Elaborate Tornado Avoidance Techniques

July 27, 2013 by · 2 Comments
Filed under: Summary 

Southern Kansas to east-central OK
19 May 13

SHORT: Intercepted 4 supercells in 3 tornado warnings and saw no tornadoes: 1. NW of Ark. City KS, 2. near Parkland OK (middle storm of OK triplets), 3. ENE of Prague, 4. Near Okemah and Okmulgee. Somehow managed to miss all the tornadoes two days in a row.

LONG:

Setting up “the day after the day before the day”

Having intercepted clearly the most unfavorable of several Kansas storms the previous day, the “day before the day”, Rich T and I were determined to get on a tornadic supercell on “the day”.

A classical setup set up for the corridor from southern KS to central OK, with rich low-level moisture return, a strong dryline, a lack of antecedent precip to mess up the boundary layer, large low-level hodographs, and strengthening deep-shear vectors with a decent component across the dryline. In short, this was a prime southern-plains tornadic-supercell regime, the only potential hitches being mode certain initiation with storm-mode concerns up north (near a cold front) and initiation questions farther south.

Our strategy, therefore, was to get in between the two ends and be in prime position to strike like a predator at the best developing storms in a corridor from OKC-ICT. We arrived early at a truck stop N of Perry and awaited development. Early storms near ICT looked interesting, even supercellular and potentially tornadic, (one did produce there), but also, potentially tangled up quickly in a messy cluster near the front. Fateful decision #1 had been made: blow off the early, tornadic ICT storm for more discrete and ostensibly longer-lasting activity to form closer, later.

Two areas of convection began to develop almost at once: just W of us, moving NNE toward Wellington, and about 75 miles SSW of us, on the NW fringes of the OKC metro area. Either was easily reachable. We had much better visibility on the closer activity, which seemed likely to remain in a favorable environment well into mature stages. Fateful decision #2 was sealed: check out the closer storms, which would take us away from central OK. We had seen this picture play out several times before–jump on middle or northern convection only to have the southern storm near OKC produce tubes (whether or not we would see one with our convection). Still, we risked missing something closer to home for something closer to us.

(Somewhat) northern play

Fully aware of that dubious history, we headed N to near Blackwell and took a look at the growing Cb, already showing some supercellular characteristics on radar–as did an initially separate, trailing storm behind the cold front and to our storm’s WSW. This is how it looked before the base came into view. We hopped N of the border, zigzagging E and W a little across I-35 N of Wellington to get in viewing position. The storm turned out to be a messy HP with poor contrast. Only a brief, surging attempt to wrap a mesocyclonic occlusion was visible, with a funky, spiked, ground-tickling tail cloud, before it buried itself deeply in rain again.

Optimism wasn’t the word here. The storm had 1) accepted a cascade of percip from the dying remnants of the post-frontal supercell, 2) dealt with big towers and showers forming and merging into its rear flank, and 3) interacted with a new, quasi-linear frontal segment nearby. Meanwhile, radar showed the storms near OKC coalescing with frightening speed into a big, honking supercell near Edmond. This is when we started getting that sinking feeling…here we go again.

Back to central Oklahoma

Fateful decision #3 actually didn’t take long: let’s not linger with this HP rubbish, and try our best to bust SSE ahead of the now violently tornadic convection just NE of Edmond (or anything that might form farther upshear). We didn’t dither on this, which made an intercept from that distance at least marginally feasible. Somehow, the at HP rubbish, and accessory convection building into its flank, produced a small but photogenic tornado near the South Haven exit of the Kansas Turnpike…not long after we left!

Unaware yet of that morale-crushing development, we made decent time southward on US-77/177 through PNC to the Cimarron Turnpike, then SE on the speedy slab. All the while, we could see the booming, huge flanking towers rolling into the back side of the leading storm, now near Stroud, with a known history of atmospheric violence. However, as we closed in for a potential end-around the back side, potentially in the Bristow/Kellyville area, the convection was softening, the mesocyclone weakening, the storm moving into somewhat cooler, lower-theta-e air.

Resigned to missing all that storm had to offer, we saw two newer supercells on radar, and fuzzily from the sunny N side–a small one to our near SSW, near Carney and trailing behind the first. The westernmost storm was organizing fast…over Norman! That was the cell we really wanted to see, with its unimpeded inflow and longer prospective resident time in juicy air…but the middle storm (which was sucking some outflow from the formerly tornadic lead supercell) was smack in the way.

Since the middle storm was considerably smaller than the others, with lower VIL and MESH hail indicators and a thinner forward-flank core, we made fateful decision #4, hedged a bet against the risk that could strengthen its hail production, and headed S through its forward-flank core toward the Agra/Parkland area. True to its algorithmic evolution, that core indeed contained only marginally severe hail and was surprisingly translucent, allowing us to pop out of precip a safe distance of 4-5 miles ENE of the storm’s mesocyclone. We could check this out briefly while plotting a course to get ahead of the Norman storm, by now producing a tornado over Lake Thunderbird–just a few miles from both my house and Rich’s. That sinking feeling came back again.

Yet we weren’t obligated to leave this storm just yet, not with us in an unusually good vantage point for this hilly, forested part of the central Oklahoma crosstimbers, and a tightening mesocyclone approaching rapidly on track toward a spot on the highway immediately to our north. From a distance, the main cloud area was so low that it might have appeared tornadic, but we certainly were close enough to confirm otherwise. As it crossed less than a mile away, the persistent, deep, scuddy lowering was rotating, but not especially fast, and had no debris or dust beneath. Inflow felt rainy and somewhat cool the whole time, which seems to have been more related to the earlier storm than this one. Nonetheless, it tried hard (deeply enhanced crop)…just not hard enough.

Having spent just a few minutes examining that supercell, we made our expected run for the former Norman storm, now approaching Prague, offering a tremendous radar signature, and yielding terrible media-broadcast tales of tornadic destruction from the Dale-Shawnee area. By the time we got to I-44 and US-377, it was obvious we would have to either: 1) make a big zigzag to take a safer approach, or 2) penetrate this storm’s forward-flank core too, but come out perhaps even closer to what was known to be a dangerously tornadic mesocyclone on 377.

No, thanks…fateful decision #5–live to chase another day! I don’t know what would have happened had we turned stupid and tried to core-punch that sucker, but I’m glad not to know. Even though the NWS tornado mapping for the event shows a break at 377, the risk was too great…and of course gorilla hail can take out a windshield and end a storm intercept quickly. Notice also the tornado path NE of Prague, between there and Welty (the W road E0960 off OK-48, halfway from Bristow to I-40).

Zooming safely ENE on I-44 then S on OK-48 toward Welty, we passed instead through far-forward-flank precip that was dense but only rain. We passed through hilly terrain near Welty and hunted for the first relatively open view of the big supercell that wasn’t right in the path of the meso. By the time we saw the storm, looking W on side road E0980 S of Welty, it was a deep, dark, low-contrast, HP drum. The storm definitely was producing a tornado at the time based on official mapping, but one we just couldn’t see with our eyeballs because of extremely dense wrapping precip. At the time of the last shot, the tornado would have been directly down the road, in the distance (deeply enhanced crop).

Shortly after I walked a little way down the road to try a different angle (deeply enhanced crop), a small car pulled up. The unknown chap inside noticed I was shooting the storm, and started an impressive routine of big-timing, offering instruction about the supercell’s structure and what was going on where. His descriptions were fairly accurate in a general sense, but this presumptuous little game was wasting both of our times and just had to stop. I’ve seen and studied a supercell or two myself over 28 years of storm observing and professional meteorology, so it was hard to resist temptation to bust out laughing. Instead I decided to have mercy and let him off the hook relatively painlessly. Once I could get a word in edgewise, I succinctly discussed the likely pattern of vorticity lines around the wrapping, precip-filled occlusion downdraft and its interface with the forward-flank gust front of a supercell of this configuration and morphological stage. [Thank you V.O.R.T.EX.] Quickly my interlocutor quieted down and turned his attention back to the storm. 🙂

Duly amused and a bit grateful at not being recognized, and not wanting his vehicle (or its glare) to take up too much of the shot, I wished the dude good luck, and jogged back up to the vehicle. Rich (who had stayed by the vehicle) and I watched hard for any evidence of the ongoing tornado somewhere in there (deeply enhanced crop). The rotation of the precip cage and surrounding cloud deck was impressive, but we still couldn’t see the tornado by eye. Even the deep enhancement leaves room for doubt.

After that, the visual appearance got even messier, the mesocyclone shifted NW then NNW of us, and RFD precip began to hit. We bailed S, glancing back at the remnant circulation crossing behind us (by then nontornadic, as it turned out) expecting that to be our last view of the storm in the fading daylight. An awful lot of rain was falling well S of the hook of our previous supercell, and once we got out of a cell-phone hole and saw radar again, it was obvious why. Yet another supercell had gone up farther SW, playing a game of mutual hindrance with the former Norman-Shawnee-Prague storm. They were aligned in ideal geometry to dump rain and/or outflow into each other’s inflow regions!

Enough was enough

Despite its ragged and somewhat high-based appearance (looking NNE from near Castle), we followed the last supercell N a few miles out of Okmulgee before twilight and unimpressive structure mercifully ended the intercept. Somehow we had witnessed four supercells and no obvious tornadoes on a big-event day, and aside from that, had seen very little in the way of photogenic structure. On top of our chase failures the previous day, this dealt a most demoralizing blow; and that wasn’t the worst of it.

At some point in there, I learned that the beloved cat Iniki, who suddenly had fallen ill a couple of days before, had to be put to sleep by an emergency veterinarian the same evening, while I was out driving hundreds of miles and failing to see anything of note. I never got to hold her and say goodbye. This day officially sucked. How could doing an activity I loved so much get so stinking miserable?

We ran into Bobby Prentice and Scott Fitzgerald at an Okmulgee gas station, hearing of I-40 being closed on our way home due to tornado damage (indeed, it was). We didn’t need more bad news. Yet, to make matters worse, we then learned that the Shawnee tornado had been a killer, and also, crossed the power-supply lines N of Rich’s house and cut electricity thereto for many hours ongoing. His food was unloaded into my fridge and big freezer, and he stayed at Elke’s and my place that night.

Our wish for the 20th was to turn the heretofore painful storm-intercept fate of the previous two days around on the third and final day of this weather system, despite fighting the urge not to even bother…

2010 Chase Season Dénouement

August 14, 2010 by · 1 Comment
Filed under: Summary 

22 Jun 2010
Southeast WY to North Platte NEb

SHORT: Outflow-dominant supercell observed twice — once in SE WY and another in NEb Panhandle. Gorgeous sunset supercell S of Paxton NEb.

LONG: We were hoping for one final photogenic supercell for our chase vacation, and instead got two.

A piping hot lunch at a local cafe in downtown Sidney NEb, featuring a platter of smashed and fried Rocky Mountain oysters, settled down hunger’s restlessness just long enough for us to watch satellite imagery on the mobile phone, seeking first signs of convective initiation on the Laramie Range to our W. This area would experience favorable upslope flow, decent low-level shear and deep-layer winds, along with sustained surface heating in the absence of any appreciable, antecedent cloud cover, but moisture seemed a tad on the scant side. Once the first towers started to fire NW of CYS, we hopped onto I-80 and roared westward.

By the time we got to Pine Bluffs WY, deep towers were visible with glaciation to our NW. We could see the cloud bases easily, so we fueled at a truck stop there as I chugged down a cold, delicious A&W float. I also reserved a room in LBF for the night using a combination of forecast storm motion and positioning needed to go back home the next day, while watching for a storm to congeal and organize from the agitated area. Soon, it did, and we took off W through Burns and then N, retracing in reverse a segment of our chase path from the tornadic Chugwater event two days prior.

True to the lack of more robust moisture, the bases seemed uncomfortably high, and I was troubled further by how fast the cells started moving E off the mountains as we approached. Was the convection already spewing outflow? Yes! We barely beat the storm to the intersection of WY-213 and WY-216 W of Albin, near which I shot this photo looking W. Yes, there were updraft bases all right, but they were being undercut very quickly by wickedly cold currents hurtling SE from the precip cores. We headed E on 216 to Albin, having to make a decision there either to:

    1. Take unpaved back roads and stay closer to an outflow-surfing wind and ice machine, risking its outrunning us for good somewhere not far E of the WY-NEb border, or

    2. Shoot back down to I-90 and bust eastward at higher legal speeds so we could stay abeam and eventually get back ahead of the storm on a north road.

Although I’ve seldom seen such an outflow-dominant storm recover to produce tornadoes, it has happened on one occasion. Furthermore, such storms can produce interesting and sometimes beautiful cloud formations, especially out on the high plains. The decision was easy.

Meanwhile, before zooming down to the Interstate, we watched the storm cross the road to our N, spying a suspicious-looking but very short-lived formation buried in a mesocyclonic notch region (enhanced crop-n-zoom of previous image). That feature quickly vanished, and the whole messy and wild-looking process roared past.

By the time we got just the few miles S to I-80, the storm already had gotten well off to the NE, brilliantly festooning a deep blue sky (wide-angle view from I-90 near the border), with a high and ragged base visible on the trailing flank. That, along with the main updraft base of the storm to our left, were visible as we cruised E to Sidney, then N toward Gurley — in the process retracing a late-day segment of our trek from the previous season’s intercept of the LaGrange WY supercell. For our nearly continuous view of the updraft while driving, and several chasers who were closer at that time and didn’t see any tornado, I had to question the “sheriffnado” reports just E of the border in NEb.

We got directly ahead of the storm again E of Gurley, watching its somewhat-lower base with a small, shallow wall cloud developing to our WNW (wide-angle view) while a deck of low clouds formed overhead. The storm itself was decelerating markedly, and its own outflow boundary appeared to outrun its main reflectivity area (and mesocyclone aloft). I got a dread that the supercell wouldn’t last much longer; and it certainly did not. A zoom view shows the wall cloud that was surrounded by translucent precip. Within minutes, a fuzzy gray bowl of precip appeared right in and under the wall cloud, descending and expanding and obliterating the wall cloud as it reached the ground, and making a splendid example of a tornado look-alike.

Was this a descending reflectivity core (DRC) that came down in a very deleterious place for any low-level mesocyclone’s development and survival? It sure seemed as such. Here’s the view 3 minutes later, when the precip core further expanded and utterly obliterated the cloud base where the wall cloud previously had dangled. Within 11 minutes more, the outflow had gone past, the low clouds cleared away to reveal an astonishingly rapid storm demise!

Thinking that was it for our chase season, we headed E toward LBF, only to see a stunning and spectacular convective eruption to our SE, S of Paxton, beneath a waxing gibbous moon and shortly before sunset. As this storm evolved into a short-lived supercell, we admired the amazing spectacle from a corn field a couple of miles S of the Interstate, until an inverse relationship between amount of sunlight and mosquitoes hastened our resumption of the trip. What a wonderful way to close out the last chase of Spring 2010!

When we settled into our room in LBF, the clerk remembered my call and said we were smart to do what we did many hours before; all the rooms in LBF were booked up solid! After 11 p.m., we noticed a dramatic increase in lightning to our N-W, as storms erupted along the outflow boundary. While cruising S of town in search of a good vantage in that direction, the storms weakened again, precluding any decent lightning photo opportunities, though we did salvage a nice look at lunar crepusculars around an altocumulus deck.

This was a rewarding day, one that left us in ideal geographic position to do something we had wanted for a long time: pick up a stone fencepost from one of the quarries near RSL. It would be right along the way home the following day. Our adventure in doing so was a marvelous glimpse of Americana, chronicled in more detail in this BLOG entry. The d̩nouement had been written on our chase season Рone that was, at times, agonizingly frustrating, and at others, as fulfilling as can be. What adventures await in 2011?

Clam’s Foot Surfer

July 1, 2010 by · Comments Off on Clam’s Foot Surfer
Filed under: Summary 

Dumas TX and vicinity
12 Jun 10

SHORT: Observed outflow-dominant line E of Dumas, elevated stage of supercell SW of Dumas that hailed over us at dinner.

LONG:
Elke and I began the day with a cold breakfast at our Burlington motel, joined by Chuck and Teresa Robertson, then Matt Crowther and Vince Miller, all of whom also had intercepted the Limon-area supercells the day before. The cold front was surging farther S, faster than forecast the previous day, so we all had to get out of town soon and jaunt down south to the Panhandles. For Chuck and his lovely bride, who live in the northeastern TX Panhandle, it would be a return home, with storms along the way.

After a couple of hours on the road, we stopped to pick up some provisions at the Wal-Mart in Lamar CO. On the way to the rear latrine, I spotted a familiar human form — there was Vince, picking out a shirt in the clothing section! What are the odds? A short chat with him and Matt outside, and we all were back on the road again. We wouldn’t see either of them the remainder of the day. Still, in storm observing, such are the unplanned, chance encounters one can have with familiar old friends and acquaintances.

By the time we got to Boise City OK, storms already were firing along the cold front to our S and SE in the TX Panhandle, with big towers erupting beyond the cool, foggy haze. The most robust of those went through a briefly tornadic supercell phase well before we could get to it, then turned into a large HP mess. We thought about “rounding the corner” on it E of Dumas, but by the time we committed to that plan and got near it, the entire complex had degenerated into this rather amorphous, outflow-spewing mess, all while dumping nearly a foot of rain from train-echoes near Morse.

Another fun serendipity of storm observing is being in the same place twice, hundreds of miles from home, on different days and different storms, in the same season. Such was the case with the last photo, which I took on FM-1060 while less than a hundred yards from where I shot the mesocyclonic merry-go-round E of Dumas the previous month (see You Decide, 18 May 10). We retraced steps from that amazing May day eastward through Stinnett and north a few miles, but without such intense atmospheric results.

While shooting time lapses N of Stinnett, David Hoadley pulled up and chatted with us for awhile in the cool outflow. It’s always a pleasure to see Dave again, as I seem to do about once a season at some random rural pull-off near a storm. Some new cells were trying to fire south of the outflow boundary and W-NW of AMA, so Dave and I agreed that was the only remaining viable target, and parted ways, independently heading the same general direction. Along the way back to Dumas, Elke and I stopped to shoot a couple of peculiar, fascinatingly illuminated and somewhat convective scud formations (first and second).

One longer-lived cell had crossed over the arching outflow boundary SW of Dumas but remained intense on radar, so after grabbing a motel room there, we drove a couple of miles S of town to take an unobstructed look. We still were in cold NE outflow from the massive complex to our NE, and this storm was obviously elevated at the time, exhibiting laminar formations and riding atop an elongated, clam’s-foot cloud formation (wide-angle view looking WSW) as the chill breeze at our backs strengthened further. Ribbed texturing to the main low-cloud band, glowing in twice-reflected, late-afternoon light, formed an uncommon and striking visual backdrop for the wind farm SW of town.

Thinking somewhat erroneously that the storm would remain elevated, we ate dinner in Dumas as it rolled over us, profusely peppering the restaurant windows with a protracted blast of hail near an inch in diameter. I was tempted to run out and grab some hailstones as ice for my drink, though the Moore County Health Department might not have approved of this item on the menu. It turns out that the supercell backbuilt and right-moved, once again getting close to the eastern segment of the curving boundary, and becoming surface-based again to our E, after it left town. We finished supper and headed a few miles SW of Dumas hoping for sunset photography, but with all the various clouds in the way, all we could salvage was some twilight pastels over ripened wheat.

We slept well that night, knowing that the next days’ target would be in the Panhandle also, but not knowing that we would see both a pretty tornado-producing supercell and the largest amount of standing water we’ve ever witnessed on a High Plains storm intercept.