Altus Night Lightning

January 27, 2015 by · Comments Off on Altus Night Lightning
Filed under: Summary 

Altus OK
26 Apr 14

SHORT: Weak diurnal storms NW TX, brief supercell with lightning burst near LTS.

LONG:
Elke and I were off on this day, so we decided to go for a country drive to enjoy a fine Saturday afternoon and evening. That country drive involved heading SW from Norman, specifically to the warm sector ahead of the dryline near Vernon.

Because of a lack of richer moisture, prospects for anything tornadic didn’t look promising, unless a ribbon of higher mixing ratios could arrive just in time for that “magic window” of evening hours, when the boundary layer starts to decouple but the surface parcels still may be available to storm inflow. That scenario appears in wishes more than in reality in springtime regimes involving early-stage or incomplete moisture return, so we simply headed out in hopes of seeing some photogenic convection.

Wandering some backroads S of Vernon, we saw several nondescript cells bubble up and down in a SSW-NNE-oriented train. Most appeared rather mushy, befitting the lack of more intense CAPE, and didn’t exhibit any structure that compelled me to take more than a few test shots to make sure the camera was working. Still, we found a couple of remote spots away from highway traffic and enjoyed some time in the great Plains wind, as we enjoy every spring.

As the sun set, a newer round of storms was firing on the retreating dryline farther W–mainly SSW of CDS. We headed back into Vernon for some dinner at a greasy-spoon cafe, monitoring convective trends and plotting a course to observe the most intense cell after dark near LTS (an easy drive to the N) if it survived. By the time we got to LTS, the storm had been a marginal supercell but already was weakening, and another one mostly hidden to its NW was ramping up, moving mostly away from us, and starting to produce hail.

Regardless, we parked off a dark dirt road a couple miles SW of town and watched the slowly decaying original storm sail NNE to our SW, W and N, producing a few photogenic lightning flashes along the way. The second of them that I chose to keep (above in the header, and linked here), was the most fascinating. It appears to be a downward-directed attempt at a step leader that never contacted the ground, then got lit up as a secondary branch by a conduction connection (crawler style) somewhere deep in the cloud material above. The groundward-aimed scythe shape, as viewed laterally, makes me wonder how it would have appeared to a fortunate observer standing directly beneath–fortunate not to have been touched by the leader!

A few more flashes and the storm was done…and so were we. We headed home after a decidedly stress-free storm-observing trip having spent plenty of quality hours traveling together as a happily married couple.

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

Those Northern Plains Convective Skies

December 21, 2012 by · Comments Off on Those Northern Plains Convective Skies
Filed under: Summary 

Medora to Hettinger ND, Lemmon SD
13 Jun 12

SHORT: Rewarding day considering low expectations. Scenic initiation over badlands of Theodore Roosevelt NP. Intercepted subsequent splitting storms along ND-SD line, with dominance of slight leftward motion. Ended chase on E end of high-based storms between Buffalo and Faith SD.

LONG:
We had enjoyed a few days of casual exploration in the Turtle Mountains and Peace Garden area, followed by exploring and photographing the North and South Units of Theodore Roosevelt National Park (TRNP) of North Dakota. The North Unit offers great hiking and few people…I highly recommend it for both geology and northern Great Plains landscapes!

All that was done while awaiting the next northern-stream shortwave trough, the system finally approached. This day offered the classic storm-intercept targeting conundrum of mid-June–stronger flow with weaker moisture up north, or vice versa farther S. Since “farther S” was New Mexico in this case, we stayed put, having found one of the few reasonably priced motel rooms in the region at one of the most inappropriately named towns on the Great Plains–Beach, ND. If you’re chasing in western North Dakota, be duly advised that rooms are scarce and expensive, and likely will remain so for the foreseeable future, because of the boom in fuel extraction from the deep Bakken Shale formation.

Fortuitously, the morning forecast scenario indicated storm initiation would occur near a slow-moving cold front and inverted trough over northwest SD and southwest ND–maybe even very close to us at TRNP. So…we cruised over to the South Unit of TRNP for some scenic hiking and driving in the morning, followed by lunch in Medora, and a grand plan to commence storm observing over the badlands of the South Unit in the mid-afternoon.

Towers already were erupting along overhead and to the S, when we were finishing a late lunch in Medora. We headed several miles E to the Painted Canyon area of TRNP and set up for a few DSLR time lapses of convection over the scenic North Dakota badlands. Here are some still shots from those, looking N and looking NE.

Those photos are part of several speed-adjustable time lapses I made from timed photos at those locales…be advised that these time lapses may load slowly if you’re on a low-bandwidth connection:

  1. Three time lapses looking N at convection forming along the boundary (time lapse 1, time lapse 2, and time lapse 3) looking N at the convection forming on the boundary, and
  2. My favorite, a longer time lapse I was able to build looking NE from essentially the same place.

Another clump of towers deepened marvelously with a mesonet site in the foreground. This told us the atmosphere was ready to do something special, the main question being, “What, exactly?”

Setting forth southeastward across southwestern North Dakota, we stopped occasionally to watch assorted towers build beautifully, ever deeper, ever grander across a verdant Northern Plains landscape. Several Cbs within a 75-mile radius offered themselves for targeting. This upwelling of atmospheric splendor to our NE, near New England (the town) tempted us, but the updraft and base on the N (left-inflow) side looked better than that on the near (right-inflow) flank.

This storm, and most others on the day, were either splitters or left-movers. Despite the decent deep-layer shear, small low-level hodographs kept storms from becoming too rightward-dominant, and therefore, from being long-lived cyclonic supercells.

Leaving that cell as it left us, we zigzagged farther SE toward Hettinger, to intercept another cell that was looking larger and more robust, visually and on Bismarck radar. We couldn’t quite reach our E option (US-12 near Bucyrus) before the storm did, so we let it cross the road with the abandoned Hettinger Equity grain elevator in the foreground. Being high-based, the storm traversed above a deep and slightly moisture-deprived boundary layer, producing a strong theta-e deficit in its immediate wake. Profuse hail up to an inch in diameter contributed to that localized cold pool, too.

Following the storm eastward, we saw more rainbows, finding the pot of gold not in a literal sense, but in the splendor of a convective Northern Plains sky, a treasure beyond measure, intangible and ephemeral yet perpetually memorable.

Being behind a storm, especially one that’s not terribly speedy and that likely won’t produce a tornado, often can be more photogenically rewarding than being in its way. Seldom was this more true than when we pulled beside a moist, rain- and hail-cooled field E of Hettinger for a tremendous view of the receding Cb brightening the northeastern sky with its convectively reflective brilliance. It was a great way to bid good-bye for the year to North Dakota–a state where they use spruce instead of cedar for wind rows (as seen in the last two shots), a state that had treated us very well convectively and otherwise over the preceding few days.

We dropped ESE obliquely across the South Dakota border on US-12 into Lemmon, noticing new development to our distant WSW, S of Buffalo. Without any decent, intervening north-south roads, and with the newer storms growing upscale and moving fairly rapidly, we headed S on SD-73. This also would take us closer to Belle Fourche, where we had made lodging reservations for the night, in anticipation of a meteorological down day spent at Devils Tower WY. We watched the very high-based, south end of a line of storms approach, laden with wispy tendrils of windblown precipitation, then dodged southward out of its way and into a twilight adventure driving to Belle Fourche.

We knew it would be an exasperating ride when we saw a sign, “ROAD CONSTRUCTION NEXT 47 MILES”. Although no actual, active construction was taking place, we ended up driving for about 25 of that 47 miles behind an 18-wheeler, on a rough, 1-2 lane dirt version of the state “highway” that featured sudden and unmarked lateral shifts in road position within its right of way. The truck drove off the road several times and back on again; so we couldn’t depend on its driver to guide us regarding upcoming jogs in the roadbed. We did, however, have to suck the dust, even while staying back a few hundred feet.

Needless to say, we got into our motel later than hoped, tired from the unexpectedly weary ride in, but thankful for one of the most purely pleasing convective days of the year.

Squall Line Way Up North

September 11, 2012 by · Comments Off on Squall Line Way Up North
Filed under: Summary 

St. John ND
10 Jun 12


SHORT: Blew off chasing in trees in MN or driving from ND-KS in one shot, intending to hang out in ND ’til the pattern returned favorable parameters to Dakotas. While en route to Int’l Peace Garden, intercepted photogenic, low-topped squall line and attendant arcus cloud over very green fields near St. John ND.

LONG:

The cold front from the previous day’s action was slated to shift into more forested land of central and northern Minnesota, within which we didn’t wish to chase. Strong to severe storms also were possible farther south, along and ahead of the front, in mode viewing-friendly areas of Iowa, NW Missouri and Kansas, but under weaker deep-layer shear.

Laundry beckoned, and so did a few days of R&R in the heretofore superficially explored state of North Dakota before the next substantial atmospheric perturbation brought severe potential to the northern Great Plains. After finishing the wash and brunch in Grafton, we charted a net WNW course on the township-range zigzag of eastern and northern North Dakota, aiming to grab a couple bucketfuls of rich, black soil from the old Lake Agassiz bed for my vegetable garden back home (check), visit Icelandic State Park (uncheck), see the Pembina Gorge (check), visit the International Peace Garden (check), and spend a night or two in the so-called Turtle Mountains (check).

Somewhat retracing the route we took the evening before, we encountered a fantastic layer of asperatus (a.k.a. “warm-advection clouds”) between Grafton and Cavalier. That was followed immediately by a rather featureless, messy band of elevated thunderstorms that timed badly for visiting the state park. Instead, we headed up to Walhalla and toured the misty, scuddy and decidedly green Pembina River Gorge by car.

Ascending that small canyon, which drains an escarpment separating the Plains from the Red River of the North valley, leads the driver to the marvelously open, flat and attractive countryside characteristic of most of the state NE of the Missouri River. Folks here seem to inherit their ancestors’ fastidious tidiness ethic. In towns, this means well-kept houses, gardens and lawns. In rural areas, we saw a distinct absence of junk cars, rusty appliances, neglected fencing, or haphazard accumulations of dilapidated mechanical rubbish strewn across weedy lawns of occupied homes–in other words, a refreshign difference from thousands of points of blight that are prevalent in the southern Plains countryside. Landscapes here were familiar from the day before, but the setting was different–scuddy, light rain on the back side of the elevated storm band, with broken blue sky to the west, and the cool, moist freshness of wet earth behind a summertime cold front. This trip already was a splendid pleasure, and soon would become more so.

Proceeding westward across the borderlands, we finally broke into sunshine west of Langdon–but not for long! Onboard radar showed a thin, curving arc of cold-core thunderstorms developing to the W, over the turtle Mountains. A low-topped squall line was forming–something that experience told me could be quite photogenic in such otherwise clean air and sky. It was.

Approaching the squall line from the SE (as it moved quickly eastward), we marveled at how shallow and low-topped the convection was–typical for a cold-core low in a low-CAPE, relatively low-tropopause setting–but still rather uncommon in my southern-latitude experiences. In fact, just a few miles ahead of the arcus cloud, sunshine still illuminated the moist and richly verdant fields adjoining the east side of the Turtle Mountains. This clearly was not any of the 60,000-foot-deep walls of deep-convective severity I’m accustomed to observing in a North Texas April.

Our viewpoint was just SE of St. John, only four miles S of Canada, and in a fine position to view the oncoming shelf cloud. We were able to frame the sweeping arcus above the gentle curve of a rural dirt road that nicely split the greenery. After that, we cruised into St. John and let the storms move over us, enduring a decent barrage of small hail and subsevere gusts.

Heading into the hills, we quickly left behind the weakening squall line and visited the International Peace Garden (highly recommended, no passport needed!). The storms had run off the visitors, so we nearly had the place all to ourselves in rain-cooled air with sunny, late-afternoon light. Afterward, and with no one behind us in the customs line, I had a long, very friendly conversation with a customs officer and USAF vet at the re-entry station (the park is directly astride the border, its driveway halfway between U.S. and Canadian customs). He gave us a good recommendation for lodging options beside beautiful Lake Metigoshe–at which we reserved two nights for R&R before the next chase-worthy, northern-Plains shortwave.

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