2012 Season-Opening Success in Southwest Oklahoma
SW OK
18 Mar 12
SHORT: Intercepted merging storms then resulting single supercell over SW OK, with spectacular structure and three short-lived tornadoes.
LONG: A little advanced planning made possible a splendid start to the 2012 storm-intercept season, on the 87th anniversary of the Tri-State Tornado.
Before Tornadoes
My daughter Donna and I headed out from Battlestar Norman at 19 Z, thanks to 1) her outstanding academic performance and judicious spring-break homework planning that freed her this time to chase, 2) her ability to drive to meet me at work, and 3) Greg Dial’s swapping shift hours with me from the previous day. It was a good day for some dad-and-daughter time on the highways and byways of southwest Oklahoma. We targeted the LTS/CDS area, well-advertised for a few days as part of a corridor of dryline supercell potential.
Forecast thinking was that early cloud bases would be somewhat high, but storms likely being discrete given the presence of modest capping and decent component of mean-wind orthogonality relative to the dryline. Low-level and deep-layer shear would be more than sufficient. Boundary-layer moisture would increase as storms moved off the deeper mixed layer air of the dryline environment, deeper into a moist sector.
As we cruised W across the N side of Lawton (S edge of FSI), we started to experience promising breaks in the low clouds, while the first robust reflectivity echoes sprang up SW of CDS and E of Crosbyton. I immediately targeted the northern echo because it would be moving into: 1) the forecast target area, with a somewhat more favorable environment slightly sooner, and 2) a better road network over SW OK than for the storm headed to the Crowell area. Both of these would evolve into supercells eventually, along with a third echo farther S.
As we approached Hollis, the small, young storm came into view, still well to our SW near CDS. Being a softie for abandoned structures of the Great Plains, I couldn’t resist parking at a wondrously decrepit old house, located 3 E of Hollis.
The westward-listing relic of the homesteading era creaked in the wind, as if mournfully moaning some of the last words in its long and mysterious life story. A loose strip of sheet metal on its roof flapped hither and yon in the prairie wind, its clanking noise advertising the structure’s vulnerability for all to hear, but with only us listening. Yes, the old house was well worth shooting, both in its own right and as a foreground for the approaching storm.
Moving generally toward us, the storm became better organized, until distinctively supercellular bands and striations materialized. We repositioned a couple miles east to distance ourselves from the vault’s lightning production, while its base expanded. Another rotating storm formed just SW of the Hollis storm’s flank and moved NE, dumping its own front-flank precip into the back edge of the first storm.
Cloud-base spin began anyway, along with intermittent pockets of faster rotation and rising motion with lowerings (looking W). The first serious occlusion wrapped a good deal of precip around the low-level mesocyclone, with a short-lived, conical, rotating lowering that might be termed a ragged funnel cloud.
Meanwhile, as our gradually merging storm(s) got messier, things got very interesting 60-70 miles to our S. The classical, flying-eagle reflectivity appearance of the middle (Crowell) supercell tempted me enticingly, especially when the red polygon showed up. Despite that storm’s digital allure, we stuck with the northern storm based on visual cues, even through its struggles with mergers and resultant HP-like precip cycles.
Here’s why. The storms’ merger cast a lot of messy precip across the scene, but somehow didn’t kill the initial supercellular rotation area. We would stick to our original target. This was purely an “eyeballs” decision. On reflectivity animations it did look like a disorganized mess. Visually, it still was conducting a series of occlusions. Good thing I trusted my eyes more than radar this time!
While I’ve found wireless radar access generally to be a benefit in the years since its availability, this event was a fine example of how onboard radar access sometimes can be a curse instead of a blessing. When visibility sucks, and all you have to work with is radar, you go for the storm with the best organization, if the environments are somewhat similar. In this case, however, the nowcast environment also was a little better for the northern storm in terms of slightly weaker CINH, and similar to slightly stronger SRH in another 2-3 hours. It was a gamble of patience that paid off.
First, however, the messy, temporarily HP storm character brought down contrast (wide angle view looking NW) as the whole process churned northeastward. A new area of rotation developed ahead of the old, rain-wrapped circulation, as the storm(s) gained distance from us. It was time to reposition N and E through Shrewder. This meant going N six miles on a narrow but hard-packed dirt road if we were not to lose visibility. One stop W of Shrewder afforded us a view of a new and old meso with rainy pseudo-nado (looking NW). Meanwhile, that portion of the second (merging) storm that appended itself to the flank of the first began to exhibit some wild striations nearly overhead to the SW.
Upon seeing that, I knew the combined storm was evolving into a wedding-cake special, and we needed to get many miles farther NE to get enough of the storm in view for decent structure shots. We zigzagged through Russell and Mangum toward Brinkman, watching a couple more occlusions and short bursts of moderate cloud-base rotation. One stop near Russell afforded us this splendid view to the NW. We turned W from US-283 onto a paved road running S of Brinkman, looking SW toward the Reed area, and toward a stunning, sculpted supercell.
Tornadic Stages
While admiring the structure, I spotted something tubular emerging leftward (southward) from either within or behind a rain core under the base. Donna shouted over the wind, “Hey dad, is that a tornado?” I shouted back “Yes!” and managed to snap just one photo of the serpentine vortex (alas, with the 24-70 mm glass still attached…here’s a cropped version) before I reached into the car for the zoom lens. Time was 0004 Z. By the time I got the 300-mm lens on, the little tornado was gone, the area where it had been exhibiting only a scuddy lowering and some precip filaments. I don’t know how long the tornado existed before it popped out of the murk, but can’t imagine more than a minute or two. I called it in to the WFO, advising that the tornado had dissipated. [A couple of subsequent attempts to call during later events would be met with busy signals.]
Remarkably, this was Donna’s first tornado on a chase! She soon would add two more. Donna had been on 15-20 tornado-free storm intercepts with me over the years, and had seen three tornadoes while not chasing.
Staying in the same spot, we let the storm approach rather uneventfully, watching one more non-tornadic occlusion occur, then decided to head back east and gain more distance for structure shots. As I drove, Donna and I (she with direct sight, I via rear-view mirror) each noticed a smooth lowering forming in a somewhat rain-wrapped mesocyclone to the distant WNW. We turned around and pulled over at the first safe vantage, 5 E of Willow OK, right alongside Bruce Haynie and his chase partner Matt from LBB. The lowering was a funnel that rapidly became apparent as a tornado. Time was 0029 Z.
The condensation tube fattened into a tilted, tapered cone, while the clear slot eroded more ambient cloud material and a core dump grew to pseudo-tornadic form elsewhere in the mesocyclone area. A real tornado and a lookalike, all in the same view! Here was a 300-mm zoom at 0029 Z, seconds before the tornado appeared to dissipate.
Dense precip filled the entire mesocyclone below cloud base, and we started heading E again. We were just half a mile W of OK-6 and 7 N of Granite when another lowering showed up in the rain–tornado 3. This time, contrast was very poor, as was my attempt to photograph it (see deeply enhanced version). Time was 0039 Z.
Better vantages were had from both closer and farther away, and more to the NE. At this moment, I was located in that netherworld between close enough for a good shot of the tornado, and far enough to pull out structure. Sometimes a storm observer’s timing is off that way, but I’m not complaining…Donna got to see her third tornado of the day. Shortly after the tornado roped out (within a minute), we noticed a suspicious cloud lowering deeper into the precip, probably in an older occlusion. The feature was just too distant and low-contrast, beyond intervening trees, to determine its nature (severely enhanced crop).
Post-tornadic Period
On the way to Retrop, we stopped to view the majestic and now non-tornadic storm, exuding ghostly pastels in early twilight, here at wide angle looking NW with a mobile radar that wasn’t scanning. When we turned back onto OK-6 to head N, we saw that the radar truck was parked smack in the traffic lane–since then I’ve learned that they were broken down in that spot instead of stopped intentionally.
We stopped one last time, a few miles E of Retrop, to watch the storm go elevated and weaken in the deepening twilight. We were satisfied beyond measure with our first chase of the season, and fortunate to have experienced such a phenomenal storm with minimal hassle. We managed to avoid the worst of the chaser hordes, and saw generally safe behavior even in traffic.
Given the late hour by the time we reached the next sizable town (Cordell), celebratory steak dinner would have to wait until the next day. We did, however, enjoy some Sonic food, followed by a little more dad-and-daughter time on the couple hours’ drive back home.
[EDIT] Post-chase, I learned that my camera clock was 6 minutes slow. The clock has been reset, and the times above corrected.