Thunder Basin Thunder
Ogallala, Thunder Basin and Buffalo Gap National Grasslands (NE/WY/SD)
17 Jun 13
SHORT: Early elevated storm CDR, back-of-MCS mammatus show eastern WY.
LONG:
BANG! That was how our day started, as a very close lightning strike awoke us from slumber in our motel room. Elevated storms had been rumbling overhead for some time during the early daylight period, their rain pattering a stay-asleep-please lullaby outside; but that vicious blast on the trailing side of it all was a literal eye-opener. [During a later visit to CDR, we found out from the motel proprietors that the strike split a tree in half about a block from there.] I PINGed the rain, of course.
Anticipating that any storm potential on this day would be roughly on the way between CDR and our intended destination of Buffalo WY, Elke and I started the day with a short driving tour of CDR that we have been wanting to do for years, then saw another long-desired destination there: the Mari Sandoz High Plains Heritage Center at Chadron State College. Though small, the museum was well worthwhile–a great tribute to the life of the High Plains pioneer writer and documentation of the hardscrabble life she and her parents led in settling the Sandhills.
Leaving the museum, we saw the sun peek out but also heard distant rumblings to the W. A small, elevated thunderstorm was riding the top of the outflow pool from the morning convection. While Elke gathered some supplies at Wal-Mart, I found a nearby hilltop from which to enjoy the view. The verdant prairies of a Nebraska Panhandle springtime can make even an ordinary, elevated storm seem majestic and beautiful! We ate lunch from that hillside Country Kitchen with the grand SW view, then hit the road NW into the SW corner of SD.
Forcing for deep convection appeared rather muddled on this day, with marginal shear for supercells. Still, with…
- A weak cap in modified UNR sounding,
- An outflow boundary from the morning storms arching back across eastern WY to our SW and W,
- Orographic features in the form of Black Hills and Bighorn Mountains looming to the NW and NNW, and
- Prospects for strong and sustained insolation…
…we had good cause to expect seeing a storm at some point this day. We planned to dabble in whatever convective pleasures the atmosphere offered, then settle into Buffalo for the night with a trip through the Bighorns planned day-2 and some Montana chasing on the docket day-3. Only a few days out of Norman, our Oklahoma home nonetheless seemed so far away and long ago as we trekked across the grand vistas of the northern High Plains and around the SW rim of the Black Hills.
Visiting the adjoining Ogallala (NEb) and Buffalo Gap (SD) National Grasslands for a spell, we did some short hikes over the wide-open Plains, dodging flowering cacti while watching persistent but non-deepening high-based convective towers to our SW, over WY and along the boundary. In the distance, convection built over the Black Hills and small, fuzzy anvils started to spread off the eastern slopes of the Bighorns.
We zigzagged the mixture of paved and unpaved roads characteristic of southwestern Fall River County, skirting just close enough to the Black Hills convection to see that it was rather high-based, poorly organized, incipiently outflow-dominant and unlikely to survive in any chase-worthy form after peeling out of the hills. Meanwhile, the persistent towers to our SW stayed about the same height they had been for two hours, and the anvils got enticingly dark and thick to our W. A check of radar during a brief data-availability interlude, however, revealed a very messy multicell-supercell clustered structure that was starting to accelerate SSE across WY and surf its own outflow.
Rather than make a mad run 100 or more miles to our S to get ahead of the charging convective mess, while adding 4-6 hours to the journey to get near or past CYS (and well out of our way) then back up, we decided to take a more leisurely approach. We remained on the planned westerly track, let the growing convective mass gather its cold pool and pass off to our SW, then slip in behind its bowing forces of rampage and see what storm light would greet us. This choice didn’t disappoint!
Appropriately named on this day, the Thunder Basin National Grassland hosted a spectacular display of mammatus (looking overhead at first, then toward the S). The amazing mammatus field evolved into sinuous forms resembling pods of swimming marine mammals (view with landscape foreground), as it moved fairly rapidly southward across the open rangeland apace with the parent MCS that, by this time, was blasting parts of SE WY with no mercy whatsoever.
We stood in cool outflow air, thoroughly immersed in the resplendent scene passing off toward the southern horizon, until sunshine came out and limited contrast. Once the convection and mammatus departed, so did we, shuffling off to Buffalo–Wyoming that is, via Gillette and I-90. A fine dinner in town and a day in the Bighorns area lay ahead.
===========
Our PING trail for this day.
Long Storm Day, Amazing Storm Night
NE Colorado and SW Nebraska
19 June 11
SHORT: Observed high-based, nondescript storms in eastern Colorado, pretty supercell that got undercut by outflow NW of Wray, and messy CL-HP storm between Benkelman-MCK-Cambridge NE. Spectacular nighttime lightning and storm-structure show at Alma NE with two supercells.
LONG: Starting the day in ITR, we had a pick of two nearly equidistant targets, both in very favorable shear for supercells:
1. The higher terrain of central Colorado to our W, more certain for initiation and more moist than yesterday.
2. An outflow boundary over SW Nebraska and NW Kansas, loaded with right moisture but also uncertain on position and timing of storm potential, if any.
The decision was tough. After looking at observational data of many kinds, I still was undecided but leaning W. High-resolution, convection-allowing models started showing meatballs of high reflectivity evolving from early convection rolling off the Front Range foothills, and fairly consistently from hour to hour. We went that way, careful not to get totally out of reach of the other area, should it go.
An early cell formed off the E end of the Cheyenne Ridge and moved E across the SW part of the Nebraska Panhandle, within reach but outside either forecast area. Even though we could see the anvil storm to our distant NNW, and it started acquiring supercellular characteristics in reflectivity and SRM displays, we stayed the course.
Even though the western area ultimately didn’t pan out, it’s a good thing we didn’t go after the first storm up north–it would have put us out of position for an amazing nighttime show we never saw coming.
Yes, the western storms never got organized. Mike Umscheid and Jay Antle joined us for a spell NW of Last Chance to shoot the breeze in the breeze, bemoaning the disorganized nature of initially promising storms that had erupted to our W. Many times I’ve seen high-based “junkus” storms in eastern Colorado, streaming mammatus and virga, their updraft regions looking like fuzzy rubbish, eventually develop into tremendous supercells. This time, they weren’t.
Deep convective towers formed in the differential-heating zone under their collective anvil edge to our S, SE and ESE, including some big ones developing where the anvil edge passed over the old outflow boundary to our distant E (near the KS/CO/NEb border confluence). They kept thickening and growing until we couldn’t stand it anymore. The models were well-past due for the Colorado meatball that wasn’t to be. The models failed. We threw in the towel on area #1 and headed E in effort to salvage area #2.
By the time we neared the familiar town of Yuma, a big, visually beautiful storm had formed from the towers still to our E, and a deep, supercellular radar echo showed up NE of Wray. As we approached the storm and Wray, we had to stop briefly for this shot looking NE, the robust updraft structure rocketing aloft through clean blue-sky surroundings.
On radar, another supercell had formed in Nebraska to this storm’s E, quickly developing a hook echo. The first one being closer, we headed through Wray to take a look. Unfortunately, the choppy terrain of the Republican River drainage (which always seemed higher than the road on its N side, where the storm was) seldom allowed us a view under the base. By the time we reached the Haigler, NEb area and could get glimpses beneath the storm, we saw a ragged wall cloud but experienced a cold N wind. Outflow! The eastern supercell had spewed a big rear-flank outflow pool that already was blasting past us, and definitely undercutting the near storm.
This mean we had to keep going even farther E, and attempt to intercept the second supercell before dark. On radar the hook looked phenomenal. Tornado warnings blanketed the storm, but in the late-afternoon light, all we saw was dark, slate-gray murk to our NE from down in the valley. While approaching Benkelman from the WSW, with occasional glances between the hills and tall cottonwoods to our NE, we finally saw the cloud base–a large, bowl-shaped lowering, and then, a smooth, tapered tube extending toward the ground! Alas, we had to keep driving to get closer, as contrast was terrible from that distance and viewing angle. This turned out to be a short-lived tornado, very photogenic from a few perspectives other than ours; but we got no pictures of it.
We didn’t see the next brief tornado NNW of MCK, probably due to buildings and other visual obstructions during our brief passage through the W side of town. Feet still on the pedal, we turned N out of MCK, finally in position to see the storm from its inflow region for a few minutes before it blasted past. N of MCK, we stopped to see that the storm clearly had cycled out of its tornadic phase, shooting outflow past us and past its once productive mesocyclone region. I was just relieved to get out of the vehicle and stand for a few minutes!
We headed back down through MCK and E of town, encountering the first really dense concentration of chasers I had seen the whole vacation. Most were well-behaved. Still, it only takes a few morons opening doors into traffic, parking halfway into the traffic lanes, and pulling out into the highway without signaling and at dangerously slow speeds, to heighten tension and create unsafe experiences for everyone. I did a lot of honking and, I must admit, played a little “finger music” in the direction of some of the thoughtless dipwads.
The storm itself, a ragged mess charging toward us and right behind us as we rolled ENE on US-34, almost became an afterthought, as we dodged needless human-caused traffic hazards. [Others had it worse. A tour driver later told me that some sadistic yokel in front of them deliberately drove 20-25 mph in a 55-mph zone for several miles, visibly laughing at and mocking them the whole time.]
I was on edge, and ready to blow this whole ordeal off. Fortunately, darkness started to set in, further motivating us to bail S, out of the way, and search for lodging and fuel. One final observational stop S of Cambridge to view the HP mess to our WNW, and we called it a night (or so we thought). Enough was enough.
Heading E through the southern Nebraska night, we hit town after town that had rolled up its sidewalks for the night, all services closed, no petrol or lodging to be found. Finally we reached Alma, tired, irritable and frustrated after a long day, needle nearly on “E”, having had nothing for dinner but snack food, the last few hours spent mostly stern-chasing or being chased by a difficult, messy, tornado-warned storm, without seeing much except for occasional dumb drivers. Regrettably, I was neither the most clued-in nor the friendliest person to be around at that time. The good news is that fortunes would change for the better very soon.
We noticed a locally run motel, of the sort we prefer against the national chains for their personal service, charm and generally lower cost, this one with only one vehicle there. Fortunately the proprietor’s wife still was awake; in fact, from elsewhere in town she saw us arrive and drove over to check us into a big room with a king bed.
As we unloaded the vehicle, lightning flashes from our old storm increased in intensity to the WNW. Radar examination confirmed that it still was a supercell, headed on an easterly path toward our near-north. A quick check of profiler and VAD winds told me the storm had latched onto the low-level jet and would persist for awhile. Even as tired as we were, the lightning-viewing and photography opportunity was irresistible.
We parked next to a plowed field off the NW edge of town as the formerly messy and ugly supercell spun into view as a dazzling, spinning wonder of electric light and swirled cloud sculpture. All our tension and exhaustion vanished effortlessly, replaced by enraptured wonderment. For a brief time, someone (we later found out it was our friend Brian Morganti) cast headlights across the field, which didn’t bother me since it illuminated the foreground in an interesting way as well.
After spending an hour or so in the presence of that gorgeous sky spectacle, we watched it fling two arcus clouds overhead, blocking view of the best structures, then turn somewhat leftward and weaken. We headed back to the motel and got ready for bed, finally satisfied with this chase day.
As I was looking over some final data for determining the next day’s target (which looked to be very near where we were!), a last-minute radar check showed another supercell had formed on the southern end of a short line of storms to our WNW. It was headed on almost an identical path as the first! Quickly glancing outside, we saw distant but frequent flashes. Could it be? Could we get another amazing light and structure show?
The clock already had turned to the date of June 20. It was after midnight, and we needed to get to sleep and get some breakfast in the morning. It was so tempting to fall face first into the pillow and ignore the call of the strobing sky. Another glance outside: the light show was closer and brighter and strobing even more frequently than the first storm had from the same indirect view. We knew what to do.
One o’clock a.m. found us next to another field on the NW side of town, camera on tripod, nighttime supercell number two whirling its way across the sky, bathed in almost continuous, flickering illumination from its own relentless lightning engine. Wow. To be gifted in this way was a blessing beyond measure. Nobody else was out there this time; we had this one all to ourselves. As the brilliant display scooted by to the NW and N, a carpet of thousands of blinking fireflies rose from a grassy part of the field.
This experience, in total, was unbelievable. I shot dozens and dozens of photos of both storms, every last one interlaced with filamentous tendrils of in-cloud, cloud-to-cloud and cloud-to-air lightning. Of these, seven have been selected at somewhat larger resolution for a special web page devoted just to this night.
We slept very well after returning to the room, finally at ease and completely contented. One more incredible chase day awaited on what already was among the most spectacular and rewarding Great Pains vacations I’ve had.
Beautiful Outflow, Day 3: Along a Familiar Trace
Filed under: Summary
Limon to Sheridan Lake CO (again!)
18 June 11
SHORT: Observed high-based, outflow-dominant supercell with “cheezenado” near Kit Carson CO and deeply textured spectacle of structure. Pretty sunset near ITR.
LONG: This was the third straight day of outstanding outflow in the American Outback. We started the day in LAA, with a stop at Bent’s Fort along the way to our target area, which remained the LIC-PUB corridor as supposed the previous night. While the Fort was fun to visit and photograph again, we slept in too long, got there later than hoped (midday), and stayed long enough to miss the initiation and early stages of a supercell near LIC.
Roaring N out of Rocky Ford, we caught up to the thrice tornado-warned storm just S of LIC (it was, fortunately, rather slow moving up to that point). Despite its fine appearance on radar reflectivity for over an hour prior, early visuals suggested nothing even close to tornadic: a high based storm with a rather small, tilted updraft and opaque to translucent core. The temperature in that RFD was 56 deg F, not exactly priming the pump for tornado action given the lofty LCL of the storm.
We took a little bit of mainly sub-severe hail, from the trailing (rear-flank) precip area while turning around to jog S and E toward Hugo. A major core-dump just N of Hugo (as seen looking NE from just W of town) sent the storm on a southeastward, outflow-surfing odyssey that seemed quite familiar. Already, the irony wasn’t lost: the storm of interest was in the same general area, also high-based and apparently outflow-dominant, and headed roughly the same direction, as the supercell the afternoon before. Indeed, we would retrace much of the previous day’s familiar path.
One difference this day was that the storm legitimately threatened to produce something tornadic on two occasions–both when my phone’s signal-bar area was stamped “No Service.” [Thanks again, AT&T with your disingenuous “97% of the population” advertising.]
We pulled off US-287 near Wild Horse and drove a few miles up a dirt road for a better view, only to see that the terrain constantly was higher between us and the storm. As we got closer, a lowering I had seen for a few minutes in the distance became visible as a persistent, smooth, bowl-shaped (and sometimes fat-cone shaped) protuberance embedded in translucent rain. It was rotating–not very fast, but noticeably. As I got out to take this wide-angle shot, the lowering’s bottom became more rounded and higher, and it went away within a minute. I was imagining what a supercell like this could do with less outflow, lower cloud base and more inflow-layer moisture.
Meanwhile the already-nice structure just kept getting more and more textured and beautiful (looking NW from near Kit Carson). The sharply defined, undular raggedness of the bottom of each cloud-base terrace gave me the impression of looking upward from beneath at a boiling liquid surface.
::::: Begin meteorological interpretation :::::
In a way, though the causative processes are much different, the convective principle is quite similar, when you consider the “liquid surface” analogy as a reverse counterpart of the CCL or LCL. In boiling water, the liqud turns to vapor. At the cloud’s LCL or CCL, the vapor condenses to droplets. Amidst a very broadly intense updraft, little bitty parcels neighboring each other are reaching their condensation pressure fast, but at slightly different elevations, giving the underside of the cloud mass such a rough, sandpaper-like appearance. The difference in condensation level from any one of the “mini-parcels” to another probably is related to a combination of slight variations of pressure, temperature and/or humidity in each one, before and during its ascent. This contrasts with the laminar (smooth) bases we often see in supercells, where the vertical pressure-gradient force compels a sheet of air to rise along a gently sloping path (along an isentrope) to a less locally-variable LCL, then ultimately to its higher LFC, where now unshackled from CINH, it really goes ballistic and rockets upward at speeds even faster than CAPE alone can support. In this specimen, LCL and LFC were either roughly the same level, or LFC was lower (free convection occurring before saturation).
::::: End meteorological interpretation :::::
Back to the chase… This stunning view (17 mm wide-angle), looking W from 6 W of Cheyenne Wells back toward Kit Carson, compelled us to stop for a spell, knowing that the forward-flank core would move overhead and force a southward turn of our own soon. Little did I know that this most unlikely-looking of high-based High Plains storms was about to produce a tornado.
See the precip-filled occlusion slot in the lower middle of the last photo? A few minutes later, as I was gawking and babbling with semi-coherent admiration at the sky-filling structure, I heard Elke yell, “I think there’s a tornado in there!”
Me: “In where? No way!”
Elke: “Right there!”
Me: “Right where?”
Elke: “In there!”
Me: “In WHERE???”
Elke: “In the rain! Behind the updraft!”
Me (fumbling with camera gear): “Come on, from that storm? There ain’t no…hmm, wait a minute. Holy $%#^, that is a funnel in there. Get on there, stupid zoom lens. Dust! I think it might be a tornado!”
As usual, she was right. At least this time, she didn’t have a road atlas with which to hit me. 🙂
It was short-lived (~3 minutes), a long, slim, very stretchy condensation tube that began to break up even as I finally got the zoom lens attached and snapped the photo. The enhanced crop shows some of the dust it had spun up from the dry fields beneath. Other observers who were closer to the cheezenado’s location (SE of Kit Carson) also pegged it on a couple of SpotterNetwork icons, as I saw later once regaining data coverage. It was a flimsy excuse for one, but still, WFO GLD’s first tornado of the season. [The reports on the day’s rough log actually were of that one event, seen/reported from different places.]
As we dropped S out of the Wells, the brief spin-up soon became almost a forgotten sidebar in the face of one of the most fantastic and bizarre visual appearances I’ve seen from any storm. At that point, other cells were merging into its back side, with an initially separate storm base visible in the more distant W.
The supercell quickly was evolving into a small forward-propagating MCS, ralphing even more outflow. The resultant, bigger storm cluster formed a pretty, tiered shelf on its E edge (looking NE). Back to the WNW of us, an outflow-undercut but visibly rotating convective column briefly formed and poked into the ambient cloud base, adding more morphological weirdness to the whole event. The earlier “rear” storm, visible in the last shot, also was growing bigger, getting closer and becoming outflow-driven.
Pulling into the same Sheridan Lake petrol station where we had been the day before, I fueled up and spoke with some familiar faces behind the counter. “We’re back, and we brought another storm with us!”
I also chatted with Chris Weiss of TTU, whose Sticknet teams I had seen deploying their wares along US-385 as part of some sort of outflow-measuring experiment. [They had arrived at the storm right after the cheezenado and didn’t know about it.] That bunch should have acquired a great dataset; for the gust front soon barged through town unabated and well ahead of the main core, which itself turned left and barely missed to our E.
A few minutes later, a very concentrated and suspicious-looking, but non-rotating, dust bomb rose to the SE. Plow wind! The dust plume fanned out, advected away and eventually dispersed, as we turned back N for the 63-mile drive to ITR and a favorite motel there.
Along the way, several elevated and very high-based storms formed atop the cold pool from the earlier complex, including this one just S of ITR. South of town, we enjoyed a splendid sunset sky while parked in between wet plowed fields, and while talking to Rich T on the phone. He had seen his first tornado of the year that day–400 miles to our SE, along the OK/KS line W of BVO. We were glad for that too, as his chase fortunes this year had been awful so far.
After three days of beautiful outflow, we were ready for some meaty supercell action as portended by richer moisture and stronger shear forecast for the next day.