Last Chance near Last Chance

March 11, 2014 by · Comments Off
Filed under: Summary 

Wiggins to Cope CO
23 Jun 13

SHORT: Remained ahead of northeast CO convection as it metamorphosed from early, fuzzy slop near Hoyt and Wiggins to a supercell-infused squall line between Woodrow and Cope with several photogenic and beautiful scenes.

LONG:
Final chase days of the season usually are known in advance to us, because we tend to take our Great Plains trips near the end of the traditional spring storm-observing season in a fixed time slot. As such, many last-chance chase days are known as such that morning, if not before. They can get sentimental. We focus and reflect on the possibilities with a renewed sense of wonder and anticipation, knowing this is the final opportunity for the season and probably the year (save the opportunistic fall chase that happens once every five years or so).

Northeastern Colorado was the target area, with the old outflow boundary from the previous day’s convection in WY and NEb having settled southward into eastern CO and weakened, leaving behind some upslope flow into the Front Range, reduced low-level moisture compared to the previous day in WY, and weaker (but still sufficient) shear for supercells. Cloud bases were likely to be high, with strong potential for outflow dominance and meager, conditional tornado risk.

Yet these reduced-moisture, upslope-flow days often yield scenic skyscapes festooned with interesting storm clouds of various types–especially if one is patient with often ragged, nebulous early convection and keeps apace until it organizes. Forecast storm motion toward the CO/KS border area also likely would take us toward I-70 and a one-day drive home the following day.

Our weather-dictated itinerary the previous several days had taken us from MT-ND-SD-WY-NEb, where we were starting the morning in Kimball, right by the CO border. It was as if a storm-intercept guide had been navigating us gradually homeward with amazing skies and fantastic experiences all along the journey. How fortunate! And here we were, ready to partake of one more afternoon of beautiful storms on the way home.

Proximity to the target area allowed plenty of time to eat brunch, analyze data, and watch the southwestern horizons. Early-afternoon towers erupting to our SW, in northern CO, were easy to see from IBM, so we cruised easily S to Ft. Morgan and saw the high, fuzzy bases even from there. Continuing SW through Wiggins toward Hoyt, we got a nice close-up view of the virga factories, appreciating the majesty of the High Plains even under soft storms, on scales large and small. Small? Oh yes. We enjoyed watching birds that Elke couldn’t identify hop through the stubbled cornfields of 2012, skittering along at a deliberate clip, pecking away at bugs, seeds, or other material unseen.

Next, we retraced the path back up to Ft. Morgan, then veered southward to get on proper road options that would allow us to stay ahead of whatever would evolve from the growing multicell complex to our W. While doing so, the convection slowly acquired visible, if still high, updraft bases, which gradually grew in areal extent and number along with CG flashes. I’ve seen this before. Usually, in these favorable deep-shear profiles, a supercell will develop unless the entire mass is blasted asunder in infancy by cold outflow. That wasn’t happening; the cores offered only feeble density currents, judging by the lack of proximal dust plumes.

Jaunting off the main highway between Brush and Woodrow, a couple miles down a dead-end dirt road, we found a good place right at the terminus where we could photograph wild sunflowers and a wild storm. Cores grew. Updrafts grew in front of the cores. Inflow strengthened. The whole raggedly beautiful storm pile got better-organized and backbuilt before our very eyes, ears and nostrils, as revealed during a stop just S of Woodrow.

East on US-36 4 miles out of Last Chance, and another mile N on a (barely) paved side road, led us to temporary solitude: us, a photogenic abandoned farmstead and the rampart of storms in the west. Whoa! What’s that back there to the NW behind the old house? You guessed it, brother–not just an old storage building, but a high-based wall cloud and mesocyclone.

Although short-lived, the line-embedded supercell provided some striking, picturesque scenery as it headed ENE, before getting disorganized in favor of other updrafts to our own W and SW. While watching that spectacle, a ranch mom and her kids drove up on an ATV to make sure we were OK; we chatted with them awhile before one of the little ones drove them all back to their house on the four-wheeler. Encroaching storms sent us eastward to the Anton area.

Even though the whole complex was becoming increasingly outflow-dominant in the fading daylight, a marvelous episode of deep twilight blues, slate to marine in hue, sandwiched layers of laminar cloud material to the SWto the Nto the SW again. What a show! At least transiently intense, somewhat supercellular updrafts kept forming along its leading edge, with assorted notches (some rather sparkly!) and other circulations of varying scales.

Admiring the scene, we also noticed that the base surfing outflow to our SW was becoming increasingly circular, quickly. Within less than 30 seconds, and about a mile away (closer than it appears in this wide-angle shot), a small but tightly rotating wall cloud formed from a pre-existing, seemingly benign lowering under that base (annotated version). Quickly, dust stopped then rose beneath. The circulation started to hook toward its NE–right at us. What had been light westerly (but mild) outflow winds backed and accelerated from the ESE. Time to bail out of there!

Although I doubted any substantial tornado could develop in this circumstance, I didn’t want to be the guinea pig to test that hypothesis. Even though we only had to go less than 1/4 mile to get back on US-36 and gun it eastward, we still were not comfortably relaxed–no thoughts of rocking in hammocks beneath Caribbean tiki huts while sipping dewy beverages. Instead, the rising pile of dust, under a small area of cloud-base rotation, with screaming inflow winds, nearly overtook us. I can’t say for certain if that circulation ever tightened into a full-fledged tornado, but if not, it came precariously close.

Just as fast as it formed, deeper outflow from the west crashed through the feature and tore it up, leaving behind a dispersive dust pall over the highway behind us as we gained a few miles of headway. With daylight fading fast and eyelids growing heavier, we watched the mess become more linear and turned S toward I-70, out of the way of all storms. A night at our favorite motel in ITR, lightning flickering off to the N and NE, closed out our 2014 storm-intercept season with a lullaby after the atmosphere’s final flourish.

Driving home the next day, we reflected and remembered. What a season it was…rewarding for us photographically, educationally and spiritually through the unfailingly transcendent experience of wonder and awe before storm-tossed Great Plains skies. The sting of major missed tornado events practically in our backyard was healed during over half an hour of observing from one spot a nearly stationary, violent, yet ultimately harmless tornado in open country of northern Kansas. We made some great memories amidst the solitude of the prairies from North Texas to central Montana. With heavy hearts, we also thought of old friends killed just over three weeks prior by the vaporous forms we seek, on a day when we didn’t head out. Here’s to a safer and much less destructive, yet more photogenic and inspiring, 2014 storm season to come.

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Our PING trail for this day. [PING date is ending date in UTC.]

Buried Tornadoes by the Border

February 28, 2014 by · 1 Comment
Filed under: Summary 

Chugwater WY to Kimball NE
22 Jun 13

SHORT: Intercepted 2 supercells in SE WY, first photogenic, second became dark and nasty HP with about two tornadoes buried inside and barely/intermittently visible. Lightning and photogenic outflow formations with tail end of resulting MCS in NEb Panhandle.

LONG:
Having made a full-circle back to Chadron from five days before, we did a little late-morning photography of abandoned antique vehicles that we had seen previously, then bid farewell to our favorite north-central High Plains town to head SW. We targeted as promising of an upslope-flow supercell scenario in southeastern WY as you’ll ever see, realistically. The previous day’s boundary was shunted southward toward the Cheyenne ridge, flow behind it veering throughout the day to both advect unusually rich low-level moisture upslope (beneath favorably strong midlevel winds) and yield a big hodograph. That moist air rising up the Laramies would do the heavy lifting, with help from hours of sunshine. Since we actually weren’t far away and were leaving before noon, I was as confident in seeing a tornadic storm on this day as any the entire June trip. Slap those hands together, fill the tank, hit the road, and get ready to rumble under some spinning sky.

Supercells rolling off the Laramie Mountains under similar flow patterns and even less moisture have produced delicious tornadoes on several occasions in the last 15 years. For some reason, we (and I, before marrying Elke) had been late to the party for most of them, either missing the tubes or barely catching their end stages. The 2010 Chugwater storm was, of course, a wonderful exception. Even early initiation wouldn’t be a problem, given the long N-S roads of eastern WY and the good visibility away from the E slopes of the escarpment between Hawk Springs and Chugwater.

Over the hills and into Wyoming we went, fueling in Lusk under the midday sun as anvils began streaming off the northern limb of the Laramies. This was early initiation indeed…for which (for once) we were ready! The most vigorous cell, near Dwyer, appeared to be turning right and organizing into a supercell fairly quickly. Fortunately, it was aiming right down US-26 toward the Lingle area, where getting ahead of it would be easy. No wondering what was over the horizon, no driving 150 miles after an early-forming Wyoming storm already in progress! When we got just S of Lingle, there it was, in youthful supercellular splendor, to our W.

The supercell traveled ESE as another developed to its SW, with rain from the newer storm cascading into the established supercell‘s upshear region. After briefly encountering fellow storm observers Vince Miller and Matt Crowther, we moved a few miles S, stopping briefly to watch a beautiful phase of the otherwise shrinking and rising cloud-base configuration, characterized by a clear slot with tightening rotation. Nothing came of that; the occlusion downdraft cut too tightly into the rotation area and dry entrainment eroded what was left. The older cell then slowly weakened at the expense of the rapidly strengthening upshear storm, and we headed S toward Veteran to get in front of the latter.

What we found there was an entirely new animal–one that would turn into a menacing, growling, teeth-baring, attacking beast in short order. Looking SW at the reasonably large updraft area, ragged, slowly rotating shelf/wall cloud hybrid and dense core, it was easy to predict that this beautiful mess of a storm would become an HP in short order. Since the entire storm was moving ESE, this was an unsustainable viewing position; the forward-flank core and its hail would impose its will on us if we stayed put much longer.

A quick zigzag E and S out of the Veteran/Yoder area took us onto US-85 NE of Hawk Springs and NNE of LaGrange. We had to bolt S ahead of the strengthening mesocyclone to our SW in order to take the east option toward WY-151/NEb-88. First, however, we had a few minutes to stop, observe and admire a very rapidly intensifying circulation–a photogenic and menacing wall cloud that quickly evolved into wide, rapidly rotating, nearly ground-scraping bowl, a mesocyclone that clearly meant serious business. A small funnel briefly whizzed around the left (SE) side of the bowl, but with no clearly discernible debris beneath. The entire spinning mass of gas still was moving ESE and we were NE of it. No time to tarry…we had to go!

We skirted the E edge of the orbiting precip curtains from N-S as the mesocyclone quickly wrapped in rain and the storm took on a mean, nasty HP form. I’m used to tangling with those in north TX, but not on the more road-sparse plains of the WY-NEb border. Fortunately the east-151/88 option was conveniently located to offer a chance to get safely ahead of the whirling dervish for awhile, albeit in the eventual path. A brief glance at radar indicated a rapidly tightening and potentially tornadic mesocyclone to our NW as we approached the border. I stopped there to observe and thought I might have seen the tornado (see photos in table below), one about which I was more certain that night, after viewing the photos via camera display and talking with the NWS office. Given its S of E movement, we couldn’t stay too long.

After charging E across the border, after a mesocyclonic cycle, and while I still was driving to gain some distance, Elke took a look at the radar display and saw this rather alarming SRM signature a few miles to our NW. There was obviously another tornado somewhere in that dark precip mass–and likely a significant, potentially violent vortex to boot! It also was moving ESE, meaning we would have to stair-step along the W-E highway in multiple stops to stay safely ahead of it, and of the wrapping precip.

Needless to say, I slowed down really quickly and turned into a northward-directed side road to stare hard into the rotating cylinder of precip. At times, during the second of two different stops along NEb-88, I could make out the tornado ‘s condensation funnel–briefly, barely but confidently. We stopped again after turning S on NE-71 past Harrisburg.

What follows is a chronological table of links to a selection of photos taken at the stops, looking NW at first, then WNW. The photos show the region as it looked with eyeballs (“PHOTO”), heavily enhanced (“ENHCD”) and in a few cases, enhanced and annotated (“ANNOT”) to bring out the tornado where possible, and to illustrate the motion. Curved arrows on some ANNOT images show the area of very intense rotation. All of these were processed within a few weeks after returning and provided to the CYS WFO for their evaluation. [I have them prelim track and time estimates the same night via phone call using adjusted camera times (camera was 4 minutes fast).]

[Please scroll down to see the tornado-photo table and the rest of the post. I don't know how to fix this gap.]
































































Sequence Number & Viewing Location

Normal and Edited Photos

1. 2 W WY/NE Border, WY-151 PHOTO ENHCD ANNOT
2. 2 W WY/NE Border, WY-151 PHOTO ENHCD ANNOT
3. 2 W WY/NE Border, WY-151 PHOTO ENHCD ANNOT
4. 3 E Stegall S Rd on NE-88 PHOTO NO ENHCD NO ANNOT
5. 3 E Stegall S Rd on NE-88 PHOTO ENHCD ANNOT
6. 3 E Stegall S Rd on NE-88 PHOTO ENHCD ANNOT
7. 3 E Stegall S Rd on NE-88 PHOTO ENHCD ANNOT
8. 3 E Stegall S Rd on NE-88 PHOTO ENHCD ANNOT
9. 3 E Stegall S Rd on NE-88 PHOTO ENHCD ANNOT
10. 4 NE Harrisburg on NE-71 PHOTO ENHCD ANNOT

Because the tornado on the Wyoming side of the border (images 1-3) appeared to shrink and get deeply occluded into the precip, and because NWS CYS surveyed a distinct tornado track on the Nebraska side, I now very strongly believe (>95% certainty) that the Wyoming and Nebraska tornadoes were separate. On the Nebraska side–yes, there also was another dark, columnar area to the left (SW or WSW) of the tornado cyclone in a few images (mainly 4-5), but I could not tell what it was. The rotation of precip around the tornado in each photo was furious and obvious. Even when I couldn’t see the tornado at all (which was most of the time), there was no doubt of its presence.

Due to lack of visual continuity, I also can not state definitively if the Nebraska tornado was continuous between stops, or two separate events. NWS surveys indicated one path in Nebraska, so I’ll count this as a single, second tornado for now, given no firm evidence to the contrary. The tornado only hit a few things, earning an EF1 rating due to sparse/weak damage indicators. However, its WSR-88D radar signature is consistent with many strong to violent (EF3-4) events, based on a study underway by Bryan Smith and others at SPC. We’ll never know its true strength.

The tornado moved almost directly toward my position in image 9, but dissipated before it got to NE-71. By that time, we had bailed S, out of the way, and found a hilltop S of the 71/88 intersection. There, we tried to view the deeply occluded, embedded meso as it got thrust back out of the rear side of the precip area (enhanced. There may have been a weak tornadic (or nearly tornadic) circulation still going at that point (enhanced), as visible cloud-base rotation still was reasonably strong. I can’t say with complete certainty. By this time, a big gust front and shelf cloud had surged well ahead of the mesocyclone. The supercell was evolving into a linear structure with more storms erupting to the SW–we had an MCS and QLCS on our hands.

Plenty of daylight remained, so…time to go tail-chasing! We proceeded S to and past Kimball in search of a vantage, and found one 3 SSW of town on County road 28, right along the N side of Kimball airport (IBM). This was a treat! Even though the complex was decidedly outflow-dominant at this stage, its arcus underside and photogenic lightning were just plain fun to observe. The core passing to our N fired a good volume of electrical artillery from the same general area (including one whose most visible segment was “questionable”). One bright outlier, an outflow-influenced channel and a few other strikes followed as the core moved E. Meanwhile, the arcus’ underbelly passed overhead and to the S with fantastic sharpness to its turbulent texturing. What a crazy, interesting sky!

Ravenously hungry by now, and chilling uncomfortably from all the outflow, we snapped the shutters at a few more strikes from the last passing core, then headed into town for dinner. Amidst that huge and expansive puddle of outflow, we didn’t imagine that an updraft would blossom to the E that was surface-based, and produce a brief tornado (seen by a few observers still afield) before being undercut. That’s how it goes sometimes. While somewhat disappointed, we could live with it. We had seen some serious tornadic action already, and the hot pizza tasted mighty good going down. Here was one final look at the back side of the complex from the pizza-parlor’s parking lot, as the storms retreated into the suppertime sky.

After checking into the motel in Kimball, I got the tornado time/track info to the CYS WFO to the best extent possible, then reflected back upon another long but very rewarding chase day–one fruitful both photographically and in terms of both tornadic and nontornadic storm experiences. Forecast guidance also indicated that we had one more day of decent storm potential in CO before we had to head home. Our time in Montana was growing ever farther away in the rear-view.

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Our PING trail for this day. [PING date is ending date in UTC.]

Washing Two States

February 5, 2014 by · Comments Off
Filed under: Summary 

Central SD to Chadron NE
21 Jun 13

SHORT: Bypassed morning/mid-day SD MCS on its NW-W-SW side. Second MCS developed all around us in afternoon near CDR offering eccentric skies & flood.

LONG:
Recall, from the previous day’s summary, that I mentioned the unplanned adventures of storm-observing jaunts. Today was like that. We awoke in a Mobridge motel to a few itchy bites in places mosquitoes wouldn’t be able to access. We immediately suspected bedbugs, despite the lack thereof in the previous night’s customary inspections of beds and bedding. Another thorough inspection turned up none–so the mystery remains as to what got us. Whatever, it was time to get the hell out and not look back.

Laundry needed to be done anyway, given that we were in our last clean clothes. That process took longer than expected due to slow-working, money-sucking dryers; so we were stuck in MBG until that was done. This was important, as a complex of thunderstorms erupted early in the morning over the southern Black Hills (producing 4.25-inch hail!), expanding and rolling out across the Badlands area, sweeping ENE across much of central and southern SD, and treating storm observers near I-90 to a nice morning shelf-cloud display that we had to miss. All we saw, while laundry was going and while eating lunch, was the dark, amorphous gray mass of the MCS slowly shifting eastward across the southern sky.

Explosions of mid-late morning convection all over the target area seldom portend sweet supercellular tidings in the afternoon. The previous night’s thinking of a Badlands-area target would have to be revised southward, thanks to outflow from this big, unwelcome convective bomb. It was looking more and more probable that we needed to drive at least an hour or two farther SW then previously anticipated, into Nebraska. First, clean clothing and a hot meal took priority.

Lunch itself was very good–German food at a restaurant in town, just a couple of blocks from the washateria. The proprietor–a lady about my age but speaking with an odd Germanic accent, herded her own kids to and fro while serving meals and manning the register. Elke was perplexed by the accent too–not anything she was accustomed to hearing from a German or Austrian immigrant, yet decidedly of that origin. A later conversation with her revealed that she was a fourth-generation American and fully fluent in English, as had been all her ancestors in that area, but that conversational German had been passed down to her through each of four generations following 1800s immigration. That explained it–the pronunciations and cadences had been Americanized slowly over 100 years, but the words and sentences still were correct German. I wondered how she would sound to a Munich native if speaking that flavor of South Dakota German in Bavaria!

As we finished lunch, but before laundry was ready, supercells began to form ahead of the MCS, to our E and ESE and within an hour’s drive or so. This was mental torture. Yes, a quick eyeball modification of observed and forecast soundings indicated they were surface-based, as did the quick development of an intense, tornado-warned mesocyclone. These probably could have been intercepted, if not for our situation, and a tornado was reported with one of them before the cells all got absorbed into the northern fringes of what now was a raging bow echo. It wasn’t even after 1 p.m. yet! How could I get mad at missing weird midday tornado action ahead of an MCS? I didn’t.

By the time we got laundry done and packed, the supercell action was winding down, and the bowing complex had finished mowing across the PIR area and U-83 to our S. We headed down that road, through the back-side rain and lightning, admiring the oddly lit midday sky with darkness in the NE-E-SE and blue in the NW. At PIR we broke into milky skies of thin, training high clouds with slowly warming outflow and soft, stratified fuzz patches for low clouds.

Data checks showed the outflow boundary arching from about 80 miles S of us across Cherry County and into the Black Hills–still moving S but not very fast, and starting to cook in the heat of insolation on both sides. Vorticity source, vorticity source…hello! Despite the weaker-than-desired mid-up-er level winds farther S, perhaps a storm forming on or interacting with that boundary could spin up a needle-in-haystack surprise, if we caught it at the right place and time. Remember: I forecasted this.

Making the strategy work was another story altogether. It took us a few hours to zigzag our way across the reservations, through Martin SD, to Gordon NEb. By then, deep convective towers were apparent on both sides of the outflow boundary, which still was moving S about 10 mph but decelerating. The cap was weak and getting weaker, with very unusual 68-72-degree dew points along and S of the boundary. At that altitude, juice like that couldn’t be held down for long.

Moisture won–fast. In the relatively short time it took us to fuel up in Gordon, which was right on the boundary with nearly calm winds, the sky grew dark quickly, in several directions. Storms were blowing up to the NE, SE, S, and W–all at once, and acting like they wanted to merge. The most discrete, least messy area appeared to be to our W, toward CDR, which also was on the boundary. We headed that way, observing this storm rise with low, sopping-wet cloud features more suitable for Florida than northwestern Nebraska.

Somewhere back in the darkness to our E, in the messy storm mergers, a strong mesocyclone spun up on radar velocity displays, followed soon thereafter by a tornado warning and report…near Gordon, where we just had been! Determined not to get frustrated and whipsaw back after something that obviously would be transient (and turned out to be), we stayed with the convection near CDR. How could I get mad at missing weird cluster-embedded tornado action in what was becoming an MCS? I didn’t.

The sultry character of the air mass, in a place like this, was a dichotomy of two worlds–a vorticity-rich, humidity-laded gob of air that felt and smelled like a tropical depression, storms seemingly blossoming everywhere, but in a setting that hardly ever sees such conditions. I soaked in the familiar sensation from much lower latitudes–my mind singing, “5:00 somewhere”–until the outflow hit. That was that for that.

Storms were backbuilding to our WSW, just S of CDR, with outflow now past the town. Driving right by it anyway, and for good measure, we briefly stopped to secure a room for the night at our favorite motel there, the Westerner. The staff recognized me from my prior two visits this year, and was glad to get a weather report from their “expert storm-chaser guest”. Before we headed back out to get S of the backbuilding line, I told them to be ready for flooding rains, maybe some hail, but tornadoes looked unlikely in town.

By the time we got back out of town and onto the high ridge just to its S, tornadoes looked unlikely everywhere in the area. We could get back into the warm sector, but the storms were outflow-dominant, kicking big, ragged scud piles well ahead of any updrafts. There was a manifestation of the lack of more intense ambient shear. But hey…scud and outflow can be scenic, wondrous, captivating…and for several moments, these certainly were!

Uniquely arranged and oddly lit assemblies of landscape, low cloud banks and the background storm pall gave us a fine and fun time on the southern fringes of the Pine Ridge. Muted translucence from the late-day northwestern angle of the hidden sun, with deep cloud mass to the north and northeast, permitted an odd southern light to wash across the front faces of the low clouds, beneath and behind variegated slate tones aloft. That southern light reflected from the scud onto a part of the deck above, subtly illuminating it from beneath. Toss a green field foreground into the mix, and this was the fascinating result.

Gusting out as it sat nearly stationary to our N, the complex emptied its load on parts of CDR and areas uphill. Resulting torrents of flash-flood waters rolled off the southern hills and through the streets as motorists and motorcyclists casually ignored the latter-day mantra, “Turn around, don’t drown.”

The steak-and-sides dinner we had at Feiks (a recommended eatery) was bland, overcooked, overrated (by online reviewers) and overpriced, though service was attentive. We’ve had worse meals, but we likely won’t be going back there. By the time we were done, we were ready to return to the room, PING the last bits of rain, wind down for the night, recollect a long but worthwhile adventure, and imagine what the next day’s Wyoming upslope-flow action could bring with unusually rich low-level moisture involved.

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Our SD PING trail for this day. Our NEb PING trail for this day. [PING date is ending date in UTC.]

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