The last week of April saw the arrival of this year’s Windom High School group from southwest Minnesota, consisting of nine enthusiastic, weather-savvy seniors, their teacher, Craig Wolter, and three chaperones. Each year, Craig takes his top ten or so students on a five-day storm chasing trip to Norman, where the students get to visit the NWC and meet and greet with meteorologists there. Craig has a tight itinerary for his students upon arriving in Norman, but it can always be pre-empted by a decent chase setup. As a fellow Minnesotan, I have a soft spot for Craig’s kids, and always try to lead them on at least one chase. If there had been such a program at my high school, I would have killed to get on the trip!

Dan and I were able to take Windom group out on Monday, April 30th, after noticing an enticing setup in the Texas panhandle consisting of a trough encroaching on an outflow boundary from the previous night’s widespread convection. Upon arriving in Memphis, TX, we found convection struggling to initiate along the dryline. We drifted northwest on U.S. Hwy. 287, toward a clump of storms west of Amarillo, intercepting it as it organized into a supercell near Claude, TX. We drove about 2 miles north off of U.S. Hwy. 287 to obtain a clear view to the west.

We were presented with a beautiful, high-contrast LP supercell, and proceeded to point out all the salient features to the students. The high bases didn’t bother us too much, because we knew the Claude storm was drifting east into better moisture, and we expected great things from it once it began to realize the improved buoyancy. As we watched, the Claude storm split right in front of the students, allowing us to narrate the process live. I pointed out a small, cone-shaped lowering just south of the main precipitation shaft on the right-mover. It persisted for three to four minutes, but never extended more than 10% of the distance from cloud to ground.

Meanwhile, we noticed new Cbs to our east, rooted in the deeper moisture. The updrafts on the new towers were crisp and glaciated, so we kept our heads on swivels in case we needed to re-target. The Claude storm dropped a few nickel-and-dime hailstones on us, forcing us to jog east twice along our dirt road in order to keep ahead of the storm. The vault structure grew breathtaking. We were able to enjoy it in relative solitude, without any other chasers blowing clouds of dirt on us. Simply moving a mile or so off the main highway is proving a surprisingly effective way to avoid the hordes. (I think I’m going to require 4WD in my next chase vehicle.)

The Claude, TX supercell eventually became outflow-dominant, so we decided to re-target the next storm to the east (the Hedley, TX storm), whose birth we had witnessed about an hour before. We retraced our route southeast on U.S. Hwy. 287, then went east on TX-203. We thought we would be able to core-punch the Hedley storm without too much trouble as it lifted northeast, then emerge from its forward flank and with a view of the hook to our southwest. However, radar updates showed new storm cells erupting to the south of, then being ingested by, the Hedley storm. These processes interfered with storm consolidation and hook formation, and also resulted in our spending more time in the hail core than we expected, our vehicles pelted with nickels and dimes for nearly 40 minutes.

When we finally did emerge from what should have been the forward flank of our target storm, crossing over the border where TX-203 changed to OK-9, it was dusk. Looking back toward Wellington, TX, we caught glimpses of the hook region to our southwest. Suddenly, Dan commanded me to stop the car, chattering excitedly about a dust cloud. I couldn’t see anything from the driver’s seat, but I stopped at the top of a hill. By the time I got out of the car and fired up my camera, the dust cloud was gone, but I could see the scud finger which had grabbed his attention. My only photo of it is very poor and I had to enhance the hell out of the contrast in order to make it visible. The feature was too brief and ambiguous, the distance too far, and the lighting too poor, for us to conclusively call it a tornado.

We took a rather circuitous route back to Norman via Lawton, attempting to avoid a southward-diving hailer over Hobart, OK. We returned to Norman around 1 a.m.

In the days since this chase, I’ve read an April 30 chase account from Bill Reid, whose Tempest Tour group (including Brian Morganti) was much closer to the ambiguous lowering than we were. Even with his close proximity, he wasn’t certain what to call the feature, and after viewing his video, I can see why. However, he eventually concluded that this dusty spin-up was indeed a tornado. Bill’s a veteran chaser, and if he says it was a tornado, then that’s good enough for me. Based on his account, I was able to report to Craig that his students were no longer tornado virgins!

Update, 2012-05-07: After looking at video from the Tempest Tours group, the NWS office in Amarillo declared our “scud finger” an EF-0 tornado. So, now, it’s officially official!

Parental visits in springtime are always fraught with uncertainty. We can pack our agenda for the weekend with varied activities, only to have everything unravel the minute the atmosphere starts acting up. I had poo-poohed the chase setup for Friday, April 27th, thinking that it wouldn’t be worth driving to Kansas. However, I awoke to find the forums abuzz with excitement about the shortwave trough ejecting earlier than forecast, prompting a moderate risk on the Day 1 convective outlook from SPC. Anticipating an early afternoon chase setup, my husband and I scooped my parents up from the airport, and blasted north on I-35 into south-central Kansas, where we were greeted by clearing skies and a few turkey towers along the dryline. (Mom and Dad had flown more than 800 miles south from Minnesota to see us, only to backtrack immediately almost 1/3 of the way home.)

Near Emporia, KS, we met up with Jeff S., chasing solo. The atmosphere produced mediocre convection for hours. As a surface low approached from the west, increasing the low-level shear, it also squeezed the warm sector between the cold and warm fronts. We were forced to follow the warm air up into the Flint Hills area. This region has good visibility, provided that you’re on top of one of the hills. By the time we targeted a storm near Council Grove, KS, the warm sector (and the storm’s access to the warm, moist air within) was only a few tens of miles wide, if that. Cold rain and gusts of wind pelted us as we parked on a hilltop gravel road off U.S. Hwy. 56 near Bushong, KS, watching two cloud bases to our west-northwest. Suddenly, Jeff S. shouted to our group as a small white funnel abruptly materialized within an RFD slot to our northwest. I barely had time to re-center my video before it eroded away.

Minutes later, another funnel descended from the far bank of clouds, tickling the ground with a few suction vorticies. From my vantage point, this brief tornado dropped right behind a tree. My video consists mainly of my scrambling a few feet to the right and re-leveling my shot, by which time the tornado had already vanished. Because of the brevity of these two funnels and the shakiness of my video, I decided not to post either shot on YouTube. Screen shots it shall be.

The cold rain and pea-sized hail began to fall in earnest, driving us back into our cars. We may have glimpsed another funnel on the horizon, but lost it in the rain after a few seconds. To our north was a road hole, forcing us to head east on U.S. Hwy. 56. The remainder of our chase consisted of an attempt to catch another storm to the east of our original target. Unfortunately, it was ingesting stable air, the warm sector long since squeezed out of existence, and we decided to abandon the chase near Osage City, KS. We had dinner at Emporia, then began the long haul back to Norman.

As I’ve gotten older, I’ve gotten little more choosy about which days I chase. (I chalk part of this change up to accumulated experience, and part to having a full-time job and family to support now that I’m done with school.) However, when I have guests along, I’m more likely to bite on riskier setups with more potential failure modes. Even though it required a 5-hour drive each way, seeing one tornado is definitely better than seeing none!