Wyoming to North Dakota via a Nebraska/South Dakota Dryline

August 5, 2012 by · Comments Off on Wyoming to North Dakota via a Nebraska/South Dakota Dryline
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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.

Three main target areas presented themselves to us as we pulled out of CYS on a sunny morning:

    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.

White Buffalo, White Tornado

July 10, 2010 by · Comments Off on White Buffalo, White Tornado
Filed under: Summary 

Glenfield ND to Crookston MN, 17 Jun 10

SHORT: Intercepted a string of mini-supercells across eastern ND into NW MN, with several funnels and one confirmed tornado.

LONG: We had arrived in PIR late the night before — tired, frustrated and hungry after being stonewalled on the wrong side of the Dupree storm, and took awhile to get to sleep. Somehow we still awoke well-rested and ready to head farther NE to this day’s most preferred target area — west of the trees in the wide-open flatlands of eastern ND. While big supercells and tornadoes certainly seemed possible in central MN, it was no closer, with more impediments to viewing from trees and hills. So instead of what was “synoptically evident”, we decided to play the alternative target just NE of where the arc of fast-moving, cold-core supercells presumably would fire, the strategy being to wait for those storms to mature. We also were hoping for enough separation between such storms for a “picket fence” intercept strategy — whereby the observer find a good road aligned perpendicular to expected storm motion, lets one pass, moves E, watches the next pass, and so forth. That was the ideal.

The storms themselves had slightly different ideas.

After heading to ABR to meet up with the late-breakfast devouring “3 Dudes and 2 Dogs” chase team, we all headed N toward JMS, our first sojourn into North Dakota in several years. Surface winds in the narrow warm sector were roaring from the SE, the cumuli above roaring S to N, and higher clouds SW-NE, visually sculpting a mighty fine deep-layer shear pattern ideally suited for supercells. An early storm fired NW of JMS, well out of our reach, and raced N, apparently producing a tornado or two despite being N of the warm front. Storms about to fire near us, along the nose of the dry punch, and just S of the warm front, would have just as much shear and more instability to work with. Optimism ran high, despite the previous day’s misfortunes (the 3 Dudes and 2 Dogs had arrived at the Dupree storm on the right side, but too late).

As we fueled in JMS, an arc of towers went up S through SW of us on that hybrid dryline/cold front, just as anticipated. We initially headed E of torn, but changed our minds about using I-94 as the picket road, and backtracked to get NNW on US-218 to Carrington. In doing so, we all saw the beautiful albino bison White Cloud, start attraction of the Buffalo Museum there at JMS. From Carrington, we turned E on ND-200 toward Glenfield, to allow storms their maturation time. While waiting, I whipped out the shovel and grabbed a couple of bucketfuls of North Dakota’s richest, deep-black glacial soil for use in my vegetable garden. The air was ridiculously moist — dew points well into the 70s F — with high RH thanks to the cooling from deepening anvil shadows produced by the oncoming convective arc. I remarked to the Dudes that it smelled like the ocean outside, and for good reason: just as everywhere else we had been since the Texas Panhandle, fields were saturated and often ponded, with large areas of prairie farmland under shallow, standing water.

This also created an ideal setting for massive clouds of voracious mosquitoes. In dense hordes, they rose from the inundated fields with one aspiration — sucking all possible blood out of unprotected storm observers. These specimens were quite large and rather slow-moving too, easy to snatch by hand and crush, unlike the zippy little culexes and Asian tiger mosquitoes we’re used to down here. As we watched the storms approach, Elke and the Dudes saw the pests banging against windows and windshields of our parked vehicles and stayed inside, not wishing to sacrifice gallons of Type A. I remained outside the entire time, and got bit…not a single time! The SE and E gradient wind, in whose gusts I had trouble maintaining balance, was so strong that it blew the mosquitoes off and past me before they had a chance to bite. Imagine you’re the “skeeter”. You see this huge host with abundant food supply, big areas of exposed skin on arms, face and neck, try to land, and…next thing you know, you’re in the air again, rocketing away from that delicious-looking host despite your fastest wing beats in that direction. I loved the concept, and relished the rare experience of laughing at the stream of hundreds upon hundreds of the pests as they tried in vain to attack me.

Meanwhile the arc of convection was headed NNE at us, maturing, and growing too much, with too many storms. Each cell had very little separation from the next on radar, leaving only a needle’s-eye of viewing opportunity into its mesocyclonic region. Each also was exhibiting enough rotation to be tornado-warned, and several of them produced funnels — some we saw, some we didn’t. We had our first good view of one of the mini-supercells’ updraft areas just W of Glenfield. It rapidly approached from the SW, and as it got to within a few miles, maintained a well-defined clear slot and ragged base with occasional areas of rotation. That was all it could do before getting rain-wrapped (looking WSW at a N-moving storm with meso on its SE side). As we leapfrogged E on ND-200, each successive storm farther E rained into the inflow of the previous, and also slowed us some with portions of its forward-flank core. The storms were translating so fast that these cores were unavoidable, but at least they didn’t contain much hail.

A few of the updrafts, occupying very narrow gap areas between cells, produced small, short-lived funnels — some so quick to develop and dissipate that there wasn’t time to stop and shoot, or even to raise a camera and shoot if stopped. Cloud-base motions in the updraft areas, even without funnels, were extremely wild and chaotic, with little in the way of well-defined structure. Zigzagging mostly E but sometimes N, we did manage to stop at one storm gap between Hatton and Reynolds where two small, adjacent but visually separated updraft areas each produced funnels at the same time, and we did manage to get photos (looking SW and looking SSE, both less than a mile away and moving fast toward the N). In fact, look closely at the left upper edge of the photo of the first funnel, and you’ll see the second (unintended). Both also dissipated quickly after rapid, corkscrewing contortions, with no evidence of ground circulation beneath.

As we crossed the river into Minnesota, S of GFK, the storm arc finally got ahead of us, and the storm observing was obviously about to end. We parked 1/2-mile S of the intersection of MN-9 and a county road headed S toward Eldred, 3 SSE of Fisher, to watch assorted small updraft areas all along the backside of the arc as they hurtled away from us. In this wide-angle shot, looking N, note the small, high-based funnel above and to the left of the road, but also, the ragged little updraft to the right of the road. These updraft areas were just a small part of a string of them extending up into a really fascinating deck of undular “warm advection” clouds along the S side of the storm arc.

As that anemic-looking updraft area moved NNE of us, its rotation tightened markedly, and a funnel appeared beneath. By this image, at 1754 CDT, we were pretty confident that it was a tornado; and later independent corroboration confirmed such. The condensation funnel became fuzzy and somewhat rain-wrapped, but reappeared as a ghostly, front-lit and more obvious tornado, its estimated location ~2 E of Fisher. We had seen a white buffalo and a white tornado in the same day! I tried to call this in to GFK, but as happened an annoying number of times this year while watching a tornado, I found “No Service” on my phone’s indicator. Fortunately, I was able to get the delayed report to them from a later fuel stop in East Grand Forks.

We gave up the hunt N of Crookston on US-75, shortly after passing a mileage sign that read, “Canada 93”. That’s when an OK resident knows he’s really far N, and a long way from home. That night, swimming in a hotel’s indoor pool at 11 p.m. with twilight visible outside, was a different experience!

All of us had a good, celebratory steak dinner at Al’s in Grand Forks. The Dudes and Dogs had to be in OKC day after next, and headed S to FSD for the night; we stayed in GFK and had a nice visit to the NWS office at GFK the next morning.

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