Second Dose of Beautiful Outflow Dominance
Filed under: Summary
Limon to Sheridan Lake and Lamar CO
17 June 11
SHORT: Intercepted two supercells that quickly became outflow-dominant in east-central CO. Picturesque structure. Nighttime lighting, mammatus and moonrise show near Lamar CO.
LONG: Starting at the laundromat in Yuma, we headed S at midday toward a forecast initiation area near the Palmer Divide, which by the time we hot the open plains S of town, already bubbled with tall convective towers. As in the previous day, I was concerned that storms would go too soon and create a big outflow surge; but instead they percolated for some time, struggling to organize as we approached LIC. There, we sat under the NE edge of a high-based, fuzzy, virga-spraying line of cells, none particularly impressive for about an hour.
Finally, as so often happens on these highest of the High Plains, a few distinct updraft bases materialized from the mush, one of more of which I guessed would evolve into a supercell, given both the favorable deep-layer shear and increasing low-level moisture content with time. When some of the virga started to reach ground as rain in LIC, we zipped several miles S of town then W a mile on a dead-end dirt road to watch the action unfold, while remaining in at least marginal phone-data coverage of LIC’s cellular towers. Turns out we didn’t need the data…as often is true out there, the eyes have it.
Two supercells developed essentially in sync — one to our somewhat distant W beyond Simla, the other to our NW between Matheson and LIC.
The closer storm evolved fast, and in fascinating ways. The initially broad, high updraft base in the last photo lowered somewhat, with a broad, ragged cigar of scud materializing beneath as the updraft began to process rain-cooled air from the neighboring parts of the forward-flank core. Notice, in the last photo, the lower-middle part of the scud bank seems to be rising off the ground. In fact, it not only was rising, but weakly rotating–before the broader scud stogie ever attached to the parent storm’s cloud base: a “scudnado” indeed! The scud mass kept growing and rising, becoming part of the storm’s updraft base and lowering it tremendously. This is a classic example of a storm modifying its own thermodynamic environment to ratchet down its own LCL!
Meanwhile, we saw intermittent chunks of ground-based scud, rising and slowly rotating. Nothing appeared too threatening from the standpoint of developing a real tornado, but it certainly kept my attention, in case the circulation ever started to tighten up to ominous levels. Some of them certainly had that look (zoom lens and enhanced digital zoom). I was pleasantly surprised and glad to see that nobody called these in as tornadoes, knowing that a lot of chasers were roaming about the area (based on Spotter Network icons). Another example a few moments later: (zoom lens and enhanced digital zoom).
The first supercell moved ENE over the LIC to our N, and gusted out. That turned our attention to the second (western or “Simla”) storm, which had sported intermittent, mostly non-rotating and ragged lowerings so far. A large, weakly rotating and precip-wrapping wall cloud developed as the storm drew closer, thanks to a a big mass of rain-cooled air entrained into the main updraft region. The supercell turned hard right, heading ESE and bearing the forward-flank core on course for the location where we comfortably had parked for about an hour. Time to head S again…
N of Punkin Center, we stopped to the updraft’s E again, this time for a short spell to photograph some beautiful clean-air storm structure. The supercell grew ever more outflow-dominant by the minute and accelerated its forward speed, so we couldn’t stay long. One more shot of the striking form of the storm, a marvelously textured swirl of gray shades and turquoise looming across the western sky, and it was time to bail over toward Aroya to open up some room between the storm and us. Along the way, its gust front briefly passed to the NE and to the N.
Approaching Aroya, we remembered a beautiful, old, abandoned schoolhouse we had seen on another chase nine years ago, having wished someday to photograph it before an approaching storm. This was our chance! The result is one of my favorite Great Plains scenery shots of the year so far.
Near Wild Horse, the supercell tried hard to enlarge a surface-based updraft, and appeared to succeed. The result was another spectacular display of texture and shading. Yes, that lowering at the inflow-outflow interface was rotating–slowly, but helically, giving me some concern for a brief tornadic spin-up. This one (zoom, and enhanced zoom of a zoom) compelled me to call, but thanks to being in one of the many tens of thousands of square miles of the Plains that constitutes AT&T’s 3% of America not served, I had no signal.
Fortunately, that feature quickly dissolved under relentless assault from cold outflow. Shortly after those shots, YF Umscheid motored up the dirt road toward us from a vantage closer to the feature, without reporting anything of consequence. We stayed ahead of the storm as it surfed outflow, driving E to Cheyenne Wells then S to Sheridan Lake. Between those burgs, we stopped to photograph the increasingly high, tiered, arcus-like eastern part of the base and a pretty array of sunset tones on the W side.
The storm now being a windbag and dust-bomb, we left it to get some lodging in LAA, setting us up for a long-desired revisit of Bent’s Fort and perhaps another chase opportunity the next afternoon off high terrain near and S of the Palmer. We found a nice, locally operated motel, then headed just SW of town to watch a short-lived, probably elevated supercell approach in the fading twilight. Elke was getting tired, so we went back to the motel, as the storm peppered town with abundant hail up to 1 inch in diameter (definitely smaller than the supposed “golfball hail” in the local storm reports).
A good lightning show beneath and on the back edge of the storm sent me back S of town again onto a different side road, this time to photograph the mammatus-festooned electrical show from the rear. As crickets and frogs sung loudly from every point of the compass, that amazing moist-earth smell refreshing my spirits amidst cool outflow air, the lace-lightning display continued with the storm’s eastward retreat. As a bonus wonderment, to cap a fine storm day, an orange moon rose beneath and then behind the distant updraft base. In the last shot, above the flanking line, you can see the anvil edge illuminated by the moonlight, in addition to the lighting by lightning within the storm.
After a long and satisfying chase day, we slept very soundly that night!
For your enjoyment, and as a reward for patiently reading this far, I’ve thrown together a couple of coarse animations from tripodded still-camera images shot that night: the first of the retreating storm with lace lightning, and the second of the wide-angle moonrise scene.
Beauty of Outflow Dominance
Nebraska Panhandle Bow Echo and NE Colorado Dry Downburst
16 June 11
SHORT: Fun day. Began in Hot Springs SD. Observed/photographed spectacular outflow-cloud structures (shelves, bands, stripes) with raging bow echo/haboob from BFF to N of SNY. Dropped S for peculiar, photogenic dust storm and sustained damaging gusts beneath high-based N rim of eastern CO MCS.
LONG: Back onto our storm-observing trek after a couple of amazing days in the Black Hills, flow aloft and at least marginal low-level moisture were beginning to juxtapose favorably once again to our south. We targeted the nearby Nebraska Panhandle for the prospect of high-based storms rolling east out of the higher terrain of eastern Wyoming. Browsing the morning maps, I was confident in upslope flow into that orography, along with afternoon storm initiation…but would there be too much, too soon, before the richer moisture could arrive in the evening? This scenario would mean outflow dominance.
Still, a conditional triple-point play in south-central KS was much too far away; and the mountains ain’t going anywhere. Blow increasingly moist air into them for enough time during daytime heating, and storms will form. Our goal: be downshear and see what evolves. High dew-point depressions portend shelf clouds, dust and high wind from storms; and sometimes that can be beautiful too.
And so it was…
We drove to favorite overlook SW of Angora upon which we had perched a few days before, watching the top 4/5 of assorted towers build and glaciate over the unseen mountains of eastern WY. Finally, when the storms started to coalesce and move off, one of which looked like an embedded supercell on radar, we headed W to the N edge of BFF to watch them roll downhill right at us. By then, the supercell was hard to distinguish in the onrushing wall of a dark, ominous, and increasingly well-defined squall line.
Reflectivity animations confirmed that the northern segment — basically due W of us, was bowing out. It was time to go outflow surfin’! Stay ahead of these, and they can offer some absolutely stunning cloud structures, such as the following three-piece view from between BFF and Minatare:
Looking NW: I’ve never seen a combination of lightness, darkness and radiating cirriform streamers like this before!
Looking W: Right into the teeth of Jaws. This is what a bonafide bow echo looks like when it’s “a-comin’ ta gitcha”. Check out the peculiar translucent strands, reminiscent of Silly String, festooning the otherwise featureless midlevel cloud deck. It might seem hard to photograph the strong dynamic range between the ink-dark core and the otherworldly apron of light above and beyond the shelf cloud; but not this time. This is how it actually looked, with no HDR bracketing necessary! I just had to meter for the area smack in the middle.
Looking SW: A classic view of an onrushing convective windstorm on the High Plains, this time with the Wildcat Hills lining the southwestern horizon.
We stayed ahead of the snapping maw of this storm — barely at time, I must admit — all the way to Bridgeport and beyond — before bailing S to let the road-deprived Sandhills have their turn at it. We got one last nice view of the atmospheric earth-mover raging to our NW before turning equatorward. What a gorgeous display of outflow-driven stormscapes we had witnessed!
Now it was time to get out of the way and figure out what to do with several more hours of daylight. Some storms had fired in NE CO, likely to be just as outflow-dominant and perhaps quite high-based. From SNY, it wasn’t that far away, and the next two days looked like potential Colorado storm targets anyway. As such, went back through Sterling again (retracing a good deal of our chase path from BFF three days before).
Unlike then, the Centennial State sky greeted us with a giant field of decaying storm material — virga dropping from various patches of agitation beneath a widespread anvil shield that once contained actual updrafts. N of Otis, a wall of wind slammed us in an impressive dry downburst, tearing dense channels of dust from plowed fields, buffeting the vehicle laterally with shot after shot of very localized wind-force lasting a second or so apiece, and making me struggle with the wheels to maintain positioning on the road. Good thing I had new tires for this season…
After a late rainbow and dinner at a familiar restaurant in Yuma, we bunked down there for the night, satisfied that we made the most out of a very windy storm day.
The human element of storm observing always has some interesting twists and turns too. We had a few loud neighbors at our motel, getting drunk and cussing in Spanish, and after a spell, I thought I might have to go out there and shut them up by request or otherwise. Fortunately for everybody, the former worked. The ringleader turned out to be cut from the cloth of my old barrio associates from long ago: he was wearing a shirt that said, in Spanish, “Don’t f___ with the DALLAS COWBOYS”. All day, I already had on my trusty blue-star cap. After some conversation about America’s Team, they retreated to their rooms, an elevated storm blew by with an intermittent show of close CGs, then off to bed everybody went.
Three States of Strangeness
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.