Central Oklahoma Tornado Outbreak

June 4, 2011 by · 1 Comment
Filed under: Summary 

El Reno/Piedmont, OK EF5 with Satellite Tornado
Dale, OK EF1 Tornado
24 May 11

SHORT: Intercepted tornadic supercells NW and E of OKC, the first with a violent tornado in progress, the second offering a scenic rope-out.

Welcome to a “High Risk” outlook and “Particularly Dangerous Situation” watch scenario that verified, weather-wise, exactly as such for central Oklahoma: in summary, three different violent (EF4+) tornadoes arose beneath three different supercells, with a fourth big tornado rated EF3 in northwestern Oklahoma (NWS Summary). Through both skill and luck, we witnessed what has been rated as the biggest and baddest tornado of the lot; yet we are respectfully mindful of the human toll that it took in spite of absolutely outstanding forecasts and warnings.

This almost classical Southern Plains tornado outbreak was so well-forecast and so thoroughly handled by SPC, local offices, local media and EMs, that I’ll eschew discussing meteorological details, offer a few prototypical 21Z (4 p.m.) mesoanalysis graphics that pretty much speak for themselves…

    MLCAPE and CINH | Effective Bulk Shear Magnitude | Effective Storm-relative Helicity | Observed ~850-500 mb Crossover | Effective SCP | Effective Sig. Tor. Parameter

…and now go straight to “the chase”. And what a “chase” it was, right into the area of maximized parameters you see on those linked mesoanalysis graphics, and at about that time.

Phase 1: Intercepting the Piedmont Supercell

After looking at some data at home, and at Ryan Jewell’s house, Jack Beven and I targeted the area near and just N of I-40 in west-central OK, mindful of the likely fast storm motions of the day and the need not to get too close, to soon, to developing storms. As we headed W on the big slab, the earliest cell of consequence erupted SW of Fairview, not too far from the previous day’s tornadic intercept. Indeed, though we didn’t target the storm due to incompatible relative motion vectors of it and us, it would produce a couple of tornadoes over and near Canton Lake.

Storms were forming closer to each other than I like, causing some interference and precip-ingestion problems. We waited just E of Watonga for the next supercell in a broken band of them, hoping to get a quick look while ultimately targeting the southern storm in the same grouping–the storm that would become the El Reno/Piedmont supercell. A quick jog back W to the fringes of Watonga, as the storm passed, revealed an outflow-dominant heap; so we flipped the vehicle back eastward, heading for Kingfisher and the next decision point.

As we got to Kingfisher, the big deliberation was: wait for the storm E of town on a good E-W road and risk that it would right-move to the morass of stoplights and traffic of Guthrie, or head S on US-81 to Okarche and risk munching some of the forward-flank hail along the way?

The radio station was blaring frantic TV simulcast reports of a “wedge” headed for El Reno. We vacillated for a couple of minutes, and I had my doubts; but Navigator Jack’s front-of-the-map calculations convinced me we could pull it off. We headed S toward Okarche into dreadfully darkening murk, intensifying rain, and ultimately, some hail, while hearing of the same “wedge” crossing I-40. Often such tornado descriptions are exaggerated; but I knew that, on this day, violent, large, and long-track tornadoes certainly could happen. Unknown to us, at the time, the tornado was sideswiping the El Reno Oklahoma Mesonet site with an 18-mb pressure drop and measured gusts to 151 mph–the strongest winds yet clocked by that network of weather stations.

Rounding the SE turn onto OK-3, we vectored an intercept position for any tornado coming NE out of El Reno. Blistering barrages of close CGs hammered the ground all around us, a fusillade so furious that I pulled my radar-delivering I-Phone out of the car jack, and we refrained from touching anything metal. A few hailstones clunked off the roof–none ultimately large enough to do damage, though we did see stones around two inches in diameter bounding off the road. The really huge and destructive hail was no more than a couple of miles to our S and SW; we had left Kingfisher in the nick of time to get around it!

We pulled S off OK-3 at Cimarron Road, about 5 WSW Piedmont, and drove S about a mile to a fine hilltop vantage. CG activity was backing off a lot, and we were (for now) out of precip. I could commence photography in relative safety. It was so stinking dark under that storm that I had to crank the ISO up to 1600 just to hand-hold shots with 1/25-1/60 sec shutter speed at f2-f4! At a time like this, I was so thankful for having invested in a top-end Canon DSLR and the L-series glass on the front. Using lesser equipment and especially with my old slide camera (which usually contained 100 ASA film), successful collection of the following shots would have been impossible.

And so we waited, looking along a lengthy cloud base from W-SW, footed by some dark murk well to our SW. We knew where the tornado was from the constant TV reports–buried in that murk–but couldn’t quite see it yet with our eyeballs. In fact, it was only after I took this 34-mm shot at 1630 CDT, then looked at the viewfinder presentation of it, that I finally could ascertain the outline of the tornado embedded in that murk to our SW (severely enhanced crop of same photo)! It was moving NE (toward us) at 40-50 mph. We had several minutes to hold position before having to decide whether to jog S on our paved, N-S road to get out of its way.

At first a multivortex containing a fat, tilted stovepipe, the tornado took on a wider configuration with a fat barrel and adjoining cone being two of the more persistent, larger tornadic vortices involved. Even at that distance, we began to make out wild cloud motions and rapid revolution of vortices around each other. The barrel temporarily vanished at 1632 CDT to reveal a fat stovepipe within an obviously significant, broader tornadic circulation.

Despite all the precip evident to the left (SW through SE) of the tornado cyclone, it maintained enough of a weak-echo moat around its immediate vicinity that our view kept getting better and better. The tornado also was growing larger as it got closer, closing in fast, not moving much right or left. This meant we likely would have to bail S sometime soon. But first, more observation and photography ensued as the tornado’s form fattened into a wide, dust-flinging barrel, then a bonafide wedge. The ambient wall cloud and occlusion-downdraft slot also became more apparent, contrast and visibility continually improving for the time being. We were impressed…very impressed. I told Jack, “Congratulations…your first violent wedge tornado.” Jack has been taking chase vacations to the Great Plains since the mid-1990s, often with the most deplorable luck in weather patterns. This was a new and potent experience for him.

As this grinding behemoth drew closer, I was supremely confident in its violence, while dearly hoping nobody was sheltering above ground inside its path. [I didn’t know it at the time, but this monster had killed several folks already around I-40.] The motions in and around the tornado were of a ferocity I’ve seen, in person or on video, only with tornadoes ultimately rated F4 or F5. As the sides of the condensation wedge appeared to froth and oscillate wildly, chunks of scud materialized at ground level in incomprehensible fractions of a second and raced diagonally up the and around the vortex at breakneck speed.

Given its slight rightward translation, I was reasonably confident the tornado would miss our location–but not my much. Any rightward turn, however, and we would be in grave peril with precious little time to spare. At 1635 CDT we turned S and drove a mile. As we pulled back onto Cimarron Road, a well-defined, horizontal accessory vortex formed on the near (NE) side just above ground, coiled around the N side, and rolled vertically up the rim of the tornado. This was a new experience for me, having seen the phenomenon only on videos of violent events such as Red Rock OK (26 April 1991), Golden Gate IL (2 Jun 1990) and Tuscaloosa AL (27 Apr 2011). Had I stayed at the previous location 30 more seconds, I could have photographed that too.

As good luck would have it, the tornado took a temporary NNE jog as we rolled S, maintaining safe distance. As bad luck would have it, torrential rainfall began wrapping around the SE and E sides of the mesocyclone, thoroughly dousing me in a veritable firehose of water after I jumped out and ran into photographic position. Barely able to stand in the roaring inflow, I hoped for just a shot or two before the camera would get too wet. It grew into a very wide, menacing wedge all the while, its collar cloud blasting around the mesocyclone with amazing speed. As the tornado moved to our WNW and NW, I clearly heard its roar–a throaty, primeval rumble somewhere in pitch between the closed-mouthed growl of an angry bear and the muffled booming of continual heavy-artillery fire.

This was one bad, bad, bad mother.

I reeled off one final good shot at 1638 CDT–capturing a satellite tornado that had just emerged from behind (W of) the big one, and was orbiting around its near-SSE side, throwing up a dust plume of its own. The satellite then turned NNE in front of the main event’s E side, and became lost in worsening contrast. The last and only other satellite tornado I saw was on 3 May 1999, near Chickasha.

Within seconds, the big tornado right-turned ENE again and got so wrapped in rain that we barely could see it anymore. It crossed OK-3 just W of Cimarron Road, and as we cautiously crept N back toward OK-3, crossed Cimarron road less than a mile to our N. Needless to say, I was glad it was moving away from us, while glancing overhead and around often for more satellite vortices. Furiously wrapping rain curtains parted just enough to reveal the E edge of the condensation vortex to our near-NNE, rightward of some power flashes. This was my last clean view of any part of the tornado, at 1640 CDT.

Meanwhile, the combination of inner-edge RFD plus southern-rim inflow to the tornado was severe at our location. The forward housing for my outside rear-view mirror launched itself like a rocket off my vehicle and sailed airborne for hundreds of feet out into a field to our NE, as the vehicle shook in the gusts. We were safe (barely), but also, not inclined to go any further N for a minute or two.

Even though the tornado did miss our initial photographic location, it wasn’t by much. I’m still glad we moved…under half a mile from the edge would have been unsafely close for a certifiably violent, still-expanding, precip-wrapping monster with proved tendency for satellite tornadoes and accessory vortices writhing around its rim.

Then hit a horrifying realization-–this tornado was headed generally toward the residence of my friend (and fellow storm observer) Rocky Rascovich, N of Piedmont. I tried to call and nobody answered; fortunately, it turned out they already were in shelter. His wife assured me later that it (barely) missed them and they were OK. It was the sort of tornado–fast-moving, expanding, wrapping in rain–that is the most dangerous and hardest to observe safely.

Later news of the deaths near El Reno and Piedmont humbly counteracted any sense of gratification I had that evening at getting the good-contrast, big-wedge shots about which I had dreamed since childhood. This is the ethical paradox and dichotomy of conscience for any storm photographer.

Phase 2: Intercepting the Dale Supercell

Cruising along the mostly empty Kilpatrick Turnpike (around N OKC) we briefly debated whether to go up I-35 and meet the storm at Guthrie; but its deep precip-wrapping and messy radar appearance convinced us to jump SE for newer storms headed out of the Chickasha area. Early reports of tornadoes from those sealed the deal.

Jack and I tried to get S of Norman, but were stopped by a traffic jam on I-35 in town (flipped car unrelated to tornadoes) and couldn’t get to Goldsby readily to observe that event. Had the Goldsby tornado turned slightly more leftward and gone up I-35, it could have plowed through hundreds of stopped vehicles up and down the highway!

Instead we waited a short time near the North Base for what was left of the Newcastle storm (by then, nearly nothing), then backtracked some back roads to I-240/40. Along the way I spoke to Elke; they headed to my neighbor’s underground shelter as the Goldsby event headed for Norman. In northern Norman and along I-240/40, Jack and I encountered occasional marginal-severe hail and falling small debris (insulation, leaves, small twigs) that had been launched by the Goldsby tornado into the supercell’s far-forward flank.

The Goldsby storm also had been slammed by a left-mover, temporarily disrupting its organization, dousing the once-violent tornado before it could grind through some part of Norman. I was glad of this, as it spared a lot of destruction in the town in which I reside!

As the supercell reorganized, we vectored the new mesocyclone to cross W of Shawnee near Dale, in a mostly hilly and forested area. Fortunately I knew of a large, flat, open field just S of the I-40/OK-102 (Dale) exit, from which I had photographed the OKC ice-machine storm of 16 May 2010. We headed there and waited for the reorganizing mesocyclone region from the approaching supercell to come into view.

From the murk, at 1830 CDT, a low-hanging, conical cloud form appeared to our W, hard to see at first beyond the red farmhouse in the last shot (super-enhanced crop). This feature had good temporal continuity with what would emerge more visibly by 1832 (super-enhanced crop)–the Stella-Dale tornado, as a tilted cone beneath a deeply clear-slotted wall cloud. We weren’t totally sure yet by our eyes, even then (given the hazy conditions); but by 1833, it was obvious that a tapered cone tornado with debris fan (super-enhanced) was moving in a general ENE direction to our WNW, very close to I-40.

As the tornado grew closer, its form gradually became sharper and also more sinuous, contorting spectacularly into a long curved tube. I was so mesmerized by the wondrously serpentine evolution of the visible vortex that I didn’t think to slap on the zoom lens until the tornado roped out at 1836 CDT. What was left of the mesocyclone next moved N of us, got undercut by rain and outflow, and vanished into the murk N of I-40.

We cruised E on I-40 to look at two more supercells near Prague and Okemah; but their structure was more amorphous, with little evidence of robust low-level rotation by that time. Along the way back, we noticed mostly minor (Ef0-1) damage alongside I-40 2.5 W of the Dale exit, where the tornado crossed. The wreckage of the big rig, whose trailer got blown to pieces, still was being hitched up to a towing vehicle.

By the time we got back to Norman, we were thankful that my home (and those of others in Norman) was spared, and that we got a high-contrast view of a violent wedge…but also, once again saddened for the casualty toll from yet another deadly tornado day among far too many this year. We met up with the Fogel crew for dinner (they had far worse luck than we with tornado observing on this day), as well as Elke and my kids, swapping stories of a great chase (us), a frustrating one (DF’s crew), and another Norman scare (my family). Aside from a dollop of mental exhaustion, my other impression was: “I’m about ready for the High Plains!”

A Real Stretch

June 1, 2011 by · Comments Off on A Real Stretch
Filed under: Summary 

Okeene and Karns, OK
23 May 11

SHORT: Observed small tornado W of Okeene OK and nontornadic supercell E of Greenfield OK.


This “day before the day” heralded the beginning of the long-advertised “undercutting Pacific jet”, and impingement of a strong, broadly cyclonically curved upper wind max over the southwestern CONUS as a 500-mb cyclone closed over the Pacific NW. I much prefer patterns like this for observable supercells than closed, stationary to retreating northern-Plains lows like we had just seen.

A strongly difluent upper height pattern spread over the southern High Plains late in the afternoon with subtle height falls occurring across much of the region. The presence of a dryline that was
1. Beneath those height falls and
2. Bounding the west rim of a rich moist sector (at least over the TX portion)
…was a high-confidence scenario, the specifics being maxima in low-level lift versus strength of capping into evening.

Accordingly, Jack Beven and I, in caravan with DF’s “Dude, Three Chicks and a Dog” chase team, headed W on I-40 to await storm initiation along the dryline in a strongly heated and increasingly moist air mass.

Along with Howie Bluestein, Dan Dawson, Jeff Snyder and other scientists and students accompanying OU mobile radars, we waited and shopped at the Cherokee tribal store on I-40 near Calumet, until echoes appeared to our SW, W and NW. We parted with the OU crews, briefly stopped to watch some high-based junk SW of Watonga, then targeted the much more healthy Fairview/Okeene storm.

In fact, the storms SW of Watonga were everything but photogenic; and we still were in transit northward Okeene when we caught a view of a suspicious lowering under the emerging base W of Okeene. In a rare event for me, my first photos on this day therefore were of a tornado!

By 1618 CDT, when we pulled over along a section road 3 S Okeene, the lowering had become a well-defined funnel cloud about 5 NW of us or ~4 W Okeene. It was tilted nearly horizontally (wide-angle with foreground storm structure), and already tornadic based in dust-whirl reports by closer observers. Time was 1618 CDT. The newer updraft base almost overhead seemed to be the next candidate for a mesocyclone formation/occlusion process; but it actually moved N and got absorbed into the forward flank, vanishing in the process.

Meanwhile, we witnessed, photographed and reported the 6-minute tornado from the same vantage as a debris cloud became more and more apparent (unenhanced and super-enhanced photo). Shortly before the tornado dissipated, the debris cloud got displaced astonishingly far S of where the condensation funnel met the cloud base. Clearly the stretching term of the vorticity equation was at play here.

We stayed with the storm for about 45 more minutes just E of Okeene as another small thunderstorm formed to its S, moved over us with frog-strangling rain and closely slamming CGs, then merged into the main updraft region. This pathetic state of affairs left the supercell demolished as a discrete entity. What was left merged into a massive multicellular morass extending some 70 miles E-W across the area. Now what?

Onboard radar feeds tempted us intensely with displays of a solitary supercell about 75 miles to our S near Gotebo, and there was plenty of daylight to head down there and spend some quality time with that storm before dark. Off we went, photographing a smaller cell to our SSW over Watonga. (which would become the supercell E of Greenfield) and later a distant presentation of the convective mass we had left.

That Watonga storm looked rather innocuous as we passed under its early updraft base in and S of town. However, by the time we reached Greenfield and around to the S side, the convection grew explosively into a full-blown young supercell with bright, hard-looking updraft towers boiling up the back side. The upward eruption of the convection easily was visible in real-time via our eyeballs, as was the onset of helical turning in the midlevels, white turrets and cauliflower tops rocketing skyward and veering rightward like daddy likes to see.

We didn’t intercept this storm; it intercepted us. The supercell blossomed right besides us on the way S, in an environment not seeming too different from more mature supercell to which we had been aimed; so we diverted from plan, maneuvering the backroads NE of Karns into the near-inflow region of the Greenfield storm instead. Its first mesocyclonic occlusion attempt happened just to our NNW with a well-defined, if elongated, wall cloud that rotated only slowly. Rotation tightened considerably after the mesocyclone became deeply occluded, slotted and nearly cut-off from the rest of the storm, having been kicked way back out the NW side of the storm. Alas, loss of buoyancy overcame stretching; and the circulation perished.

After that, several areas of weak-moderate rotation materialized along an increasingly elongated cyclonic-shear and convergence zone; but the supercell itself was getting weaker and more strung out. We left it and headed S on US-81 through El Reno, once again headed for the initially intended supercell still a little over an hour S of us; but that storm died before we got past Tuttle. Little did Jack and I realize we were crossing the path that a certifiably violent and deadly wedge tornado would take the following day.

We enjoyed seeing Jim Leonard in the field as well as the aforementioned OU folks, and had a fine dinner in Norman with Matt Crowther, Betsy Abrams, Greg Stumpf, and my beautiful bride Elke, who couldn’t chase on this day. It was a fine and fitting end of the “day before the day” setup. What a wild, frightening, intense, and historic day the “day after the day before the day” would turn out to be…