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.
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Our PING trail for this day.
Pawnee Grassland Supercell and Sterling Sunset
Filed under: Summary
Cheyenne WY to Sterling CO
15 Jun 13
SHORT: Chronically photogenic storm from CYS to Sterling.
LONG:
We began the day in Ft. Morgan with increasing (but still marginal) low-level moisture feeding two forecast plays:
- The dependable Cheyenne Ridge/Laramie Range region, which seldom fails to pop a storm under upslope flow and substantial surface heating, and
- Palmer Ridge/Front Range area farther S, similarly dependable but under weaker flow aloft.
My privately posted chase forecast discussion read, in part…
“This pattern strongly resembles several that have fired grand supercells off the LAR mtns NW CYS — some with spectacular tubes — though moisture today is a little less than I’d like to see it for tornadic action. Postfrontal winds should turn around after 18Z and go upslope into that area. If a storm can fire over there, it could proceed ESE through the extreme SE part of WY and eventually in an oblique path across the NE CO border…”
That was the scenario we selected; and fortunately, that’s exactly how it worked out. Such success doesn’t happen as often as I’d like, so we should celebrate when it does. On this day, we celebrated with some splendid stormscapes and one of the best Great Plains photography days of the year.
First, however, we ate a great buffet lunch at a highly-reviewed place in eastern Ft. Morgan, away from all the main highways: the Country Steakout. Try them next time you’re in the area, especially if you want to get really full, before a chase. We then trekked through the Pawnee National Grassland on the way to the CYS initiation target. [We would return through this amazing area later in step with the supercell.] Along the way, we found an abandoned farmhouse that showed us decent photo opportunities even at midday (samples: outer wall texture, another outer wall scene, light and shadow through a window and on the floor, more exterior boards).
After that, a lone Cb arose off the WNW horizon, which satellite imagery confirmed was firing off the southern part of the Laramie Range, just as hoped and predicted. We headed through CYS, passing Mike U and a few other chasers along WY-211 (Horse Creek Rd) to find an excellent vantage for the approaching storm, which offered a large and textured but ragged and elongated updraft base.
Peeling itself off the highest terrain and heading ESE, the storm kept that elongated-updraft look after crossing the Colorado border near Hereford. Although this storm flirted with excessive downdraft production and outflow-dominance on several occasions, it was able to maintain just enough proximal inflow to keep from gusting out–remaining photogenic all the while. A view to the E, from the same spot as the last shot, showed multiple, parallel, cumuliform inflow bands feeding into the high base. What an interesting and beautiful process to behold!
Road voids over the buttes and mesas (here spotlit with sunlight against a dark storm background) kept us somewhat distant from the storm at times, and/or relegated to its SW side, but that was obviously not a problem from a photographic standpoint. In fact, we stayed on the western fringes of both the storm’s rear-flank core area and the Cedar Creek wind farm to take advantages of (and marvel at) scenes like this and like this.
Back roads delivered us healthy and well to CO-71, whereupon we headed S to CO-14, stopping along the way to view the gorgeous towers to our NE over the shortgrass prairie. Eastward we moved on 14 to get back near the SE-moving, high-based supercell, which seemed to be accelerating. Daylight fading, we decided to stay in good light and on the storm’s back side as it approached Sterling, and let the rear-flank gust front and its wondrous collection of tinted cloud material pass over the green wheat fields.
Sunset time was a dazzling experience, with elevated storms that were growing to the W helping to cast differential light, shadow and hue across the convective sky to our immediate SE. I had to slap on a multi-stop graduated neutral density filter to offset some of the dynamic range (old-fashioned, I know…but it worked out well). At times, the colors were out of this world…seldom have we witnessed such a variety of light and texture in such a small part of a convective sky! The experience was amazing–parked on a remote, dirt back road with nothing but us, the sky, the cool breeze, and some singing meadowlarks for company. This is why we travel to the High Plains every year.
The convection to the W grew larger and started putting on a fairly furious electrical show after dark, but we had to forgo lightning photography to get Elke some suddenly-needed medicine in Sterling. That wasn’t available, so we headed promptly down I-76 to to the outskirts of DEN for the night, enjoying the flickering light show in our side windows and rear-view mirror while hoping she would be healthy enough to chase the following few days (great news…she was, and we had a fantastic chase in the Nebraska Sandhills the next day!).
Wyoming to North Dakota via a Nebraska/South Dakota Dryline
Filed under: Summary
Cheyenne WY to Bowman ND
8 Jun 12
SHORT: Observed dryline towers, sometimes with smoke, near the NE-SD-WY state-line junction. Nice sunset over the SW corner of ND.
LONG:
Three main target areas presented themselves to us as we pulled out of CYS on a sunny morning:
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1. The closest but probably lamest: a high-based, deeply-mixed prospect for short-lvied, late-afternoon convection along the dryline, near the S rim of the Black Hills;
2. A middle play along the NW rim of a narrow plume of relatively righ boundary-layer moisture, collcated witha confluence belt, in the SE MT/NW SD/SW ND area. This had been apparent for a few days–distant but reachable, given the likelihood of a stout cap holding off storm potential until late afternoon.
3. More certain risk for a photogenic supercell or two in central MT, more removed from the richer moisture but in favorable deep-layer wind profiles. his was barely reachable with some long, hard driving and only brief stops, followed by a short night’s sleep and another day of long, hard driving to get all the way over to NE ND. That’s hardly the recipe to be able to stop occasionally and get out to appreciate the Great Plains!
Given the low likelihood of tremendous tornado action in the middle of Montana, we nixed option 3 early and decided to make a conditional play on the first two. We would head NNE to the CDR-CUT area for the dryline, then if it looked unpromising by around 21Z, be ready to zoom up through RAP toward 2WX where at least one high-resolution model (HRRRRRRRRRRRRRRRR) forecast a distinct supercell to develop.
Lunch in Lusk was good–Deacon’s Restaurant is one we can recommend! Appetites satiated, we took a back road–sometimes paved, sometimes not–to Van Tassell, stopping here and there to appreciate geologic formations as well as photograph abandoned structures from up close, in the middle and back a little.
The whole way from Torrington to Van Tassel, we kept an eye on the high-based cumuli accumulating in a persistent area of lift that passed overhead, then shifted E to the Nebraska border in step with the mixing-driven movement of the dryline. This photograph depicts the deepening convection from near Van Tassell WY, gazing ESE toward the dryline. A horizontally narrow but vertically thick ribbon of smoke from the Cow Camp fire in Wyoming (the inferno whose pyro-convection started the Wheatland supercell the day before) also was streaming steadily northeastward toward us, several thousand feet above ground level.
Van Tassell in the review mirror, we headed through Fort Robinson on the Nebraska side, passed through the dryline near Harrison, gathered some rocks on the escarpment E of Harrison, stopped briefly for supplies in Chadron, then headed NW toward the South Dakota border and one skiny but persistently deep tower. When we got to it, the tower obviously was suffering from dry entrainment, but presented a peculiar picture of light and shadow, as seen from underneath the ribbon of smoke and very near the state line.
Unconvinced of its future, we proceeded N beneath the ENE-moving tower’s base, encountering a few raindrops. A small Cb actually did develop briefly as we passed just to its N, and weak reflectivity appeared with it as seen from RAP radar. Still, given the degree of entrainment, and the presence of a few more hours of daylight, we headed up past RAP, Spearfish and Belle Fourche toward 2WX. We were worried that a traffic jam, in an I-90 roadwork zone NW of RAP, would make us miss any storms that formed to our NNW; that turned out to be a moot concern.
We waited for a spell in 2WX, calling Bowman to reserve a room, the threw in the towel on any model-phantom storm formation nearby and headed N to our lodging. Along the way, we stopped on a hilltop just N of the Dakota divider for a photogenic Northern Plains sunset. OF Crowther’s supercell is the Montana storm silhouetted on the horizon, about 190 miles away. Ain’t it amazing to be able to see that far?
Even though the chase day didn’t amount to a whole lot convectively, we enjoyed each other’s company, had a few unusual and welcomed photo opportunities, and positioned ourselves to get a good night’s sleep before the diagonal crossing of North Dakota the following day. In Bowman, we even saw a long, bright, overhead flyover of the International Space Station before turning in.