My planned blog post for this week was an anniversary retrospective about the Earth Day tornadoes I witnessed near Alanreed, Texas one year ago today. Those tornadoes were somewhat ambiguous in number (between three and seven, depending on who you asked), slow-moving, and accompanied by turquoise precipitation bombs. Little did I know that the scenario would unfold similarly a year later to the day.

I really wasn’t supposed to be chasing today, but brought the car and camcorder to work “just in case.” And even as the front zippered up all the way from Joplin, Missouri to Oklahoma City in about half an hour, I still waffled until the absolute last minute. The crisp convective towers outside my window tempted me outside to shoot some time lapse footage in the NWC parking lot. From there, of course, it was only a quick hop into my car and a straight shot east once one of the line segments transitioned into a supercell.

Our initial target was a supercell east of Seminole, OK, the site of our bust chase last week. However, as we left Norman around 5 p.m., we got stuck behind a large utility truck that couldn’t do more than 45 mph on gentle slopes, and I didn’t feel safe leapfrogging the 20-car convoy that accumulated behind it. Thankfully, they pulled over at a gas station, and we raced east to Seminole. By then, the supercell had moved off to Okemah, and we had become aware of additional supercells developing (including one over east Norman), so we decided to hold up in Seminole for a few minutes to re-evaluate.

We changed our target storm and intercepted it just east of Shawnee, OK. It produced a brief wall cloud, but its inflow was clearly being contaminated by precipitation from the Norman storm, and we soon lost sight of it in the rain and decided to let it go. We zigzagged back south and west through Shawnee, intercepting the Norman storm near Macomb, OK. It generated a wall cloud, and even a cascading, precipitation-filled clear slot on its back side, but no tornado. We watched it move away alongside a clutch of other chasers.

We had to decide whether to continue pursuing the Norman storm as it moved off to the ENE, or drop south to another cell just east of Pauls Valley, OK. Fortunately, storm motions were reasonable (15-20 mph), giving us time to wait for one more radar update to inform our decision. The Norman storm had begun to congeal with its neighbor storms, so the clear choice was to drop south on U.S. Hwy. 177 toward Asher, which we did, coring the Pauls Valley storm as it moseyed east. We never saw any hail larger than dime size. At one point, we experienced a sudden wind shift from NWly to SEly, as a lowering passed by to our north, in the rain. (Later, we received a text message from a fellow chaser, concerned that he had seen us pass almost directly underneath a mesoanticyclone.)

We passed by RaXPol, on her maiden storm chase, parked near the intersection of U.S. Hwy. 177 and OK-59, just east of the town of Byars. We continued south for two more miles, and observed a dark, dense mesocyclone off to our west close to sunset. We stopped near Peach Crest Farm, and watched scud being rapidly ingested into the accompanying lowered cloud base. I knew our odds of seeing a tornado were increasing by the minute. As I drove another mile south, chasers parked along the highway suddenly started waving and pointing their cameras toward the west. We pulled over, and this is what we saw:

The time stamp on my video says 8:00 p.m. at the time of the first funnel, and I had just synchronized my camcorder to GPS time that afternoon, so I’m certain that it’s correct. The second pair of funnels occurred at 8:02 p.m.

Our target storm began to dive southeast, toward Ada, OK. The mass of precipitation to our south continued to grow greener and more ominous, so we retreated back north. Along the way, my husband managed to pull a RadarScope update on his phone, and we were rather shocked to realize that we were looking down the maw of our storm’s inflow notch. Not a good place to be!

We encountered RaXPol, containing classmate/fellow chaser Jeff S., my former adviser, Howie Bluestein, and their ARRC engineer (John). They had collected data in an earlier wall cloud, but did not collect any data in the tornadoes. They decided to call it a night and headed west along OK-59, and we decided to follow. Along the way, we encountered some debris just east of Byars – some sheet metal peeled off a barn was blown from the north to the south side of the highway, gravel scattered across the road surface, and a power pole blown down nearby. As we gingerly tried to navigate the debris, some intellectual luminary two vehicles ahead of me got out, picked up the wet power line with his bare hands, moved it out of the road, then got back into his vehicle and drove away. All I can say is, thank goodness the line was dead! I could have witnessed a Darwin Award in the making. I’ve asked around, and I am apparently the only one who noticed that this happened, and unfortunately, I had turned off my dash cam just a few seconds before, so for all you know I could be making the whole thing up.

As we drove back toward Norman, we witnessed some spectacular lightning in the backsheared anvil. Many of the CGs we saw today (which were numerous – and close – hence our failure to exit the car in the video clip) had spectacular structure, appearing to loop back on themselves multiple times. There was also a terrific display of mammatus, but the sun had already gone down and we could only see the outlines of the “pouches” in the twilight. (Some friends in Norman managed to shoot very nice mammatus pictures – hopefully some of them will let me link!)

I’ve since seen video of a solid stovepipe tornado in the Byars storm, definitely a more substantial one than either of the two tornadoes that showed up in my video. I speculate that the brief funnels that Dan D. and I witnessed may have been vortex arches being drawn up into the Byars storm’s updraft, resulting in a counter-rotating pair of vortices (something I found – twice – in my Ph.D. research on the 4 May 2007 Greensburg tornado). Fascinating stuff!

I’ll reveal upfront that we didn’t catch any tornadoes on Thursday. The atmosphere decided to skunk us at every turn, failing to produce tornadoes in our target storms, then proceeding to spawn tornadoes minutes after we bailed for other targets.

The day started out with great anticipation. A negatively-tilted trough, along with other favorable ingredients, had appeared in model runs for several consecutive days. Originally, the prospective target was the eastern Oklahoma-Kansas border, around Bartlesville. We’d already arranged a three-car caravan to go chasing, including several new/guest chasers, thinking the odds were pretty good that we could bag them a first tornado.

About 24 hours before chase time, it became clear that the trough was digging farther south than originally thought, so we shifted our target south into eastern Oklahoma, where SPC had delineated a moderate risk area with extensive discussion about favorable conditions for supercells all along the dryline. Concerns about lack of low-level moisture return were allayed by mid-60s dewpoints spread across eastern Oklahoma (as seen by the Mesonet) on Thursday morning, and a strong signal appeared in both the NSSL WRF and HRRR models for isolated supercellular convection in eastern Oklahoma, south of I-40. In the meantime, the warm sector north of the Kansas border looked more and more like an uncapped mess, so we decided to eliminate it from our target.

Our caravan departed Norman just after lunchtime, stopping along I-40 north of Seminole as convective towers began to bubble all along the dryline. The “tail-end Charlie” storm near Atoka, OK, about 60 miles to our south, quickly became dominant. However, we were reluctant to blast south after it, because it would have meant committing to a storm that would certainly move into difficult, forested, hilly terrain, while further eliminating the northeast quadrant of Oklahoma from our target area, where other storms with wall cloud and funnel cloud reports were already occurring.

We decided to wait for a cell that developed immediately to our southwest. For a while, it seemed like a good choice. This “middle” storm gradually gained strength and assumed supercell shape on radar. It had good separation from the storms to its south, which raised our hopes for uncontaminated inflow. However, I noticed that just about every blip on the KTLX radar had a supercell shape to it – an indication that the local atmosphere was almost uncapped, that convection was likely to fire up everywhere around us, and that outflow boundary and storm-storm interaction might prevent a single storm from becoming dominant. We decided to sit tight, preach patience, and wait for our nearest cluster of storms to get its act together.

When one storm in our cluster finally did become dominant, we proceeded to chase it north of Seminole, then abandoned it as it gusted out and another cell to its southwest began to grow. Of course, just a few minutes after we departed our original target storm, GR3 flashed a tornado report from a credible chaser underneath it. D’oh! We watched our second target storm produce and dissipate a couple of wall clouds, then decided to race east on I-40 after our original target storm, now located over Okemah, OK. We easily caught up with it again, and watched for a few minutes as it, too, generated and dissipated a wall cloud with a clear slot, but refused to complete the display and produce a tornado.

As we zigzagged north and east through Morris, OK, nickel-sized hail pelted our caravan. It didn’t make us feel much better that the Atoka storm, well out of our reach to the south, was leaving a trail of tornado reports in its wake. As we passed the wind profiler station near Haskell, OK, its measured wind profiles indicated a weakness in the hodograph between 1 and 3 km above the surface – a possible clue as to why these storms seemed almost incapable of generating persistent low-level rotation. We eventually called off the chase after dark, just north of the town of Wagoner, east of Tulsa. We were treated to some spectacular ground-to-cloud lightning, a consolation prize of sorts, on the drive home.

Yesterday stung more than I expected it to. It was a day that reminds me how much I still have to learn about storms. A group of experienced chasers made near-unanimous decisions that probably would have paid off in most situations. In the end, our decision to avoid the difficult terrain east of Ardmore probably cost us a glimpse of the Tushka tornado, but at the same time, I know of some people who did commit to that storm and still didn’t see a thing, thanks to trees (both standing and fallen), and the notorious terrain that compelled VORTEX2’s organizers to cut a chunk of SE OK out of their operating domain. But, no guts, no glory.

For those who are curious what we missed, I’ll link to this video shot by our friend Gabe G. and his chase partners.

Unfortunately, this tornado caused two fatalities, numerous injuries, and extensive damage in Tushka, OK. In light of that, our bust chase seems pretty trivial.

To their credit, our guest chasers were all very good sports about the situation. A couple of them can’t wait for another chance to chase, and it looks like there are, indeed, other opportunities peeking over the horizon.

I started out my Saturday at a meeting of the local Norman ham radio club (W5NOR), where I was invited to give a talk about my Ph.D. research on the 2007 Greensburg storm and tornado. By the end of the day, I’d be watching yet another supercell track near Greensburg.

Dan D. and I briefly considered making the long drive up to Iowa, where were convinced a significant severe weather outbreak was going to occur. However, we were reluctant to shoulder the fuel expense (gas is now approaching $3.75/gallon, even in central Oklahoma) and the long drives there and back, so we looked to more local targets.

I was not terribly impressed with any of the high-res WRF and HRRR solutions for 9 April over Oklahoma and Kansas, which consistently showed brief, disorganized bursts of convection, primarily at and after sunset. However, we joined a three-car caravan (including former officemates Jeff S. and Jana H.) and headed up toward Wichita. We spotted some wind damage near Blackwell, OK, caused by outflow from a supercell that crossed I-35 near sunset the day before.

Discouraged by the clear blue skies surrounding us, we held up briefly just north of Wichita, KS, then again in Kingman, KS. As 00Z approached, I was not optimistic. We had a number of “guest” chasers in our caravan, so we decided to target an anemic-looking blip that appeared near Woodward, OK. Haze prevented a good view of the associated cumulus towers until the sun dipped down behind it. I was encouraged that the updraft was substantial enough to completely block the sun, and the reflectivity values in the core continued to increase with time.

As we approached the storm along U.S. Hwy. 50/400 (which is vastly improved after years of construction, by the way), it took on a more supercellular appearance on KDDC. Interestingly, the storm’s motion was that of a left-mover (racing northeast at 55 mph), and a notch and mesoanticyclone developed on the storm’s northern flank. As the sun finally set at 8:04 p.m. CDT, we also saw hints of a hook and mesocyclone on the storm’s southern flank. The storm had a split personality!

North of Pratt, we passed an area of wildfire damage, with some stumps and trees still smoldering orange in the twilight. (Didn’t get any pictures of this, unfortunately.) The storm continued to race away to the northeast. Its base appeared to be well over 1 km AGL, a result of the 25-to-30 degree F temperature-dewpoint spreads being analyzed in the area. We stopped to watch the storm move away into the gathering darkness, then called the chase off. As we headed back to Pratt to get food, we managed to raise Amos M., who was chasing a few miles away from us, on amateur radio, and convinced him to join us for dinner at Playa Azul. We hadn’t seen him since the previous chase season, and it was good to catch up. Afterward, he joined our caravan as we headed back down I-35. We made it back to Norman around 2 a.m.

Along the way, reports surged in of the tornado outbreak in Iowa, including extensive damage in Mapleton. Even though I didn’t see a tornado on a day when so many others did, I don’t feel any great regret over our choice of target. We saw a photogenic supercell that exhibited interesting behavior, and didn’t have to stray that far from home to do it.