Serpentine Belts, Coal Dust and Purple Lightning

August 31, 2007 by · Comments Off on Serpentine Belts, Coal Dust and Purple Lightning
Filed under: Summary 

NE Wyoming

16 Jun 2007

SHORT: Minor midday car trouble in Bighorns, could have been much worse. Fixed. Outflow-dominant, sometimes photogenic storms intercepted in GCC and Wright areas. Top-5 favorite personal daytime lightning shot taken.


Seldom have Elke and I had a more unpredictable and adventuresome nontornadic chase day, complete with enough twists, turns, minor intrigue, delights, frustrations and unexpected weirdness that I might have thought the ghost of Rod Serling was along for the ride.

Enticed by the potential for discrete supercells somewhere in northeast WY or southeast MT on the 16th, we drove up the day before from Denver, timing the trip for any low-probability frontal Cb development between Casper and Buffalo WY. Deprived of desired convective eruption, we grabbed a room and had a nice dinner in Buffalo, then headed up part of the Cloud Peak Skyway to see part of a range we hadn’t experienced before — the Bighorns. We were amazed at the profusion of wildflowers that cloudy evening, and vowed to criss-cross the range the following morning before resuming storm intercept activities.

The morning of the 16th, we had a great time driving, shooting photos, hiking, eagle-watching and fishing in the mountains. That is, until the car uncharacteristically overheated while climbing up-canyon from Tensleep. I pushed the old sedan too hard uphill, I guess, and it pushed back. Fortunately I noticed the temperature gauge climbing visibly and pulled over to let things cool down, hopefully before the thermostat could get damaged. This would, at a minimum, delay the chase day a bit once we reached the other side. Bummer.

As I passed the cooling time exploring under the hood, I noticed that my serpentine belt had a jagged, two-inch crack in the middle with light shining through. Big, big bummer. The belt was fine several days before, but since had entrained a pebble into its grooves which, in turn, caused a stress fray to work through to the flat, visible side. And I had forgotten to pack a spare belt before the trip…%$&#@^*! With the motor finally cooled, the thermostat still uncertain (turns out it was fine), and the all-everything belt splitting apart, we limped over Powder River Pass and through the mountains deeply burdened with automotive uncertainty. That inch-wide strip of fibrous rubber could shred any second, rendering the car useless on the spot. Up at 8,000 feet, it was approaching mid-afternoon on a Saturday, and we just hoped to get down to Buffalo and find a garage still open before the belt would rip itself to ribbons. I had all but written the chase day off. The next day was Sunday, which meant that with or without needing a AAA tow along the way, we could be stuck in Buffalo with no car for at least two days until minor but critical repairs could be done.

Stopping regularly to check the belt, cool the engine (just in case, though no more thermal spikes occurred) and do some fortuitous wildflower photography (why not?), we noticed anvils from Cb’s developing beyond the crest of the range, probably in the northern part of Bighorn Basin. Large scale ascent and destabilization aloft indeed was spreading over the area, and storm already were firing even back in the dry air. “Hell of a lot of good that will do us while stuck in town,” I thought.

Headed downhill toward Buffalo, I spotted stratus rolling in to Clear Creek Canyon from the east. This signaled upslope flow, as forecast. In turn, it signaled a pronounced easterly surface component on the adjacent plains, moist advection, and with the upper trough approaching, strong turning with height and increasing deep-layer shear. Normally I’m not a pessimist by nature, but I was imagining the spectacular supercell I wouldn’t see, except as great vaporous mountains of sunlit towers heaving skyward somewhere off to the distant NE, E or SE.

Somehow we not only made it into Buffalo, but found a gas station with a garage still open. The fuzzy-faced 18-22 year old mechanic on duty didn’t know if he either had the right part (he looked…he had one left) and could replace the belt (he did, in less than five minutes). There even was an auto parts store a block away where I could buy a spare. Best of all, this kid charged only five bucks more for parts and labor than I paid for the spare belt. The chase day was saved too; storms hadn’t fired yet either (except way north in northern MT, which was out of reach in any event). We couldn’t believe this good fortune. As for the old belt, I’m making fine use of it as a tree holder right now, tied to a pair of stakes in my yard. If you’re in Norman, stop by and I’ll show you that crack, which somehow never expanded.

It had been a day full of adventure, and the chase hadn’t even begun.

Before departing that morning, I had let the desk clerk at the Super 8 know we would be back after lunchtime to “check travel weather” on their hallway computer, so there we returned. An already long-lived supercell was grinding across north-central MT, just beginning to carve its amazing hail swath in a rampage of ice bombs that would last for five more hours. Another young storm, which would turn into an apparent LP (were any chasers on that?) was cranking up NW of BIL — a storm that would move across a decent road network N of town.

Anvil material from the high-based junkus in the Bighorns was spreading overhead, with reflectivities increasing and thunder audible. We still were N of the stationary front, so I decided to head E toward GCC and hold out for later development or evolution of something coherent as the Bighorns convection hit the Plains moist layer. Along the way, we took note of a robust young storm with an overshoot NE of BIL and visible about 75 miles NNE of us. If nothing else blew up by the time we got to GCC, we could turn N toward Broadus and let it amble across the road void toward us. Alas, the promising young storm choked and died almost as fast as it went up. As some of the high-based garbage moved off the mountains, it developed a shallow but rotating wall cloud, which went away fast but which I took as a good omen.

My oh my, had the sky ever changed (looking W) by the time we got to GCC and found a viewing vantage on the W side of town! The high based crap had evolved into a line of intensifying storms with a beautiful, tiered-shelf appearance (looking NW as it approached), and apparently some embedded mesocirculations that prompted a tornado warning or two. We moved several miles E of town, intending to take some parting shots of the outflow-dominant but photogenic mess (looking NNW and looking WSW) before evacuating S. This outflow later would contribute to the development of additional storms on the N side of the Black Hills, including the surprisingly tornadic squall-line storm along I-90.

The outflow hit, and before we could reach our south exit out of GCC, we were reduced to zero visibility in…jet-black coal dust! The outflow launched a dense streamer of powdered fossil fuel out of a pit N of the road, and we had the lousy timing of being engulfed in it! It was amazing nobody wrecked along that interstate. For a hundred yards or so, we knew what it must look like to a bug stuck inside a laser-jet printer cartridge. To add to the list of needed car maintenance, I would have to change an air filter clogged with frickin’ coal dust. Such a scenario wasn’t what I had in mind at the start of this — or any — chase day!

South out of GCC, we targeted a storm that was already TOR-warned along I-25 in southern Johnson County, moving in the general direction of Wright. I had forgotten that the terrain is almost continually higher W of WY-59, and it was most frustrating to drive 37 miles in 30 minutes for only fleeting, distant, truncated views like this one to the SW. By the time we got to Wright, three things were apparent:

1. Rotating bases would appear (as in the lowered area to the far right here, and to the near right in this shot) but would get undercut fast by all the nearby outflow,
2. The whole messy convective package was going to haul E quickly across the Thunder Basin National Grassland toward the western Black Hills, and
3. We were getting hungry and thinking about those delicious fajitas at the Fountain Inn’s Mexican restaurant.

We stopped briefly to watch the oncoming storms at a Park-n-Ride pull-off near Clareton, at WY-450 and WY-116. “Wait a cotton-pickin’ minute here…what the hell’s a Park-n-Ride doing way out in this remote, windswept corner of the northern Great Plains?”

Turns out that the coal miners commute there from Wright, Upton or Newcastle, then buses pick them up to take them to their work areas around Black Thunder (largest coal mine in the USA).

As the bases began moving overhead, occasional filaments of lightning crawled through the foregoing midlevel cloud deck with a peculiar and beautiful purplish hue, sometimes capped off by a CG in some random location in the NW, W or SW. This wasn’t getting any safer, considering I was one of the tallest objects for miles around, even while crouching low. After one last click of the shutter, in wishful effort to capture one of those pastel colored flashes, it would be time to skedaddle. That last try turned out to be one of my all-time favorites: a ghostly, lavender-toned ribbon coursing back and forth, alternating outside and just inside the bottom of the clouds, soon followed by an unseen CG off to the right (N).

I was tickled to snag one of these in-cloud strokes, but would have remembered them fondly even if I hadn’t. As I hope the image conveys, the sky scene as a whole was uniquely Great Plains in its stark, textured beauty, and set a fine table for the electrical discharges that would be dished up.

Oh yeah, food…we wanted to get to Newcastle before that restaurant closed, so we high-tailed it E, gust front nipping at our rear bumper and overtaking us at a stoplight in town. Dinner was very good, and the long, strange day finally would end with contentedly full stomachs and lots of moments upon which to reflect.

[If you’re interested, a small set of images from our evening and morning in the mountains is located in our digital trip galleries.]

Salvaging Fascination from the Convective Junkyard

August 7, 2007 by · Comments Off on Salvaging Fascination from the Convective Junkyard
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SW Nebraska and NE Colorado

12 Jun 2007

Elke and I began intercept mode while eating lunch and making the NOWcast via free wi-fi, in Ogallala’s Country Kitchen. The line of heavy rain producing storms intercepted us with thunderous booms — and that was just from the number and size of raindrops. There was lightning too. Several curious travelers came over to ask us about the weather where they were headed, which was fine. We were glad to help. At least they didn’t ask us if we were storm chasers, with the usual 35-odd list of the same tired old questions.

We escaped the flash flood situation by heading E on I-80 through the east edge of the waterfall. It became apparent that the messy, linear convective mode was going to dominate the area of best moisture and low level shear, in central NE. So we headed S just ahead of the line, hoping to grab a few rotating updrafts from the showers and isolated thunderstorms forming in the free warm sector, One small, ragged, slowly rotating base SW of Sutherland got undercut quickly by a combination of its own outflow and that of another storm just to its SE that sported a photogenic rain foot.

We threw in the towel on this regime in MCK, after letting a kidney-bean shaped left mover pass NWward over us. This storm had slow but pronounced anticyclonic shear in its main updraft base, which was on its NW flank. Farther S, drier air and higher dew point depressions ruled the boundary layer, and attempts at development either were linear or, if discrete, weak and transient.

The only hope left for the day for photogenic skies was if the bow echo developing ENE of COS still had some of its vim and vigor by the time we could intercept. This was the same convective system intercepted by MesoMikeU, but farther N and a little later, owing to our dalliance with the early activity in Nebraska. Shelf structure was gone by the time we caught it, NE of LIC near Joes CO, but it still was worth observation and photography. Deep, mysterious, slate-blue darkness loomed, sandwiched in between ghostly gray scud streets overhead and the golden hues of ripening wheat, punctated by a windmill, for a threatening scene of Great Plains grandeur (zoom a few minutes later).

The anvil briefly was visible through the intervening cold scud, before we plunged on through en route to Denver. Heavy rain and very little wind greeted us; indeed, while the countryside spoke “Great Plains,” the precipitation rate screamed “Mobile Bay.” After years of drought, through which came most of my experience on the Colorado plains, a most welcome unfamiliarity greeted us in the form of countless miles of rain across a verdant grassland, soaked not only by this event but many others datign back to some heavy wintertime snows.

Sandhills Supercellular Struggles and Splendor

August 6, 2007 by · Comments Off on Sandhills Supercellular Struggles and Splendor
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Hyannis to Ogallala NE, 11 Jun 2007

A long swath of western South Dakota and Nebraska — even down into NE Colorado, looked like it carried the potential for supercells on this afternoon, and I was wandering up and down the dryline with my preferred target area all morning. Ultimately I had to make a basic N-S decision, and I chose S, despite the prospect that storms could form and/or track into the western Sandhills. This was because of richer moisture and somewhat better potential storm-relative inflow in SW or W-central Nebraska. Still, the vacillation continued…but upon exiting the motel, I took one last look at the sfc map and chose a course WSW across the Sandhills, toward the prospective intersection of the (southern) moist axis and the dryline — near MHN.

The plan was to cruise W on NE-12 to VTN, look at updated data at the VTN library, then if not diverted by something really convincing, proceed S and W toward the MHN area. A serene late morning and midday drive ensued across the wetlands E of Niobrara, and the rolling plains between there and Naper. At Naper we had a cheap, greasy and unsatisfying lunch at the local cafe. [At least I was glad to be wearing an OU Sooner shirt there and all across Nebraska on this day!]

Rolling toward VTN on NE-12, we noticed towers going up distant W-WNW — apparently behind the dryline and in the southern part of the Black Hills. A likely dryline (turkey) tower could be seen far, far away to the SW, so many miles away it seemed lunar in distance. While in the VTN library, we noticed the line of towers that extended from near the dryline/moist axis intersection W of MHN, SW across east CO. That was the target area!

Upon leaving VTN we saw new, deep towers W of VTN that were closer (and that would develop into a storm complex along the NE/SD border). Nonetheless, we chose to stick to the forecast, plow along two cross-sections of the Sandhills and go after the storm that eventually developed from that clump of TCu and turkey towers W of MHN. Wheeling S then W through Thedford, the intermittent glimpses afforded by the dunes revealed the largest, darkest area of convection S of NE Highway 2, and a smaller anvil canopy just N of the road. Both cumulonimbi were well separated from the big area of storms farther S, in NE CO and the IML/OGA region, and would remain so. We had the discrete young supercells we wanted, but curse those Sandhills for viewing them!

Because the roads in the Sandhills follow valleys, you’re almost never above surrounding terrain. Even when cresting hills, you’re still lower than nearly all nearby dune ridges. This was a long-known hassle of chasing in those parts, but still, an irritant no less. We had intermittent views of the base of the northern (smaller) storm N of NE-2, and it had a small wall cloud and miniature forward-flank precip area for about 30 minutes before stringing out into oblivion. Them there was one! By process of elimination, our intercept target narrowed.

The same sickly fate wouldn’t meet the southern storm, which was drifting NNE across a vast roadless area WSW of Hyannis. We weren’t confident in finding a viewing spot along NE-2 W of Hyannis, so we turned S to a point 15 S of town where the dunes to the W were at least low enough above the horizon to see some of the area under the storm’s bottom (wide angle). That was the closes we could get, at least without a helicopter or an Abrams tank!

A broad rain-free updraft base and anvil field made for nice, classical, and distant (Crowtheresque) structure shots. Meanwhile, a crisp mammatus field streaming ENE from the storm yielded even better photography, looking in wide-angle views (vertical and horizontal several minutes apart) down a long ribbon of highway to the next dune crest.

I didn’t fire up “NetThreat” until we already had been sitting at that vantage for a spell, and even then, mainly out of curiosity about my storm’s radar structure, or at least that which can be inferred from what Rich T refers to as “cartoon radar” in Baron’s oversmoothed composite reflectivity presentation. Even at that resolution, a fairly well defined hook had begun to protrude S of the main core during the visual appearance of fairly precip-free, robust, tiered updraft. Then, as if on cue and within 10-15 minutes, the storm developed a good deal of precip around the N and W side of the heretofore rain-free base (wide-angle view), and another shallow wall cloud developed with more obvious cloud-base rotation (as seen through zoom lenses and binoculars…yes, binoculars).

Within a few minutes more, around 1758 CDT, a distinctive, rotating lowering (contrast-enhanced zoom) developed from two or three chunks of scud orbiting a common vertical axis, below that wall cloud. It persisted for 3-4 minutes while we prepared to find a better view. This possibly tornadic lowering got smoother and more symmetric, continued to rotate, and extended below the top of the dune line to our W (wide angle shot). It was in about the right location in a storm-relative sense. But because of the terrain’s truculent truncation of our view, we had no way to provide certain confirmation or refutation of what may have been going on beneath.

Was this (see highly enhanced crop) a tornado or not? Given where we were and where it probably was (scrubby dune fields somewhere over eastern Garden County or southwestern Grant County), the answer may never be known.

During our trek back N, brief glances at the base revealed the lowering went away, and the storm was filling in with more rain. Meanwhile WxWorx was showing the structure getting messier; and a string of very high based, initially not surface-rooted convection that developed E of the storm was hurling both raindrops and CGs down around us. Yecch! But the ugly duckling soon would metamorphose into a beautiful swan.

We found another vantage on the Evans Ranch road just N of Hyannis, whereupon a visual delight unfolded. A new storm developed just to our E from that initially elevated string-cheese, and intensified into a greenish, elliptical and high-based HP. For half an hour or more, sinuous strands and ribbons of laminar cloud material surrounded the core and painted a picturesque, otherwordly blend of colors and textures over those grassy green dunes (looking SW and looking NW). The funky cloud displays continued as the storm retrograded toward the NNW at a rate faster than the slow advance of its gust front. The net effect was fascinating too: The gust front was moving out of the storm and in our direction, while retreating away from us! Out of many hundreds of storm intercepts in over 20 years, I can’t recall experiencing that before.

Once that storm backed farther away and weakened, we headed S toward food and lodging in OGA. In the way stood a severe storm anchored by a potent looking updraft, but it quickly shriveled as the bigger complex farther S (in northern CO) grew upscale. Here’s a shot of the final “chicken neck” stage of that updraft, seeming to rise like a geyser from the muscular landscape of the Sandhills’ shortgrass prairie.

No longer impeded by the intervening storm, we cruised S through the Arthur area toward the back side of the burgeoning MCS, stopping at a couple of points N of the McConaughy dam to watch, photograph and appreciate a rainbow beyond wildflowers, a scrambled-egg sky to the S just before sunset (Lake McConaughy is in the far background), and then, gently cloud-filtered sunset colors to the SE and to the SW.

We checked into our motel at OGA, then a late, fast-food meal before discovering that the day’s action wasn’t finished! Some new storms developed along the NW edge of the MCS, to our SW, then rolled toward us. Getting a few shots of their CGs behind the water tower of Ogallala, which is spotlit at night and decorated like ET’s alien vessel, was icing on the cake (shhh…here’s my favorite). Add to that the ongoing deluge and show of CGs and crawlers as I typed much of this summary around midnight that night — in the N rim of a flood producing MCS between OGA, LBF and IML. This capped off a chase day that was frustrating at times but far more enjoyable than not in the end.

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