It's generally not a good sign when your best chase day is one of the very first of the year. Alas, 2016 was that kind of year for me. While there were many significant events, I managed to miss out on pretty much all of them, including May 9th in southern Oklahoma and May 24th near Dodge City. However, April 15th was a very good chase day for me, and I had an adventure on May 22nd as well. Pretty much anything beats 2013 and 2014 anyway.
Oh, and it appears I reached the 50,000-mile threshold of chasing this year, probably during the 26 May chase. Here's to another 50,000 more (and then some, hopefully)!
This was my first chase of 2016. Rather late considering the region. Anyway, nothing worth writing about. Some non-supercell storms across southern Oklahoma.
My first non-storm cap bust since April 2014. (I know, right? Who cap busts anymore?)
Convection-allowing models seemed to indicate a high likelihood storms would develop as far south as northern Oklahoma. One model (might have been a 4-km NAM nest run) suggested a storm with very high updraft helicity would track ESE and almost skirt the northern edge of the OKC metro. The key to this forecast seemed to be whether the surface moisture forecasts would verify. Forecasts suggested lower-60s to maybe as high as 64 °F dewpoints would appear in a narrow tongue across western Oklahoma sneaking into south-central Kansas. Oklahoma Mesonet obs confirm that 60 or 61 °F were the highest dewpoints reached in northwest Oklahoma, and such obs were not widespread. Most areas were at 58 or above, though. I didn't check lapse rates, so it's possible that there was too much capping, too, but I blame the lack of moisture.
I didn't think I was going to cap bust. By 3 or 4 PM I was getting to Cherokee and I could see at least 3 or 4 towers going up from west through northwest, with the northernmost one looking the most meaty. I figured that given more heating would still occur, I was sure to get storms. As I worked my way north into Kansas, those towers simply gave up, with the entire CU field around it gradually thinning out and dissipating. By 5:00 or 5:30 I was already sure I had cap busted. I hung out in Harper for awhile, then grabbed some Subway and made my way home, getting back by 9 PM.
The biggest note to me was how wonderfully green the vegetation was across the region. It was very pretty. I love the terrain and road network across north-central Oklahoma and south central Kansas, but I never seem to get to chase a storm there, at least during the daylight. I chased in that area late in the evening of 14 April 2012, after darkness had set in. I did get to chase a tornado on 19 May 2013, although the disappointment from missing storms near home undermined the joy of chasing in that area that day. I field goal busted in that area on 24 May 2011, so that doesn't bring back great memories either. I always look forward to getting to chase a supercell in Garfield, Grant, Alfalfa, Major, Kay, and Noble Counties, Oklahoma and into Harper and Sumner Counties, Kansas (as well as neighboring counties).
Prologue: 26 April 2016 was a Tuesday. The event started one week earlier, when the 12Z GFS run from Tuesday the 19th showed a vigorous negatively tilted trough ejecting over the Plains atop steep lapse rates and very high moisture content for April (surface dewpoints at or above 70 °F 168 hours later. Accompanied by an analog (based on the 500-mb height pattern) to the same day 25 years earlier and an analogous sounding from 3 May 1999, some in the meteorology community began to hype this event as a major severe weather/tornado outbreak. I personally thought it was a little premature to be getting so excited over just one run of the GFS, but other medium range models were in broad agreement with the emergence of a trough of some sort (also neutrally to negatively tilted) over the Plains with some degree of moisture and instability, and the next several runs of the GFS maintained this overall forecast. I remained cautious to promote an outbreak while the hype train had already left the station. I'll admit I was somewhat biased - I wanted the people hyping the event to shut up, so I started looking for chinks in the figurative armor of this setup. Slowly but surely, I found them, but it wasn't until the event came into the range of the NAM before I became more confident. While run-to-run consistency was maintained throughout the lead-up to the event, the different model cores had substantial differences that also persisted. I also did not agree with the GFS' boundary layer moisture forecast suggesting the near-70 degree dewpoints at the surface represented essentially skin-deep moisture, which led to poor instability ahead of what appeared to be the dryline. Forecast hodographs looked outstanding, but the deeper moisture was forecast to be well east of the good shear, essentially east of I-35, which I did not believe. The NAM came in with a much different location of the trough (later ejection), alternative moisture concerns (shallow moisture), and a veer-back tendency in forecast hodographs. It also was reluctant to develop precipitation. I made my skepticism of the event known on Saturday. Gradually, a number of other meteorologists and chasers started to jump on the skepticism bandwagon, so I take some pride in being the first in my known universe to doubt that this setup would result in a tornado outbreak. I was right to be skeptical.
The event proved to be as disappointing as it looked in the days leading up to the event. I chased with three other people, targeting southwest Oklahoma. We got on the northernmost cell of a short line segment of embedded marginal supercells that actually provided some short-lived entertainment. However, little in the way of tornadic activity occurred. Even the giant hail predictions turned out to be too optimistic.
Logan drove in from Denver the day before. A friend of his, Kent, whom he'd known from his days in Minnesota, also drove down to chase with us. Mason drove in from Tulsa the morning of. Together we left Moore at about 11:30 AM, stopping to eat lunch at Fuzzy's in Norman before heading towards Altus on I-44/U.S. 62. As this was Kent's first time in Oklahoma, we took the scenic route through Commanche County, cutting through the Wichita Mountains Wildlife Refuge on the way west. We also encountered two travel delays due to construction and a closed road. That information proved helpful later on.
Anyway, we ended up initially staging at the OK-19/OK-54 intersection near Cooperton while we awaited initiation. We watched numerous towering cumulus attempt to develop into full blown thunderstorms, but eventually a storm developed well to our southwest, near Crowell, TX. After determining that none of the TCu near us were going to mature into storms, we headed towards this established storm, eventually stopping just east of U.S. 183 a few miles south of the U.S. 62 intersection to watch the storm approach. It did not look terribly impressive visually, and its radar representation vacillated quite a bit as well. It wasn't consistently supercellular shaped, and as time went on it became surrounded by new convection upstream. We drifted south, then turned around back north around Manitou as we noticed a lowering form. It was in approximately the correct place relative to the storm to be a wall cloud, but it never gave any obvious indication that it rotated. Radar velocity also never suggested much in the way of rotation. We followed it back up towards U.S. 62 when a hint of rotation finally developed in the vicinity of the lowering. We diverted west from 183 a few miles in steadily increasing precipitation to see if there was anything in there. There wasn't, but we finally saw some aggressive vertical motion with occasional turbulent motion suggestive of very small scale rotation. Upon returning to 183 and turning north, we quickly found ourselves in heavy rain with moderate southwesterly winds, which seemed indicative of our placement in a rear-flank downdraft, consistent with the lowering being due north of us, and also disappearing in the rain. We punched northward as the lowering moved off into the field just southeast of the 183/62 intersection as we approached. This was probably the most exciting span of the chase, as the lowering appeared to begin to rotate noticeably, although not particularly rapidly. We also got smacked by a few hail stones (~1" in size based on the sound it made hitting the car) and witnessed a handful of very close CGs. If this was a supercell, then as we turned east on U.S. 62 we found ourselves in a hook-slicing position northwest of the wall cloud, looking to cut across its north side to get ahead of it. It did not appear terribly threatening, so our "hook slice" was more or less uneventful. We went a few miles north on OK-54 to try to stay with it, and we again entered a rain-filled RFD with moderate southwesterly-to-northwesterly winds. We may have seen some rotation, but nothing imminent. We fell behind it, and knowing that OK-49 was closed near the west end of the refuge, turned back onto 62, cutting through the Cache-Meers highway through the refuge to get north. We wound up back on 62 at Richard's Spur, then made our way through Apache and eventually towards Anadarko before calling off the chase at the intersection of 62 and OK-9 west of Anadarko, where we witnessed yet another brief rotating wall cloud almost overtake us. Obviously it did not produce anything.
We were back in Moore by 7:30 and ate at a Genghis Grill as the now squall line moved through, producing a few brief weak tornadoes across the OKC area.
Frustrating chase due to slow traffic in south-central Oklahoma and stuck just ahead of or in the precip core of what was basically a squall line on what could have been a bigger day.
The approach of another powerful shortwave trough resulted in a quick reload of moisture after the failures from earlier in the week. Moisture looked to be quite good with this system, and indeed low-mid 70s dewpoints made it as far north as the DFW metroplex. Even some low 70s dewpoints made it north of the Red River. However, moisture wasn't so much the problem as was the wind profile. The ugly veer-back pattern was present again, and likely strongly contributed to a messy storm mode. The other odd thing that happened was that the storms that formed in Oklahoma did so behind a boundary that essentially became the cold front as the day went on. And it pushed eastward quickly.
I met up with Jeff Snyder at the National Weather Center. We left Norman around 10:30 AM with an initial target of Wichita Falls. The warm front lifted alternatingly continuously and discretely as we made our way southwest on I-44. It wasn't until we were within a few miles of the river that the sky really opened up, indicating we had transected the front. It was pretty damn soupy on the south side of the front. Obs were in the neighborhood of 81/70.
We lunched near I-44/U.S. 287, then headed up 287 as convection slowly initiated in far southwest Oklahoma. One storm became somewhat dominant as it passed through Altus, and we turned up U.S. 183 towards Frederick/Snyder to get in front of it. We never made it all the way to that storm, as new development occurred to its south as we were approaching Manitou.
The scenario was a little puzzling as we moved north from Frederick. As we approached the storm, it became apparent that it was having trouble getting ahead of a boundary. We didn't think it was the cold front, but the storm never made any progress getting ahead of it and was restricted behind it the whole time. This behavior manifest as a shelfy whale's mouth appearance to the front of the storm. There were numerous dusty spin-ups along the gust front as we moved north on 183; all gustnadoes, and none were particularly photogenic.
It became apparent how outflow-dominant the storm had become as we went east on Baseline Rd. east of Manitou. We had to get at least 10 miles ahead of the core to stay in the juicy air east of the outflow. Not only that, but cloud bases were rather high for 10 °F dewpoint depressions. As Jeff later commented, it seems likely that this storm was not truly surface-based. There must've been a parcel source level above the surface that had less CIN than the surface parcel. The observation was consistent with there being no warm sector convection in Oklahoma west of I-35.
As we approached Lawton the original storm, still well north of us, started to attain a more traditional supercell shape, and rotation developed and intensified. We decided we would ditch our current crapvection and try to get ahead of that storm, but it was approaching I-44 quickly and we were going to have to decide on a route to get to it aggressively, but safely. I-44 provided an aggressive approach, but chasing on any interstate, especially a turnpike, can be quite dangerous because of the lack of exits/escape routes. We decided to jump off I-44 at a side road that went east from Lawton, not expecting traffic to be an issue. First problem: we couldn't find the exit. A few of the exits on the north side of Lawton are for Fort Sill only, and we missed the one we wanted the first time around. So we lost time there. Second problem: when we finally got off where we wanted to, it was 3:30 on a Friday, and it seemed like every single Lawton resident/employee was out and about, even as far east in town as we were. Perhaps they were freaking out about the looming storm which did end up dropping giant hail on parts of town. Third problem: my map deceived me. I thought we would have a clean east road for miles all the way to OK-65. Wrong. Our road turned south without giving us a choice to stay east. Apparently the road I thought we wanted was just inside the boundary of Fort Sill. So that mistake slowed us even more.
Finally we reached OK-65 as reports of tornadoes near Elgin and Fletcher began rolling in. We needed to get north in a hurry. Unfortunately, as we approached Sterling we got stuck behind traffic driving slower than the speed limit. The core of the messy complex (with a tornadic supercell at the north end) caught us as we arrived in Sterling. We had no choice at that point but to turn east on OK-17 and hope we could get to U.S. 81 and north in time to get back ahead of the supercell. Doppler velocities on that storm looked nasty at that time, and it was obvious we were dealing with an HP storm (it probably only produced because it finally latched onto the lifting warm front). Even so, we still had only a narrow berth to get ahead of it...
...Not if Oklahoma traffic had anything to say about it. We couldn't manage more than 45-55 mph eastward and essentially made no progress on the leading edge of the heavy precip. We just barely started to poke out ahead of it as we approached the U.S. 81 intersection. By that time, we had just a few minutes to get north at least 8-10 miles, and the cars that were slowing us down were also turning left. I convinced Jeff to abandon hope on that storm and turn back south, towards the yet undisturbed air ahead of the squall line.
We tried blasting south on 81. For segments where it was four lanes we were able to make good time. But we had to go through Marlow, which was bigger than I remember. Also, south of Marlow and on the Duncan bypass 81 was two lanes, and we almost always had a slow driver in front of us. In fact, south of Duncan we had to follow some idiot with a Texas license plate driving no more than 45 mph, albeit in heavy rain. He seemed to have no interest in making quick passage southward. When we finally got by him near Commanche, we saw he was holding his phone camera in front of him, apparently recording his drive through heavy rain.
We had basically fallen behind the core by the time we reached Commanche. The line was pretty thin at that point, and there was little remaining hope of anything organizing on the south end of the line even though it remained open to undisturbed ambient warm/unstable air. We finally got back ahead of the rain going east on OK-53. Around Loco, we pulled off to watch the shelf cloud catch us once again. It revealed a rather pretty looking cloud texture within the whale's mouth, but we were both frustrated, and didn't care much to photograph it (Jeff snapped a few photos, but I didn't). We "officially" called the chase there and made our way back to I-35, happening to clip an embedded core with torrential rain and some small hail as we turned north on I-35 at the Davis interchange.
Quite a slap in the face from Mother Nature this day. After the marginal success from the day before, I had looked into the potential for the trough to not have yet fully cleared Oklahoma this day and seen the 4 km NAM suggest the dryline would still be west of I-35 in the afternoon with some decent shear remaining. I wasn't in the greatest of moods, however, and that may have been the reason I decided to not chase at all. After a roughly half-day at work, while running errands on the way home I noticed a big honkin' tower not far south of town. I checked radar and saw only a few blips on radar, and so didn't think much of it. I either didn't care or I figured the storms weren't going to be very good on account of the marginal deep shear (which had been increasing in SC OK throughout the day). By the time I got home and turned on the TV just after 4, I got the slap - a photogenic, and not weak, tornado had just touched down in Murray County, just north of the Arbuckle Mountains, and not even a one-hour-drive south of me. It was being live streamed on KOCO, and it quickly strengthened.
I watched the event unfold on TV for several minutes cursing myself before I remembered numerous other storms were developing along the dryline, including a few immediately west of Norman and Moore. One of them passed over my apartment as it was developing a cold pool, dropping small hail without cooling the air. I even saw hints of cloud base rotation even though the storm was not really a supercell. While that storm struggled to get organized and eventually died off, its bigger brother to the south (just passing over Norman) looked more impressive, and after some internal debate, I hopped in my car and headed east through the jungles of Cleveland County.
I was able to maintain a decent view of the entire storm to my south and southeast for pretty much the entire approach. As I got closer, the storm started to exhibit organization and rotation, and became tornado warned as I got north of the core. The storm was very strung out and LP, with the intense core well northeast of the impressive looking and exposed updraft. Lake Thunderbird provided a slight obstruction to an optimal approach from the north side, so I found myself punching through the few-mile-wide core along the east side of the lake, taking hail up to about quarter size as I did so. I finally got between the updraft and the core as I approached OK-9 near the Little Axe school. I enjoyed a fantastic and up-close view of a very mushroom-shaped meso, well clear of precip. While there was obvious mid-level rotation, little rotation was evident at cloud base, but the cloud base was wide and crisp with obvious strands up upward streaming air condensing at cloud base.
I slid to the southeast side of the updraft and followed it ENE for several miles. It attempted tornadogenesis multiple times, with one of those attempts being successful, although extremely briefly (and it barely condensed. In fact, I think only a single picture from a news helicopter showing a very faint condensation ribbon above the ground is all the proof of this tornado that exists). I did not see that tornado, mostly due to the heavy tree coverage in Cleveland County. I followed the storm north of OK-9 towards Bethel Acres where it made one last attempt at tornadoing before beginning a fairly rapid death. However, due to the trees and spotty internet coverage, it wasn't until I popped out in Shawnee that I became cognizant that my chase had ended. Strangely, though, storms immediately to the north - near Stillwater - and back to the south - near Sulphur - continued to rage on for awhile longer. Apparently I picked the wrong area to chase. Not that I had a choice.
So in summary, I missed the biggest tornado event of the year in Oklahoma on a bit of a sleeper day.
This was my OMG-is-the-season-over??? chase where I started to wonder if I was going to see anything more this year. There were no obvious or even subtle chase setups remaining in the week. MPAS had consistently predicted what looked to be an HP supercell developing in the Oklahoma panhandle and moving east through the late afternoon and early evening, but a dryline was also present across western TX with sufficient shear and instability for supercells and tornadoes, assuming storms could actually form. Well, they didn't. Jeff Snyder and I moved along I-40 in the panhandle, sitting in Alanreed and Conway most of the afternoon, before finally giving up and enjoying a trip through Palo Duro Canyon as pitiful CU attempted to develop along the dryline nearby. Another cap bust!
The model forecasts for the northern area verified. A photogenic and marginally tornadic HP supercell materialized and gave chasers in the OK panhandle and the far northern TX panhandle quite a show.
Likely the low point of my 2016 season - I feared a cap bust, but got storms. However, they struggled with the cap. At the same time I was messing around with LP storms struggling against a cap in southern KS, a very long tracked and violent tornado raged 120 miles to my north. Then, after calling off the chase around sunset, a lump of crapvection became organized into a tornadic supercell just northwest of Enid, producing numerous tornadoes between 9:00 and 10:30 PM as I was driving south on I-35. I got there just after the final tornado had dissipated.
I worked a nearly full day at the NWC, not expecting to get a chance to chase. Of the entire week-long span of setups, most declared this day to be the one with the least overall potential. Perhaps they were right, but this was the day with the most moisture and instability. 5000-6000+ MLCAPE was present ahead of the dryline across OK and well into KS with surface dewpoints in the low 70s surviving deep mixing in the PBL. I noted a cloud swirl on visible satellite across central KS and remarked that my target area (assuming I could be anywhere) was Great Bend-Lyons-McPherson, which appeared to be where the center of a surface low was tracking. The storm of the day developed about two counties north of there. Anyway, I was more interested in getting a storm off the dryline somewhere in NC OK or SC KS, so I left at around 3:30 and blasted north.
I was optimistic about getting a good storm once I saw SPC issue an MD and later a tornado watch for the area I had been looking into, although slightly to the north of where I thought I could get. They seemed to focus more on C/SC KS and less on NC OK. I became a little discouraged as I made it into NC OK since I wasn't seeing much in the way of CU developing along the dryline. From my experience chasing in the Midwst, I'm used to cap busts being evident by about 5 PM. However, as I continued to push north, I finally started to notice some harder CU texture through the impressive haze to my west/northwest. But I also noticed an obvious CI occurrence well to my NNE, nearly 100 miles away near Wichita. Already I began to feel the shame of an anticipated bust due to being too late to the storm of the day, as I figured that storm would be the one I would go on to wish I had been on. Around that time, and purely out of curiosity, I checked to see if my ideal target area was verifying. I noted CI attempts in the area, but at that moment, nothing appeared to be hanging on.
I crossed the KS-OK border around 5:20 PM. At that time, a string of turkey towers was becoming evident to my west, along the dryline. Also, the storm well to my NE appeared to be struggling visually, but was maintaining itself. It did not seem to have a very impressive radar signature. The storm in my ideal target area became severe warned, and for a brief moment I contemplated zooming north through Wichita and up I-135 in a vain attempt to target that storm, still fearing an imminent cap bust in my area. I later calculated that I would've made it just in time to that storm had I kept going...I wasn't "playing maths" correctly on that one. That's just a flat out mistake. Then again, it's hard to do all that while driving, as I was solo.
As it went, I got off I-35 at U.S. 177 just south of the KS-OK border to continue into KS to avoid paying the toll for the brief time I would be on the Kansas Turnpike. I was planning on heading north towards Wichita, but ended up stopping in Wellington. There was a nice, empty city park along U.S. 81 in town, so I pulled off and watched as turkey towers continued their life cycles immediately to my west. While they did appear to be growing gradually meatier, it was approaching 6 PM and no obvious CB had materialzed yet. I feared it was going to be too little too late. I was fairly confident I was going to cap bust. I took some unimpressive time lapse video of the towers (unimpressive because I was too close and there were too many trees and buildings in the way...I should've gotten away from town to do this). As 6 PM passed, the towers continued to grow. One particular cluster of towers started looking large and dark, and I became somewhat hopeful that I might actually get a storm. I decided it was time to leave Wellington and headed east on U.S. 160.
As I was moving east on 160, I got spat on - I had precip! It looked like I wasn't going to cap bust after all, although the storm was hardly impressive. It looked shrimpy - obviously struggling with the cap. However, as I continued east towards Winfield, multiple storms began firing to my west and southwest along the dryline, including a more impressive storm back across the border in OK. I wandered around Cowley County for the next hour, eventually settling along 160 just east of Oxford as about the third or fourth storm finally became more impressive looking. It was also during this stretch that I noted the storm I had been watching well to the northeast had dissipated. It looked like it got too far east of the dryline. The new storm to my west/northwest was the first storm that actually appeared to be accessing that 5000+ MLCAPE. After a few minutes, a shallow lowering appeared. I sped west to get closer. I eventually wound up on Oliver Rd. near Belle Plaine, driving into the core of a marginal supercell. Decent structure emerged at the cloud base eventually. Clear rotation was evident in the laminar pattern in the cloud material. However, the base was very narrow, and I saw only weak upward motion into the base. I got intermittent hail of penny size and smaller, and eventually it became obvious that this storm was not going to survive in the fading daylight. The cap was winning again, and this storm was a long way from becoming tornadic.
I retreated back towards I-35, capturing a few photos of the LP storm dissipate in a rather colorful fashion. I had to admit, despite the disappointment in the storm's longevity, intensity, and organization, it died a rather beautiful death. The photos I got at this point were the highlight of the chase.
Ready to call it quits, I moved back to U.S. 81 in Wellington, again to skip the tolls on I-35 and to intercept yet another new storm SW of town that rapidly strengthened. It met a similar fate as every other storm in the area, though, never getting very large and disippating quickly. The cap was definitely winning in SC KS. A fairly impressive updraft remained well to my SW, however. It looked crisp and intense, but radar suggested it was a cluster of crapvection near KVNX. I had no reason to suspect this cluster would do anything different from what its brothers on my side of the state line had done.
I looked for dinner options in Blackwell. Not finding an acceptable option, I ended up going back to the Loves near the Tonkawa exit, where I had fueled up a few hours prior. On the way, I noted the cluster of storms, now to my WSW, was hanging on, but was almost completely void of lightning. The lack of ligtning was sickening, especially given how large and persistent it appeared. It was like a 100 W light bulb that refused to light up despite being connected to a power source.
As I pulled into the truck stop and checked radar, I noticed something that bothered me - that cluster had attained an ominous shape on radar - that of a supercell with a hook echo. Doppler velocity suggested there was rotation in the right spot...wtf...As I grabbed my Subway sandwich, the storm became tornado warned. %&@$! I wolfed down the sandwich quickly, then jumped back in my car and flew south on I-35. I was basically going to have to get down to U.S. 412 and west towards Enid to have a safe play on it. On the way, the storm showed it had become much more energetic, spitting out lightning left and right. I turned on the radio to find a station going wall-to-wall from OKC. Sure enough, people were on it, and it was producing tornadoes...and I was 50 miles away from Enid (which was still 15 miles southeast of the hook). Needless to say, I flew south and west. At some point I had to make a decision. I wasn't confident I would get there in time to see any tornadoes, and the structure from my point of view approaching the storm at a distance was rather impressive. Lightning was coming out of all parts of the storm including the base, anvil, and even the side of the updraft. I considered stopping to shoot structure shots, but my desire to make up for my failure from yesterday (and as I had only learned an hour or two ago, from not continuing north towards I-70) compelled me - I needed to see a tornado, and I didn't care if it was going to be at night.
Predictably, I was too late...by no more than 10-15 minutes. I poked around on rural roads west of town as a second storm right on the tail of the first storm also exhibited signs of organization, but it never reached the levels obtained by the lead storm. There was again disturbingly little lightning in the second storm, and it was very difficult to determine what the little cloud tags I was watching immediately to my north were. Some looked ominous, but then again, everything hanging below cloud base looks ominous at night. I don't think anything was rotating, nor did any funnels poke down. Disgusted, I fully called off the chase at the intersection of 412 and OK-132 several miles west of Enid around 11 PM. Not only did I miss everything in every area this day, but rather than a return time of 11 PM or so (had I never even bothered with this storm), I was now looking at a return of nearly 1 AM. UGH!
What a troll job by Mother Nature. And what happened to that capping inversion on the 17Z LNX sounding? It was completely gone in the 00Z sounding. Crazy to think PBL heating and mixing was enough to mix it out, but it appeared that was exactly what happened. Guess I underestimated the power of PBL mixing at this latitude.
This was supposed to be "the day" for this week of chasing. It was the most synoptically evident setup, and the forecasts leading up to the day suggested a solid signal for an outbreak of supercells with tornadoes.
What really screwed this day over was the fact that the atmosphere over almost the entirety of the state of Kansas convected at almost the same time, right around 18Z, much earlier than the models were suggesting, and well before the peak of instability. As a result, the atmosphere was overturned and stabilized rather early in the day. Jeff Snyder and I had barely crossed the KS-OK border when this happened. The car thermometer dropped into the low 20s °C and stayed there for hours as we zig-zagged westward between Wichita and Pratt. I was pretty sure we were done for the day by 3ish by the time we were in Pratt. Jeff was not as willing to give up.
Amazingly, despite the seeming willingness of the atmosphere to blow so early, after that initial explosion, the rate of new initiation and growth slowed dramatically. All that remained in the warm sector by mid-afternoon were some straggling cells going up off the dryline in NW OK. Those storms were not particularly menacing nor did they intensify or expand as they moved northeast into KS. As they moved northeast, they left the dryline intact and relatively undisturbed. As a result, the atmosphere across W OK and W KS began to recover, just in time for the better shear to arrive. Would the mid-afternoon onset of heating in late May be enough to save the day...?
In some ways, yes. But really, no.
Jeff and I had ventured south from Pratt with an eventual eye set on working our way back home. We stopped for awhile along U.S. 281 south of Medicine Lodge watching the final storms lumber off to the northeast while watching new agitated CU bubble up back to our west. I'm not sure why we did the following, but we started moving west on U.S. 160 towards Coldwater, getting sidetracked by the burn scar from a large wildfire that burned up the entire area earlier in the year. We drove up the dirt road heading towards Lake City, perched on a hilltop for a few minutes, then came back down and back to 160. Not long after we returned, we spotted a large anvil in the distance. This area is notorious for having poor internet coverage, so we had not been getting radar updates. As soon as we got one, we saw a robust storm developing to our WSW, and it quickly became severe warned. As we increased our forward speed to close in on it, it became tornado warned!
We had time to get through Coldwater and eventually stopped a few miles east of Protection on U.S. 183 as the supercell was crossing the road, still a good 10-20 miles to our west. It had an encouraging visual appearance, but the base was a little high and featureless. There was no real indication of cloud base rotation or a wall cloud forming. Eventually we tracked back up north of Coldwater to stay in its inflow. The mid-level structure was pretty, but it remained lackluster in the low levels. When cold, surging outflow overtook us while the base of the storm was still miles away, we knew the chances of seeing a tornado from this storm had dropped to zero. The storm was struggling to maintain its identity and was merging with storms to the north into a line segment and losing its supercell characteristics. This helped our decision to give up, so we headed south back into Oklahoma.
While we were done chasing, several additional storms had formed along the dryline across OK and provided a spectacular early-evening show of shelf clouds and colors. We had to punch through one storm while along the short westerly stretch of U.S. 64. This storm had an intense outflow signature as well as an impressive, bulky shelf cloud. Surface winds, however, failed to match the values seen aloft. Before we got to Woodward, another two storms exhibited a remarkable contrast between a very deep blue and orange hue from the setting sun. It was very pretty...probably the highlight of the chase for me.
My final chase of the traditional 2016 season was a day-after-the-day chase across central and south central OK. Not planning on chasing (interesting theme this month), I worked a full day, leaving the NWC around 5 PM after storms developed to the southwest of Norman. While the atmosphere was not particularly loaded like it had been earlier in the week, there was still sufficient instability and shear for supercells and tornadoes, and a few cellular storms had interesting appearances on radar.
I shot southwestward through Blanchard and south from there towards tail-end Charlie pushing through Stephens County. I managed to find a decent side road that put me in a clear spot on top of a hill northwest of Ratliff City just in time to watch a rather benign looking supercell lumber towards me. In spite of how the year had gone and the lower-end parameters of the day, the storm was quite a sight to behold. I was very impressed with the structure, which wasn't blocked by heavy precip, nearby storms, or hordes of chasers (although they were certainly out there). I could clearly discern strands of horizontal vorticity wrapping around the southeast side of the updraft, almost directly overhead. The storm also displayed a wall cloud, albeit with only weak rotation at cloud base. It was fairly clear there was an ingredient missing on this day for tornadoes, likely low-level shear. A fairly strong, but mild and dry, RFD pulse came in and obliterated the wall cloud and closed out this first attempt at tornadogenesis. Not seeing an immediate attempt by the storm to reorganize, I stayed put on the hill and let the RFD overtake me. I watched in awe as the downward cascading motion from the RFD shunted the updraft overhead and eroded the clouds, opening a very large clear slot with no deep convection (but with fair weather Cu) behind it. The sun then emerged from behind some distant high clouds, resulting in a very pretty springtime storm display. I finally moved south and eastward to stay with it.
Just a few miles northeast of Ratliff City, while along OK-7, the storm reorganized and exhibited some cloud base rotation, and even possibly a very weak funnel cloud that extended over halfway to the ground. It never touched the ground, and the rotation was pitifully weak, but I began to wonder if I might get lucky. I continued eastward, pulling off at Poolville Rd., to get right under where some new rotation was developing. It got fairly windy at this point and I wondered if a weak and broad ground circulation my have crossed the road nearby, as the clouds above were really moving, but no obvious funnel ever emerged.
At this point it appeared there were several separate areas where the cloud base would lower and look slightly ominous for a few minutes, perhaps weakly rotating, before dissipating. I made one final stop a few miles northeast, again along OK-7, to watch many of these areas. Several times I was hit by a warm RFD surge only to have the winds turn back to inflow and then back again. After a long time, a sustained and large lowering developed and maintained itself, now well off to my southeast, so I rejoined the pursuit. I punched through the core to get back to I-35 (there were no other routes as I was passing the Arbuckle Mountains), then drove through Davis as the lowering loomed just off to the west. The lightning was impressive, but the storm never organized enough to excite me, so I eventually decided to end the chase there. I caught a rainbow from the backside of that and neighboring storms as I headed home. I also recall seeing the anvil extend quite a ways off to the north, not northeast or east, of the storm. Upper level storm-relative winds were very strong and backed, resulting in notably aberrant behavior of storm anvils. Anyway, not a bad way to end the season.
This day had been forecast to be a potentially big event for October. As it happened, it appeared the 850-700 mb layer was a bit warmer than predicted, and so much of the southern portion of the risk area remained capped. What really got everyone around OKC excited was about eight consecutive HRRR runs in the morning and afternoon that forecast a nasty looking rotating storm impacting the OKC metro or just south of OKC in the late afternoon. That storm eventually materialized, but about an hour or two late, and it struggled to organize, probably against the cap in increasing darkness. The 00Z Norman sounding ended up being rather impressive shearwise, but the storm itself could not attain any remarkable low level rotation.
I left Moore at around 3:45 and made it as far as the Chickasha oasis on I-44 before stopping and watching the CU field southwest of me dissipate as the cap won. I turned back at about 4:45. I think the storm developed after that due to increasingly backed surface flow, which was stronger than forecast, and thus was the result of stronger than forecast surface convergence. The moisture forecasts of upper 60s dewpoints actually verified. If only mid-level lapse rates had been steeper.
I wasn't done making bad decisions this week. Following Tuesday's (the 4th) bust, I for some reason decided to drive north on I-35 towards northern OK where CAPE and shear were sufficient for supercells and tornadoes. The main problem seemed to be the cap - pretty much all storms that went up in northern OK ahead of the cold front struggled with it and eventually died. Tornadoes occurred in northeast KS and supercells produced giant hail in western OK and northwestern TX, but the 100 miles around me were essentially void of interesting weather.
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