2010 Chase Season Dénouement
22 Jun 2010
Southeast WY to North Platte NEb
SHORT: Outflow-dominant supercell observed twice — once in SE WY and another in NEb Panhandle. Gorgeous sunset supercell S of Paxton NEb.
LONG: We were hoping for one final photogenic supercell for our chase vacation, and instead got two.
A piping hot lunch at a local cafe in downtown Sidney NEb, featuring a platter of smashed and fried Rocky Mountain oysters, settled down hunger’s restlessness just long enough for us to watch satellite imagery on the mobile phone, seeking first signs of convective initiation on the Laramie Range to our W. This area would experience favorable upslope flow, decent low-level shear and deep-layer winds, along with sustained surface heating in the absence of any appreciable, antecedent cloud cover, but moisture seemed a tad on the scant side. Once the first towers started to fire NW of CYS, we hopped onto I-80 and roared westward.
By the time we got to Pine Bluffs WY, deep towers were visible with glaciation to our NW. We could see the cloud bases easily, so we fueled at a truck stop there as I chugged down a cold, delicious A&W float. I also reserved a room in LBF for the night using a combination of forecast storm motion and positioning needed to go back home the next day, while watching for a storm to congeal and organize from the agitated area. Soon, it did, and we took off W through Burns and then N, retracing in reverse a segment of our chase path from the tornadic Chugwater event two days prior.
True to the lack of more robust moisture, the bases seemed uncomfortably high, and I was troubled further by how fast the cells started moving E off the mountains as we approached. Was the convection already spewing outflow? Yes! We barely beat the storm to the intersection of WY-213 and WY-216 W of Albin, near which I shot this photo looking W. Yes, there were updraft bases all right, but they were being undercut very quickly by wickedly cold currents hurtling SE from the precip cores. We headed E on 216 to Albin, having to make a decision there either to:
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1. Take unpaved back roads and stay closer to an outflow-surfing wind and ice machine, risking its outrunning us for good somewhere not far E of the WY-NEb border, or
2. Shoot back down to I-90 and bust eastward at higher legal speeds so we could stay abeam and eventually get back ahead of the storm on a north road.
Although I’ve seldom seen such an outflow-dominant storm recover to produce tornadoes, it has happened on one occasion. Furthermore, such storms can produce interesting and sometimes beautiful cloud formations, especially out on the high plains. The decision was easy.
Meanwhile, before zooming down to the Interstate, we watched the storm cross the road to our N, spying a suspicious-looking but very short-lived formation buried in a mesocyclonic notch region (enhanced crop-n-zoom of previous image). That feature quickly vanished, and the whole messy and wild-looking process roared past.
By the time we got just the few miles S to I-80, the storm already had gotten well off to the NE, brilliantly festooning a deep blue sky (wide-angle view from I-90 near the border), with a high and ragged base visible on the trailing flank. That, along with the main updraft base of the storm to our left, were visible as we cruised E to Sidney, then N toward Gurley — in the process retracing a late-day segment of our trek from the previous season’s intercept of the LaGrange WY supercell. For our nearly continuous view of the updraft while driving, and several chasers who were closer at that time and didn’t see any tornado, I had to question the “sheriffnado” reports just E of the border in NEb.
We got directly ahead of the storm again E of Gurley, watching its somewhat-lower base with a small, shallow wall cloud developing to our WNW (wide-angle view) while a deck of low clouds formed overhead. The storm itself was decelerating markedly, and its own outflow boundary appeared to outrun its main reflectivity area (and mesocyclone aloft). I got a dread that the supercell wouldn’t last much longer; and it certainly did not. A zoom view shows the wall cloud that was surrounded by translucent precip. Within minutes, a fuzzy gray bowl of precip appeared right in and under the wall cloud, descending and expanding and obliterating the wall cloud as it reached the ground, and making a splendid example of a tornado look-alike.
Was this a descending reflectivity core (DRC) that came down in a very deleterious place for any low-level mesocyclone’s development and survival? It sure seemed as such. Here’s the view 3 minutes later, when the precip core further expanded and utterly obliterated the cloud base where the wall cloud previously had dangled. Within 11 minutes more, the outflow had gone past, the low clouds cleared away to reveal an astonishingly rapid storm demise!
Thinking that was it for our chase season, we headed E toward LBF, only to see a stunning and spectacular convective eruption to our SE, S of Paxton, beneath a waxing gibbous moon and shortly before sunset. As this storm evolved into a short-lived supercell, we admired the amazing spectacle from a corn field a couple of miles S of the Interstate, until an inverse relationship between amount of sunlight and mosquitoes hastened our resumption of the trip. What a wonderful way to close out the last chase of Spring 2010!
When we settled into our room in LBF, the clerk remembered my call and said we were smart to do what we did many hours before; all the rooms in LBF were booked up solid! After 11 p.m., we noticed a dramatic increase in lightning to our N-W, as storms erupted along the outflow boundary. While cruising S of town in search of a good vantage in that direction, the storms weakened again, precluding any decent lightning photo opportunities, though we did salvage a nice look at lunar crepusculars around an altocumulus deck.
This was a rewarding day, one that left us in ideal geographic position to do something we had wanted for a long time: pick up a stone fencepost from one of the quarries near RSL. It would be right along the way home the following day. Our adventure in doing so was a marvelous glimpse of Americana, chronicled in more detail in this BLOG entry. The dénouement had been written on our chase season – one that was, at times, agonizingly frustrating, and at others, as fulfilling as can be. What adventures await in 2011?
Clam’s Foot Surfer
Dumas TX and vicinity
12 Jun 10
SHORT: Observed outflow-dominant line E of Dumas, elevated stage of supercell SW of Dumas that hailed over us at dinner.
LONG:
Elke and I began the day with a cold breakfast at our Burlington motel, joined by Chuck and Teresa Robertson, then Matt Crowther and Vince Miller, all of whom also had intercepted the Limon-area supercells the day before. The cold front was surging farther S, faster than forecast the previous day, so we all had to get out of town soon and jaunt down south to the Panhandles. For Chuck and his lovely bride, who live in the northeastern TX Panhandle, it would be a return home, with storms along the way.
After a couple of hours on the road, we stopped to pick up some provisions at the Wal-Mart in Lamar CO. On the way to the rear latrine, I spotted a familiar human form — there was Vince, picking out a shirt in the clothing section! What are the odds? A short chat with him and Matt outside, and we all were back on the road again. We wouldn’t see either of them the remainder of the day. Still, in storm observing, such are the unplanned, chance encounters one can have with familiar old friends and acquaintances.
By the time we got to Boise City OK, storms already were firing along the cold front to our S and SE in the TX Panhandle, with big towers erupting beyond the cool, foggy haze. The most robust of those went through a briefly tornadic supercell phase well before we could get to it, then turned into a large HP mess. We thought about “rounding the corner” on it E of Dumas, but by the time we committed to that plan and got near it, the entire complex had degenerated into this rather amorphous, outflow-spewing mess, all while dumping nearly a foot of rain from train-echoes near Morse.
Another fun serendipity of storm observing is being in the same place twice, hundreds of miles from home, on different days and different storms, in the same season. Such was the case with the last photo, which I took on FM-1060 while less than a hundred yards from where I shot the mesocyclonic merry-go-round E of Dumas the previous month (see You Decide, 18 May 10). We retraced steps from that amazing May day eastward through Stinnett and north a few miles, but without such intense atmospheric results.
While shooting time lapses N of Stinnett, David Hoadley pulled up and chatted with us for awhile in the cool outflow. It’s always a pleasure to see Dave again, as I seem to do about once a season at some random rural pull-off near a storm. Some new cells were trying to fire south of the outflow boundary and W-NW of AMA, so Dave and I agreed that was the only remaining viable target, and parted ways, independently heading the same general direction. Along the way back to Dumas, Elke and I stopped to shoot a couple of peculiar, fascinatingly illuminated and somewhat convective scud formations (first and second).
One longer-lived cell had crossed over the arching outflow boundary SW of Dumas but remained intense on radar, so after grabbing a motel room there, we drove a couple of miles S of town to take an unobstructed look. We still were in cold NE outflow from the massive complex to our NE, and this storm was obviously elevated at the time, exhibiting laminar formations and riding atop an elongated, clam’s-foot cloud formation (wide-angle view looking WSW) as the chill breeze at our backs strengthened further. Ribbed texturing to the main low-cloud band, glowing in twice-reflected, late-afternoon light, formed an uncommon and striking visual backdrop for the wind farm SW of town.
Thinking somewhat erroneously that the storm would remain elevated, we ate dinner in Dumas as it rolled over us, profusely peppering the restaurant windows with a protracted blast of hail near an inch in diameter. I was tempted to run out and grab some hailstones as ice for my drink, though the Moore County Health Department might not have approved of this item on the menu. It turns out that the supercell backbuilt and right-moved, once again getting close to the eastern segment of the curving boundary, and becoming surface-based again to our E, after it left town. We finished supper and headed a few miles SW of Dumas hoping for sunset photography, but with all the various clouds in the way, all we could salvage was some twilight pastels over ripened wheat.
We slept well that night, knowing that the next days’ target would be in the Panhandle also, but not knowing that we would see both a pretty tornado-producing supercell and the largest amount of standing water we’ve ever witnessed on a High Plains storm intercept.