Second Dose of Beautiful Outflow Dominance
Limon to Sheridan Lake and Lamar CO
17 June 11
SHORT: Intercepted two supercells that quickly became outflow-dominant in east-central CO. Picturesque structure. Nighttime lighting, mammatus and moonrise show near Lamar CO.
LONG: Starting at the laundromat in Yuma, we headed S at midday toward a forecast initiation area near the Palmer Divide, which by the time we hot the open plains S of town, already bubbled with tall convective towers. As in the previous day, I was concerned that storms would go too soon and create a big outflow surge; but instead they percolated for some time, struggling to organize as we approached LIC. There, we sat under the NE edge of a high-based, fuzzy, virga-spraying line of cells, none particularly impressive for about an hour.
Finally, as so often happens on these highest of the High Plains, a few distinct updraft bases materialized from the mush, one of more of which I guessed would evolve into a supercell, given both the favorable deep-layer shear and increasing low-level moisture content with time. When some of the virga started to reach ground as rain in LIC, we zipped several miles S of town then W a mile on a dead-end dirt road to watch the action unfold, while remaining in at least marginal phone-data coverage of LIC’s cellular towers. Turns out we didn’t need the data…as often is true out there, the eyes have it.
Two supercells developed essentially in sync — one to our somewhat distant W beyond Simla, the other to our NW between Matheson and LIC.
The closer storm evolved fast, and in fascinating ways. The initially broad, high updraft base in the last photo lowered somewhat, with a broad, ragged cigar of scud materializing beneath as the updraft began to process rain-cooled air from the neighboring parts of the forward-flank core. Notice, in the last photo, the lower-middle part of the scud bank seems to be rising off the ground. In fact, it not only was rising, but weakly rotating–before the broader scud stogie ever attached to the parent storm’s cloud base: a “scudnado” indeed! The scud mass kept growing and rising, becoming part of the storm’s updraft base and lowering it tremendously. This is a classic example of a storm modifying its own thermodynamic environment to ratchet down its own LCL!
Meanwhile, we saw intermittent chunks of ground-based scud, rising and slowly rotating. Nothing appeared too threatening from the standpoint of developing a real tornado, but it certainly kept my attention, in case the circulation ever started to tighten up to ominous levels. Some of them certainly had that look (zoom lens and enhanced digital zoom). I was pleasantly surprised and glad to see that nobody called these in as tornadoes, knowing that a lot of chasers were roaming about the area (based on Spotter Network icons). Another example a few moments later: (zoom lens and enhanced digital zoom).
The first supercell moved ENE over the LIC to our N, and gusted out. That turned our attention to the second (western or “Simla”) storm, which had sported intermittent, mostly non-rotating and ragged lowerings so far. A large, weakly rotating and precip-wrapping wall cloud developed as the storm drew closer, thanks to a a big mass of rain-cooled air entrained into the main updraft region. The supercell turned hard right, heading ESE and bearing the forward-flank core on course for the location where we comfortably had parked for about an hour. Time to head S again…
N of Punkin Center, we stopped to the updraft’s E again, this time for a short spell to photograph some beautiful clean-air storm structure. The supercell grew ever more outflow-dominant by the minute and accelerated its forward speed, so we couldn’t stay long. One more shot of the striking form of the storm, a marvelously textured swirl of gray shades and turquoise looming across the western sky, and it was time to bail over toward Aroya to open up some room between the storm and us. Along the way, its gust front briefly passed to the NE and to the N.
Approaching Aroya, we remembered a beautiful, old, abandoned schoolhouse we had seen on another chase nine years ago, having wished someday to photograph it before an approaching storm. This was our chance! The result is one of my favorite Great Plains scenery shots of the year so far.
Near Wild Horse, the supercell tried hard to enlarge a surface-based updraft, and appeared to succeed. The result was another spectacular display of texture and shading. Yes, that lowering at the inflow-outflow interface was rotating–slowly, but helically, giving me some concern for a brief tornadic spin-up. This one (zoom, and enhanced zoom of a zoom) compelled me to call, but thanks to being in one of the many tens of thousands of square miles of the Plains that constitutes AT&T’s 3% of America not served, I had no signal.
Fortunately, that feature quickly dissolved under relentless assault from cold outflow. Shortly after those shots, YF Umscheid motored up the dirt road toward us from a vantage closer to the feature, without reporting anything of consequence. We stayed ahead of the storm as it surfed outflow, driving E to Cheyenne Wells then S to Sheridan Lake. Between those burgs, we stopped to photograph the increasingly high, tiered, arcus-like eastern part of the base and a pretty array of sunset tones on the W side.
The storm now being a windbag and dust-bomb, we left it to get some lodging in LAA, setting us up for a long-desired revisit of Bent’s Fort and perhaps another chase opportunity the next afternoon off high terrain near and S of the Palmer. We found a nice, locally operated motel, then headed just SW of town to watch a short-lived, probably elevated supercell approach in the fading twilight. Elke was getting tired, so we went back to the motel, as the storm peppered town with abundant hail up to 1 inch in diameter (definitely smaller than the supposed “golfball hail” in the local storm reports).
A good lightning show beneath and on the back edge of the storm sent me back S of town again onto a different side road, this time to photograph the mammatus-festooned electrical show from the rear. As crickets and frogs sung loudly from every point of the compass, that amazing moist-earth smell refreshing my spirits amidst cool outflow air, the lace-lightning display continued with the storm’s eastward retreat. As a bonus wonderment, to cap a fine storm day, an orange moon rose beneath and then behind the distant updraft base. In the last shot, above the flanking line, you can see the anvil edge illuminated by the moonlight, in addition to the lighting by lightning within the storm.
After a long and satisfying chase day, we slept very soundly that night!
For your enjoyment, and as a reward for patiently reading this far, I’ve thrown together a couple of coarse animations from tripodded still-camera images shot that night: the first of the retreating storm with lace lightning, and the second of the wide-angle moonrise scene.
High Plains Lightning Festival
Colorado-Nebraska Border Region
13 June 11
SHORT: Began in BFF. Waited in SNY. Avoided outflow-surfing CO/NEb border storms to intercept supercell near AKO, saw probably non-tornadic dust whirls with storm merger there. Fantastic twilight lightning display from elevated storms along border S of IBM.
LONG:
Elke and I started the day in BFF, targeting the general area of the CO/NEb border SE of there. I wasn’t particularly jazzed by the weak lower-tropospheric winds in the forecast, figuring outflow and/or storm splits would be a problem. Still, it’s the high plains in early June with adequate moisture, upslope flow and at least marginal shear. The answer? Be there.
We waited a good, long time at a hilltop outside SNY, just NW of a dryline that eventually would fire up a tornadic HP supercell in the horrible road network and terrain of the Sandhills. We saw those towers to the distant NE, but chose not to pursue given the great difficulties involved with storm intercepts in those parts.
Meanwhile, we listened to meadowlarks and, on radar displays, watched chaser icons on SpotterNetwork zigzag back and forth across the area in impatience as the lack of focused action. Fuzzy storms began to fire between the Laramie Range and Cheyenne Ridge, which was no surprise; their distant bases were so high we could see them from SNY. I wasn’t impressed. Red dots converged on I-80 and headed W. We sat, waiting and hoping instead for dryline development to access richer moisture to our SE and E.
Finally, off to the distant SW, two storms erupted near and N of the Palmer Divide in Colorado. This was near the very southern fringes of our forecast area; but as nothing much was happening with the dryline nearby, and the storms were reachable, we decided to go have a look. Along the way SW, through the convoluted maze of roads that is Sterling CO, the southeast storm attracted quite a few chaser icons. The NW storm didn’t, was closer, and was in a similar environment; so we headed toward AKO to intercept it.
Alas, along the way, the SE storm calved off a big left-mover and died! Moreover, the left mover shot toward the inflow region of our target storm like a torpedo hell-bent on mutually assured destruction of both storms. Briefly, we got a view of the NW supercell’s mesocyclone area to our WSW before the left-mover’s core arrived; and it looked like a somewhat higher-based version of a North Texas HP “Stormzilla”. This meant big hail; so it was imperative to get S fast.
Yet there loomed the left-mover over the road to our S, likely bearing ice bombs also. It got there as we did, just S of AKO. The two storms started to merge overhead, and in the tiny gap between their cores, two strongly rotating dust whirls appeared less than a mile to our W, about 3 minutes apart. [I was driving and driving hard, so...no photos!]
Though a narrow, ribbon-shaped updraft had formed overhead at the merger location, we could see no obvious rotation in it. I attributed the whirls to gustnado-like vortices being stretched where the two gust fronts met. We maintained an equatorward bearing, encountering only marginal severe hail at best (to our relief).
Arriving just S of the combined storms, which indeed were killing each other, we photographed the dying supercell across rain-drenched corn stubble S of AKO. It was good to see Steve Hodanish and to swap Hodo stories with a co-worker of his, and also, to talk with a few other friendly storm observers whom I hadn’t met before. Yet we were essentially stormless, parting ways and headed back toward our various bases for the night. All that was left, for now, was outflow spinning a windmill under a dark and stormy high plains skyscape.
We headed toward lodging in the Nebraska Panhandle, soaking in the sights of Pawnee National Grasslands in anticipation of spending a couple of upcoming non-chase days of roaming around some of our favorite haunts around the Black Hills, not counting on any more atmospheric excitement. As good fortune sometimes plays on previously under-performing storm days, the night brought about an unexpected–and most welcome–show of splendor that made our night!
A short line of elevated and high-based thunderstorms erupted over the WY-NEb border region atop the outflow pool from all the late-afternoon activity, and moved SE across the southwestern Panhandle and across the Cheyenne Ridge. Evening storms like this in the High Plains can spark profusely, and these absolutely did! We found a vantage just over the CO/NEb border S of IBM (Kimball, not the company) and began shooting away at the approaching spectacle. Assorted forked and in-cloud displays slashed across the fading twilight, their reports blasting resonantly across the wide-open landscape. Soon, some cloud-to-air discharges flickered forth, followed by yet more (and closer) sky-splitting CG action. Wow…what a show!
The lightning was getting too close, though; so we drove through the translucent core of the thunderstorm line a short distance into IBM, crossing a few miles of small hail (with almost no rain!) along the way. I’ll never forget the sight of countless thousands of little white hail balls in the high beams–cascading dots of brightness, the only form of light shining back at me along that dark High Plains highway.
After securing a motel room near the edge of town (like we like to do), we noticed the sparkling display still underway to our SE, and headed back out past the E edge of town for a little crawler-lightning show in the trailing precip region. And with a few more flashes to light up the midnight hour across the western Nebraska prairie, bedtime drew nigh, our storm-hungry palates duly satiated. I had very few lightning photos to show for 2011 until this night, when the heavens unloaded electrical gifts one after another in a most dazzling and appreciated fashion.
Oklahoma City HP Ice Machine
Oklahoma City to Ada, OK (16 May 10)
SHORT: Observed fast-moving HP supercell from eastern Oklahoma City to between Seminole and Ada, then let storm pass by into southeastern OK.
LONG:
In the couple of prior days, I had considered some potential for severe storms across the region — mainly between I-40 and I-20 where it appeared the strongest midlevel winds would occur in a belt south of a mid-upper level trough over the central plains. The problems seemed to be lack of coherent initiative foci, rather weak moisture (resulting from the air mass to our S over TX being scoured by huge convective complexes), and weak near-surface winds that would keep hodographs small.
With far more negatives than positives apparent, I (along with many other storm observers) didn’t pay a great deal of attention on the day of the event. In fact, I was eating late lunch in Moore with Elke, Rich Thompson, Jack Beven and Jim Leonard — all experienced chasers of many decades in aggregate — when a supercell materialized out of a clump of convection NW of us near Okarche. The hook echo on the TV display and on our phones definitely got our attention.
Yes, a quick look at the surface map showed weak, mainly SW winds at the surface, though there was a sharply defined, E-W boundary extending N-NW of OKC. Turn the entire setup (including NW-SE storm motion) leftward 30-45 degrees, and you’ve got an east-moving storm with light SE winds. That’s not bad. Surface dew points in the inflow region were on the low side at about 62 degrees F, but the presence of the storm told us that was more than sufficient! Bellies full, we all scattered to our respective domiciles to get camera gear, and ended up separately observing the supercell.
Elke and I headed N from eastern Norman intending to photograph the storm coming over downtown, but its gradually accelerating motion precluded that. Instead, we first got a good look at it to our NW near the junction of I-240 and Sunnylane, with lots of buildings, wires and such contaminating the foreground. It was moving SE at 35 mph and accelerating further, and we had to head E on I-240/40 to stay ahead, if we wanted any hope at a good view without getting demolished by the baseball to softball size hail that was pounding northern and eastern Oklahoma City. We also drove right past the intersection of Choctaw Road and I-40, where a violent tornado had destroyed a truck stop and caused casualties the previous Monday. No time to look…we had to keep going!
Along the way there, we were listening to the radio simulcast of KFOR-TV, where Mike Morgan was saying, “We’re under attack at the KFOR studios! Skylights are breaking, baseball hail falling right here! We are under attack! This storm is taking no prisoners.” Now, Mike is not exactly the dignified, stoic gentleman of 1960s/70s television, seriously delivering the dire news of impending meteorological doom. He is no Harold Taft by any measure, and never could be. That said, while his penchant for over-exuberance and occasional exaggeration is well-known, he wasn’t too far from the truth this time.
Meanwhile, eastward we forged in search of a vantage. In this part of central Oklahoma, the Eastern Crosstimbers arboreal province, it’s very difficult to get a good view of a storm, with the trees, hills, and buildings rampant. We pulled off I-40 several times in futility, but finally and briefly found a very nice look about 2 SSW of Dale, on OK-102. To our NW, the north part of the storm (where the mesocyclone was) sported a beautiful tail (stinger) cloud, with a cream/reddish wall cloud rotating weakly. It was obviously being undercut by outflow and in no danger of a tornado. Given all the tornadic destruction of six days before, this was a good thing; because folks in these parts are hypersensitive to big, mean-looking storms.
I managed to photograph the south part of the supercell (looking W) before the storm closed in. We zigzagged S and E to Seminole, edging the hail core (nothing damaging), and driving past more of the previous week’s tornado destruction along Highway 9. Not wanting to get munched by a hail core in Seminole, we charged S to 12 N of Ada, and let the outflow-dominant storm race across the road right behind us.
All in all, this was an unexpectedly rewarding afternoon for a couple of storm observers who hadn’t counted on seeing much. Unfortunately, Oklahoma City took an epic beating from the hailstorm, the costs of which will run into the tens (maybe hundreds) of millions, not counting the insurance premiums that are sure to skyrocket even more. Since we stayed (mostly) ahead of the storm, I don’t have any hail photos, but the brief episode of photogenic structure near Dale was well worth the effort.