Afternoon Towers, Twilight Flashes
Seminole & Tecunseh, OK
15 Apr 13
SHORT: Struggling but occasionally photogenic convection near Seminole OK followed by lightning observation on back side of twilight storm complex.
LONG: During the day, a cold front had hung up along a weak frontal-wave low about 40 miles to our SE, closer than previously expected. While driving home from a dental appointment, which followed a day shift at work, two main things were on my mind–the Boston bombing, about which I learned at the dentist, and the towers going up on that boundary, visible to the SE.
Storms were more palatable to contemplate than the other grim issues of the day, so I headed home and picked up Elke for a short trek E. The better environment for photogenic, diurnal supercells was in north-central TX, NW of the Metroplex; but that was too far to reach before dark. We were hoping the cap could break closer to us, along an increasingly well-defined inflection point that lay nearly stationary over the area between Wanette and Konawa. That point also corresponded to the intersection of the frontal zone with a confluence line extending behind it to the NNE, and was persistently focusing the deepest (albeit still cap-dominated) buildups.
This part of Oklahoma is hilly and moderately forested, so high spots with good visibility are rather scant. During the couple hours or so before sunset, we waited at two places along US-377 S of Seminole–one right on the boundary, and another just to its N with better visibility. From the first, we saw one Cb erupt on the inflection point, briefly acquire strong radar reflectivity, then tear off to the NE, along the confluence line but also on the cold side of the boundary.
From the second stop, closer to Seminole, we photographed intervening towers with crepuscular rays, as a newer storm developed to the SW. The second Cb approached, skinny and pockmarked with holes, but beautiful to behold nonetheless. That likewise withered, so we headed into Seminole to grab some fast-food dinner and await further developments.
After supper, we saw a multicellular cluster forming back on the frontal wave and inflection to the SSW, and decided to get on the NW side of it for sunset color. Several cells emerged from that mess, including:
1. a sunset-illuminated left mover W of Tecumseh,
2. a right-moving supercell that we actually blew off because of its positioning on the dark side of the cluster, and
3. another left-mover to our E that was buzzing with a lot of in-cloud lightning discharges. The sky actually was darker than the photo makes it seem, due to the length of the exposures. Still, I wanted to strike that fine balance between bringing out the convective structures while not exposing for too long and blurring cloud features on a fairly quickly moving storm. How quickly?
Since then I’ve created a time lapse of the tripodded lightning shots I was attempting, so that you can gain some appreciation of the beauty of the third cell as it cruised fairly rapidly across the twilight skies to our SE. Please enjoy it. The time lapse spans six minutes, so you can see the fairly fast translation of the storm. Dial the speed meter up to the max level for full effect.
It was a mild, beautiful evening to watch the dynamic sky!
Over the Belle Fourche River
Elm Springs SD
15 Jun 12
SHORT: Another rewarding day considering low expectations. High-based but high-contrast and scenic storms over scenic High Plains of western SD.
LONG:
The prior day, Matt Crowther and we had enjoyed a nonconvective hiking and driving adventure at Devils Tower, staying in Hulett, WY. Highly recommended: the airport/golf-course restaurant at Hulett, which is on a plateau overlooking the town and Devils Tower…great steaks and (according to Matt and Elke anyway) good beer and wine too. On this day, Elke and I did laundry in Belle Fourche while Matt dealt with some car maintenance, then we met at a high spot overlooking Belle Fourche Reservoir to watch for convective initiation.
Moisture was progged to be modest and analyzed to be downright meager. A series of MCSs over the southern High Plains during the previous few days had precluded ample return of rich boundary-layer moisture to these regions, though low-level storm-relative inflow and marginal shear were likely just to the E of a north-south trough near the SD-WY border. Our supercellular expectations duly tempered, we were content to see any sort of photogenic convection on this day, over such a beautiful landscape as the western SD plains.
While manning our convective sentry near the lake, deep towers began to develop over and immediately NE of an apparent source of lift located very near the northeast fringe of the Black Hills. The convergence zone associated with the trough appeared to shift E somewhat and intersect an area where heating of higher terrain was aiding in a sort of chimney effect for turrets tilting downshear. We zigzagged E and S past Nisland and Vale, stopping a couple times along the way to photograph the resulting young Cb that erupted into the deep blue Dakota sky–here with an abandoned shack and Bear Butte in the foreground to our SE, and here a couple minutes later with “just” the wide-open short-grass prairie. We headed S toward Bear Butte, stopping at an abandoned, antique pickup that Elke and I noticed ten years prior. I long had wanted to photograph that truck with an interesting sky in the background, and this was the welcomed result!
Navigating around Bear Butte, we took a winding, generally ENE course along SD-34 and across the Belle Fourche river, into a part of the state nearly devoid of paved road options and scant for river crossings of any roads. Our original storm attempt fizzled away as we drove beneath it near Volunteer, but a new storm developed rapidly in the upshear convective plume. That one, to our SW as seen from 9 NE Hereford, sported a much more robust updraft base and seemed to enjoy a nutritious blend of greater buoyancy and less entrainment (great taste, less filling?).
The storm was turning somewhat rightward with respect to the road, casting the increasingly precip-laden forward flank over the highway. Lots of other deep towers were erupting in all directions as well, including beneath the anvil of the main storm. This all forced a difficult intercept decision:
1. Continue ENE out of all the precip, wait potentially 1.5-2 hours for whatever was left of the storm (could be very messy!) to cross the Cheyenne River and get within good viewing range of a maze of mostly dirt roads on the other side, or
2. Cut S out of Enning toward Elm Springs on a dirt/gravel road whose maps advertised a crossing of the Belle Fourche River, figuring the road had to be at least passable if it connected two towns.
Being in South Dakota, we were wary of any option involving back roads, which quite often are in utterly wretched condition there. Nonetheless, we headed S, figuring the Elm Springs route would afford a decent one-pass opportunity to watch the storm approach us, then cross. It did.
Few other apparent chase vehicles appeared, so we had a reasonably peaceful viewing stops north of Elm Springs, including this pleasant westward view across golden wheat fields. As the storm drew closer, the arrangement of precip cascades in its forward-flank region offered some peculiar visuals.
Not desiring to be in the core, while on an unfamiliar dirt road, we continued S across the now-familiar Belle Fourche River to a spot just NW of Elm Springs, and let it cross to our N. At this time, the leading-edge updraft assumed a somewhat circular shape. A small, very weakly rotating convectively bubbly wall cloud formed, above a ragged scud tail related to the updraft’s inhalation of forward-flank outflow.
Within minutes, a separate area of outflow from an expanding rear-flank core demolished the whole regime. The entire storm then surged east, but not before offering a short yet spectacular CG show (photos looking NNW and then looking N), from what was left of the forward-flank area.
After the storm crossed into the road void of the Cheyenne River valley, it merged with other cells, grew upscale into a mess, and lost definition, leaving us in the unusual situation of “chase over” with plenty of daylight left. The next day would be a down day weatherwise anyway, with palatable supercell potential in better moisture slated for eastern SD day-3. As such, we cruised into Wall for lodging and dinner, anticipating the next day of photography and exploration in the uniquely beautiful Badlands National Park.
Storm Observing Drama in Four Acts
Southeastern WY near Cheyenne
7 Jun 12
This storm day was striking in that it unfolded as a four-act drama–each one quite distinctive, essentially a quartet of distinct chases in one day. Seldom have I experienced so much logistical and emotional ups-and-downs in such a small area in one trip! We went from intense frustration to elation and satisfaction, with one or two minor dollops of danger thrown into the storm-intercept recipe for good measure.
Act I: Early Poor Decisions and Frustration
Elke and I targeted southeastern Wyoming for the potential of a supercell or two forming in a region of decent upslope lift . As we headed W from Pine Bluffs WY toward CYS, a storm formed in the Laramie Range and stem-wound itself into an intense supercell while still in high, rugged terrain. It turns out that storm formed as a pyro-convective plume off the Cow Camp wildfire, and became tornadic while still sucking smoke up in the mountains.
[NOTE: The write-up in that link does contain one major error--tornadoes cannot "skip". By definition, if it's "not on the ground the entire time", it's not a tornado the entire time! As such, each segment had to be a different tornado.]
We arrived in CYS intending to head N on I-25 and intercept that supercell, or whatever was left of it, somewhere not far N of Chugwater. Then a new storm exploded into the Wyoming sky just to our NE. A bit of indecision followed, before we made the fateful choice to take a look at the younger cell. The storm farther away looked better on radar, but the new one was right there! How do you blow off a storm blowing up practically in your lap? We should have. This move ultimately cost us any shot at a decent view of the Wheatland/Chugwater tornado(es).
We headed the short distance back E toward Burns and then N, finding that the newer storm was shriveling, while the fire-generated, tornadic supercell to the NW still was going (and still had a likely tornado, given its radar signature). I was not happy. Still, zooming up US-83 toward the west turn to Chugwater, we thought we were in great position to intercept the big supercell while still tornadic. Indeed, given the official timeline for the event and our terrain-truncated vantages, Elke and I are now sure we caught some glimpses of a cylindrical, mostly rain-wrapped tornado just over the high ridge line in the distant WNW, while driving.
I turned the vehicle W on WY-314, seemingly in ideal position to catch the end of the tornadic stage, and then about 8 miles along…a one-lane road, pilot-car closure with no pilot car! This was about when it seemed that our chase day just wasn’t meant to be. One lone lady in an orange vest was standing there with a flag, stopping all westbound traffic–most unfortunately, in about the lowest bottomlands where neither she or we could see diddly-squat.
Diddly-squat, in this case, consisted of a tornadic supercell and its approaching forward flank. We told her about the storm, its likelihood of lightning, skull-cracking hail and flash flooding…but she seemed oblivious, and totally dependent on a radio dispatcher who was (quite irresponsibly) giving her no information at all about the storm. She finally assured me she would crawl into a nearby tinhorn if it “got bad”–which wasn’t much assurance with regards to her safety. Other than that culvert, there was nothing out there in which to take shelter! Alas, that was the best I could do to convince her she was in potential danger.
Thus thwarted, we turned around and headed E and uphill several miles, finally getting a view of the storm’s base less then 7 minutes after the tornado is on record as dissipating. [Without the closure, we easily would have gotten on the plateau E of Chugwater in plenty of time to see the last moments of the tornado, across a flat and unobstructed landscape.] The supercell appeared to be getting more disorganized, with newer development to the SW…so we headed back E to US-83 then SSW toward CYS. That turned out to be the first good maneuver we made all day!
Act II: Storm Structure Bliss
As we approached the newer storm, more and more chase vehicles appeared beside and on the road–the only decent road around for miles and miles. It was easy to see why–the storm erupted SE of the first one, right along the way for a lot of observers from Colorado and elsewhere who were zooming up toward the Wheatland storm when it fell apart. By contrast, we came around it from the NE and E, found a vantage to let it move toward us, and marveled at how the structure was getting better and better as it drew closer and closer.
The main updraft base sported a persistent, broad wall cloud with occasionally fast rising motion on the downshear (core-facing) side, but never anything I would call rapid or tornado-like rotation. Meanwhile, the storm-scale formation assumed a sweeping, curvaceous stack across several layers in the vertical.
With a dearth of road options in the general direction of storm motion (SE), we kept letting it come our way until the wide-angle lens needed switching from 24 mm to 17 mm. At one point, I recall telling Elke that I wished I could teleport Al Moller here–he would go absolutely euphoric over seeing this storm in person!
The old wall cloud and mesocyclone area began to assume a more shelf-like appearance as they passed our location, and the entire storm looked a little more disorganized. The only roads back ahead of the supercell led through the core; so we had to retreat away from it in order to reposition.
Act III: Outflow and Hail Machine
We went SW down US-85 and I-25, around CYS, then back E again, then S of I-80 between Burns and Carpenter, for an encore look at the increasingly messy storm. Another supercell also had developed to its east, its updraft base cloaked by precip for the time being; it was menacing Pine Bluffs.
We pulled onto a side road to observe the onrushing maelstrom, greeted by a big, very friendly and rambunctious chocolate Lab, muddy-legged but healthy and well-fed. He probably belonged to a farmstead about half a mile away. The pooch took a running, leaping jaunt through my vehicle and out the other side before we shut the doors! If you ever are traveling with me and happen upon dog-paw prints, that is the reason. He hung around nearby for a spell until the storm spooked him back toward home.
Since we had left it NE of CYS, the western supercell had become more elongated, with a somewhat surfboard-shaped base. Since it was riding its own outflow, this was appropriate! As that storm approached us from the northwest, the Pine Bluffs supercell weakened, shed some precip, and became higher-based. It also trailed a beautiful rear-flank arc cloud that curved right back into the updraft region of our storm (wide-angle view looking E).
Dropping S somewhat to get late-day light under the rear-flank gust front region, we had a decision to make: stay apace and just ahead of the increasingly messy storm and its neighbors southward into Colorado, thereby missing an opportunity for sunset light on the back (NW) side, or go for the colorful view. We usually choose the latter in such situations, and did here, with ease. What wasn’t easy was deciding how. The updraft and main core area each appeared to be weakening some, so one way was to head straight N through the precip and back to I-80. The other was to go W on an unfamiliar road zigzagging along the crest of the Cheyenne Ridge, and hope for a good view before reaching Cheyenne itself.
We chose to attempt the former, and if the hail started getting big, backtrack and do the latter. Just a mile or so into the precip core, we hit a very sudden wall of severe hail that started beating the hell out of the vehicle, somehow sparing the windshield. Spiked bombs of ice bounced high off the road, splashed in surrounding mud, and created sickening booms as they slammed into the metal skin above. So much for the “weakening” core!
Even the quickest of Bo Duke-style turnarounds on an empty road, in a vehicle that is not quite as nimble as the General Lee, couldn’t spare us from its first easily noticeable hail dents. I blasted back S and got out of there before the beatings became worse, then headed W out of Carpenter on Chalk Bluffs Road. We’re so glad too, and not just to avoid demolishing the outside of our ride…
Act IV: Amazing Stormy Skies on the Cheyenne Ridge
Eager to escape the ice monster, we bolted 12 miles W and NW on the road from Carpenter to Cheyenne, the stopped at a very nice 360-degree vantage for one last look back SE at what had tried to turn my finely tuned storm-intercept machine into Swiss cheese. The hail core is at left in the last shot. Yes, it was still a supercell…so what, and good riddance! It was almost time for sunset magic.
But wait…what happened to the sunlight that had been behind the storm we just got behind? All manner of cloud material had developed and masked much of the sky to the NW and W, and a small, left-moving storm was moving from my SW toward the NNE…dragging its precip core toward us. Furthermore, it was rather stinking cold up there on the High Plains ridge–low-50s temps and windy from the supercell’s torrent of outflow!
Just as I despaired over this seeming state of misfortune, two glorious happenings made our day. A mammatus field to our NE, its sunbathing not blocked by clouds, came aglow brilliantly for a few minutes, while casting reflected, bronze-toned front-light onto the landscape to our W.
Meanwhile, the left-mover to our WSW drew closer, strengthened, and unloaded a protracted, stupendous salvo of high-based, cloud-to-ground lightning strikes for many minutes more! Set amidst the warm chromatic ambiance the setting sun, the scene soothed the soul, even as sharp thunderclaps boomed across the miles of chilly High Plains air. Electrical jabs blasted to the ground, truncated up in the air and jolted forth at closer approaches, until we finally had to abandon our post
for safety’s sake.
Heading westward between Campstool and Altvan, through the edge of the left-mover’s translucent core and toward CYS, we encountered a second barrage of hail. Most mercifully were no bigger than dimes, but it was very hard and noisy. Leaving that barrage, our minds were firmly fixated on securing lodging and a hot meal, when a window of amazing color and light briefly opened in the southwestern sky, as if magically. The haunting vista seemed as if we were peering out from within a cave of darkness at an extraterrestrial world light-years removed.
Epilogue: Dinnertime Hailstorm
After getting a motel, we found a Perkins near downtown CYS that still was open, and headed in for a supper that was late, but most welcomed, after a day of wildly fluctuating fortunes out on the road. As we did so, I saw lightning flashes outside, then flipped on the phone radar to see that a high-VIL core was almost upon is from yet another elevated left-mover. The resulting heavy pounding of small hail reverberated through the building, as a small flash flood washed down the low spots. Drifts of the stuff washed through the parking lot and against the wheels of my vehicle–all for our entertainment.
Our third encounter with a hail core was the most fitting way to end the storm day! Everything we had seen since leaving the destructive supercell supported the ideal that long after the main supercellular action concludes, the storm-observing day can proceed with wondrous and spectacular results. For all the lackluster results of the previous day’s storms, this one made up in multiples. Moreover, as of July 28th (this post date), we saw more rain in half an hour in Cheyenne than in Norman during the nearly two months since.