Tushka Culmination
Southeastern Oklahoma, 14 April 11
SHORT: 3 supercells intercepted in SE OK, likely end of Tushka tornado witnessed after navigating damage.
LONG:
Ryan Jewell, Jaret Rogers and I left Norman after working the day shift, headed SE toward Ada to get ahead of the supercell that already had crossed I-35 near Davis. Vigorous convection had gone up just E of Norman too. We eschewed that option completely while E of Lexington, given that it was heading into an environment of weaker shear and buoyancy than farther S, and had messy radar structures and mergers happening by then.
Alas, so did the old Arbuckles storm, by the time we saw its inflow region, looking NW from near Stonewall. We had beaten the hail core through Ada by just a few minutes, and took the time to marvel at the turquoise color of the wrapping precip and the long tail cloud. Motion into the mesocyclone region was really fast, inflow screaming from the SE; but mergers with other cells to its S had rendered the supercell, still with an intense mesocyclone, a garishly greenish HP stormzilla.
Two more supercells beckoned to our SW, the first headed for the area between Tupelo and Clarita, and easy to intercept. The storm had a great reflectivity hook, and was TOR-warned; but the low-level velocity structure didn’t look particularly vigorous on radar. Visually, as seen from Clarita (looking WNW), the convective structure was very robust, the base far less precip-infested than the Ada/Stonewall storm. Still, it had a long, scuddy rear-flank gust front, with similar scud drifting about under the putative mesocyclone region. A broad, ragged, very low-hanging, but only weakly rotating wall cloud formed, then fell apart. Not too impressed, we didn’t longer longer, and made haste down OK-48 through Coleman, to OK-22 and westward after the southernmost (anchor) storm near Tishomingo.
We arrived within sight of the storm’s base just a tad late to see the Tishomingo tornado, having this NW-looking view of two wall-cloud regions as the storm moved close to Milburn. The nearer (dark) one fell mercy to the rear-flank downdraft wrapping around the more distant, northern, older, and occluded meso near Milburn (brightened by clear-slot light in this later shot). Here we met and chatted for a spell with Ashton, who later ended up in the damage track of the Tushka tornado very near us as well.
The near (southern) meso thus undercut, we headed N to get a closer look at the circulation near Milburn, but it too was weakening. A wrong turn in Milburn led us to some knobby and often partly broken hail up to 2-1/4 inches in diameter, which we photographed before heading the correct way out of town. We zigzagged from Milburn to Coleman, getting close to the storm’s back edge of the re-intensifying supercell’s hook region. We considered an unmarked road to the east, through Boggy Depot, but rejected it as unsafe, given its unsavory look on the road map, and its precarious position slightly N of astern with respect to the new mesocyclone area. Take that road, we knew, and huge hail wrapping around the backside of a hook echo would be a sure fate.
Instead we busted S back to OK-22 and E to US-75, then N past Caney, arriving to see a mesocyclone with dark, amorphous murk beneath moving past the road in the distance.
Not yet knowing that a tornado was somewhere within that murk, we proceeded NNE up US-75 into Tushka, unaware at first of the intensity of the damage until we had gotten irreversibly into it, embedded in a stream of slow-moving traffic. Broken and uprooted trees appeared on both sides of the big roadway, becoming more numerous in the first mile or two, along with assorted sheet metal, pieces of wood, broken road signs and other variegated flotsam. The blended scent of shredded vegetation, split green wood and rain deeply saturated the air, a unique aggregate aroma I’ve experienced only amid fresh tornado damage.
Right after we drove several feet safely beneath some low-hanging power lines, an adjoining tractor-trailer rig hit them…and kept going full speed! It busted at least three power lines, yanked down a power pole that still had been standing, and may have dragged another already downed pole a short distance. I suspect one of my most abiding memories of this chase will be the furious, staccato “THWAP THWAP THWAP” noises as the cables snapped just behind and next to us. We were aghast that the driver would just plow right through low-hanging power cables, snap them mercilessly, and keep on truckin! I guess he had places to be.
Even within a few minutes after the tornado, plenty of police and other first-responders already were arriving or there. We saw several vehicles flipped asunder, as we navigated around whole trees and large debris on the road; and every overturned vehicle I could see either had no one inside, or at least one person standing next to it. Under those circumstances, and mired the plodding traffic, the best move was to get through the mess safely and expeditiously as possible, and get out of the way of those who needed to be there. It reminded me eerily of coming into the damage swath along I-44 right behind the (also rain-wrapped) Catoosa F4 of 24 April 93. As we entered Atoka, the damage lightened; though we could see more off to the east.
With several miles of damage along the highway, the tornado obviously was fairly wide, even if not exceptionally violent, and took a very oblique path with respect to the road. Even in the deepening twilight, now quite dim under all that storm-cloud cover, we still could see rapid scud motions from left to right above the road (NNE of us), wrapping back around an unseen mesocirculation center to our NE. From Ryan’s I-Phone radar, we figured the mesocyclone (and temporarily, the storm as a whole) had taken a left hook toward the NE, with a new occlusion forming farther downshear. As it turns out, Rich confirmed this for us while we were still in the damage, calling him to report it just in case none of the other hundreds of people had. He also let us know that the mesocyclone was narrowing and perhaps even crossing back over the road as it veered leftward.
Lo and behold, right then we saw a power flash to our NNE, slightly leftward of the road, near Stringtown. Within a minute or two, a ghostly, dim but still very apparent cloud cylinder emerged from the wrapping precip, right in the direction of that power flash. The cloud column, whose bottom was obscured by a terrain ridge, contorted and gyrated wildly, with a ragged coil or helix of scud pulling around the near side shortly before it fell apart. The previous volume scan showed the narrowing couplet in that spot, and the next had it dissipated.
I am now convinced that was the deeply-occluded demise of the Tushka tornado near Stringtown, kicking back out of the rear of the precip-filled area (as I’ve seen a few times before). This is based on Rich’s real-time descriptions of the meso occlusion process on radar, my own post-event radar review, the path/timing of the old occlusion relative to our position N of Atoka, what has been documented of the path so far, and of course that wildly morphing cloud cylinder near where we just had seen a power flash. All things considered, not very satisfying. It’s ironic that the best view of the tornado (Gabe’s, while in some gigantic hail) was from the WNW–the angle we chose not to approach when we were just behind the storm in Coleman.
After the meso died, it was dark; and we found ourselves in a quandary. Dense cores kept crossing US-69 to the NNE, the NW route to Ada (US-75/OK-3) was blocked by a supercell, another supercell was back near Wapanucka headed for Atoka, and miles of tornado damage lined US-75/69 to our S. Solution? Eat. Also, sit down and plan some escape strategy.
At the Subway in north Atoka (an undamaged area), we heard of a triage setup elsewhere in town–the first sign that some casualties had happened. This was bad news indeed. [We didn’t hear of the two fatalities (elderly sisters) until after returning to Norman.] The next TOR polygon for the supercell to our W included Atoka; so the already frazzled employees started locking up to take shelter.
We finished eating out in the vehicle, as the supercell to our W weakened and passed just to the NW. The door out of the area now opened, we then headed home, listening to a combination of Metallica, Slayer, Iron Maiden and Pantera on Ryan’s phone to just wind down a little.
Meteorologically, our forecasting and pre-storm conceptualization was reasonably good. The only part that didn’t work out as well as I like was the large number of left splits and close-proximity cells that made storm modes messier than the orthogonal deep -shear vectors would indicate. Smaller early hodographs with some negative SRH probably contributed to that, along with a nearly simultaneous dispersion of CINH all up and down the area just E of the dryline, from the Red River to the KS border.
The US-412 Supercell
Enid/Garber OK
8 Apr 11
SHORT: Modest, yet enjoyable supercell observed east of Enid that developed in the warm sector (not on the dryline).
LONG:
The initial thinking from prior days, and early on this one, was that a dryline storm could fire somewhere over western OK in a zone of intense heating and mixing that would overcome strong EML-based capping, and move eastward into more moist air for a short time amidst an ambient kinematic profile most definitely suitable for storm-scale rotation. Instead, we ended up with one warm-sector supercell out of several! Here’s how…
A persistent zone of northward-moving, gradually deepening cumuli, corresponding to a zone of intense heating and mixing east of the dryline, formed during early-mid afternoon over NW TX near Vernon, and also, in an area of weak surface wind-shift and mass convergence as evident in both plotted charts and objective analyses. This immediately caught our attention (Corey M, Rich T and I); and we began to ponder this as a potential storm genesis source. The later it went, the farther N it would go; as the combined surface and satellite feature was moving N across I-40 and into the Kingfisher area by the time we left. After Rich picked up his son from school; we all met at Battlestar Norman and departed for El Reno via the Highway 9/turnpike bypass, intending to head N on US-81 from El Reno.
While near the former Kelvin’s Corner, we spotted turkey towers with glaciation to the NW, a good sign of deep ascent that encouraged us onward. VIS imagery showed a boomerang-shaped field of deeply enhanced Cu, much of which we couldn’t see visually from a distance because of smoke-related boundary-layer haze. The inflection point of this boomerang was moving N from the Kingfisher area; so we headed that way. That’s where the first echo–the eventual Enid storm–erupted while we were approaching Kingfisher.
We cruised up to Hennessey as the nascent supercell grew, towers rolling up its near (SW) flank and backshearing. The storm lost some organization on radar during an initial storm split; but its updraft towers till looked robust visually. In accordance with that encouraging sign, the right-split recovered nicely from the initial body-blow as we maneuvered E on OK-51 and N on OK-74 toward Covington.
Our initial views of the underside from SW of Covington (no photos…stupidly, I left the camera in the back of Rich’s vehicle while we were driving) revealed a high, somewhat disorganized base. As we approached from the S, the eastern portion of the updraft region began re-ingesting a partial mix of rain-cooled air. Huge chunks of scud formed and rose, appending themselves together into a tall, ragged wall cloud that rotated slowly, assuming a triangular shape for a short time. At one point, the point of the triangle lowered about 4/5 to the ground from a very high ambient cloud base; but rotation was slow at best, and no dust or debris could be spotted beneath. This seemed to be the “almost a tornado” phase some chasers described.
As we reached 412 and turned E, the storm was in its best-organized phase–peak midlevel rotation in SRM displays and that ragged, occasionally low-hanging and pointed wall cloud with obvious cyclonic shear. The meso wasn’t strong enough to pull a great deal of precip around yet. As we continued E on 412 and got abeam of the circulation, a lot of the scud evaporated, as if the wall cloud were disrobing to reveal a peculiar, tilted but mostly horizontal cloud vortex. This feature narrowed into a skinny, nearly horizontal funnel, somewhat bent, and way above the ground. We didn’t deem this an imminent tornado threat.
By the time we pulled over at an optimum vantage, and I got out the camera, the laminar, horizontal, funnel-like feature to our N had vanished; and the ragged wall cloud was eroding away to reveal the more ambient, high base again. At this stage, the structure reminded me a bit of the 22 May 7 supercell near St. Peter, KS, but of course, without the tornado! Storm motion slowed down; and we were able to maintain a leisurely pace east on US-412 with a couple of long-lasting stops to observe the supercell’s high but well-structured underside to our N.
The storm attempted a couple of occlusions, including this one with a well-defined downdraft slot and precip cascade, while surface-based inflow still was screaming from the S and buffeting us reasonably well. Soon, however, the inflow calmed a bit, and the storm took on a more laminar, elevated appearance as it approached I-35 (shot looking NNE with CG from the vault region).
As the storm continued to weaken, we bid it a fond farewell, and headed S on I-35 toward home.
This was a fine first chase of the season, a good opportunity to work out some kinks, test new equipment, and re-learn needed lessons (i.e., “Self, you forgetful doofus, keep the damn camera in reach while someone else is driving!”). It was great to get out on the Plains again and watch a supercell–a cathartic release from the psychological imprisonment of a long, cold winter. Even though we are mired in deep drought here in central OK, we bear hopes for at least a few more photogenic supercells within reasonable driving distance the remainder of the season, as prospects for the big events already appear to be displaced far, far away.