhaps hundreds of similar-looking storms with no tornado wrapped in there behind the ragged shelf cloud; but in this case, there it was. And that’s all the supercell had left in a tornadic sense.

From then on, the storm’s successive mesocyclonic occlusions ingested excessive amounts of rain and outflow for tornadogenesis. We weren’t sure of this yet, of course; so we zigzagged N and E toward Laverne, meeting Howie along the way (action shot) and nearly getting struck by a staccato CG — the first among a sudden barrage that erupted immediately NE of the mesocyclone(s) in an area heretofore bereft of such a deadly menace. The bolt in question, which was so close I couldn’t tell the direction it hit, gave off an audible “snap” a split second before the simultaneous flash and slicing report of thunder. That momentarily disturbing sequence sent me leaping back into the vehicle glad to be alive and unharmed! I wonder if the snapping noise was the audible effect of a ground-up discharge from some close-by object that preceded the actual return stroke by a fraction of a second.

Shortly after Howie left and before encountering the CG, this shot revealed a dark, HP “stormzilla”. Notice the stubby, translucently rain-wrapped funnel at lower left, looking WSW from N of Slapout (heavily-enhanced crop-n-zoom). That highly suspicious protuberance emerged at 1640 CDT from some heavier precip. It also resided beneath a small, obviously rotating tail/collar feature rolling northward along the E face of the storm, toward a broader but weaker mesocirculation in the dark area to its right (N). We cannot be sure whether or not this was a brief tornado.

Those were the last shots we took from the storm’s inflow region. It started to gust out, merge with adjoining convection, and evolve a bowing feature as it headed for the area between Laverne and Coldwater KS, hot on our tail. With a central-northern plains target to reach in a couple of days, our minds turned to the potential photo ops on the backside of the complex, so we rushed up to Coldwater and let the northern part of the storm roll over us with likely-severe gusts and a barrage of subsevere hail. After the requisite inland-hurricane experience, we cruised WNW toward DDC for lodging and supper.

Along the way, we noticed a peculiar and wonderful combination of visual effects: underneath the MCS’ trailing anvil (not seen in the photo), laminarity along the top of the boundary layer, marked by a hazy delineation, and backdropped by pastel light from and through convective towers. Seldom have I witnessed such a combination, soothing in its beauty. Then things got [i]really strange.

As we stopped to watch and shoot that scene, a few miles SE of Ford KS, a distinctive male voice could be heard, slowly rising in volume. Elke asked me what I said; I hadn’t been talking. In a few more seconds, the source became apparent: a car slowly driving southeastbound toward us, on the shoulder of US-400, lights on, following a cyclist. The cyclist, dressed in skin-tight uniform covered with colorful sponsorship logos, rolled on past, followed closely by a car even more festooned in corporate logos. These, however, mostly were unrecognized ads, and the voice booming from the car’s loudspeakers was German! It was hard for Elke (a native German-speaker) to make out what he was saying, however, beneath the pounding beat of Euro-tech dance music also booming from the speakers. It was a rolling DJ, following a European cyclist across the Kansas prairie into the backside of an MCS!

We stopped in Ford, and right there at the convenience store was an RV parked, with many of the same logos as the weird cyclist/car tandem. Overcome by curiosity, Elke and I asked them (well, she did, since she spoke their language). The cyclist was from Austria — indeed, from the same general area as Salzburg, where Elke was born. He was riding across the USA from San Diego, and was only about 8 days into the trip. This means he had ridden well over 100 miles a day, including over the Mojave Desert and the mountains of southern Colorado. You have to respect that! They exchanged pleasantries, but seemed disappointed when she had to answer negatively to their question about where a good dinner could be found in town. For that, for them, it was either head back to Dodge or go all the way to Pratt…

After our own good dinner (a celebratory steak) in DDC, we parked on a hilltop W of town for a short-lived but gorgeous display of mammatus in the sunset light. The clouds glowed somewhere between champagne, iced tea and bronze on the spectrum of hues, and made for a marvelous conclusion to one of the more bizarre but enjoyable storm-intercept days in a long time.