May 31, 2018

Thursday, May 31 wasn't forecast to be a particularly big event in the Northern Plains, but we were already out on an extended chase trip. I had picked up Brindley the day before in Minnesota, and we met up with Phil Bates who flew into Rapid City. Our plan was to get cells between Dickinson and Bismarck, North Dakota at or close to initiation while they remained discrete as a transition to an MCS was expected. We made the trek north from Rapid City arriving in Dickinson by early afternoon to see storms already maturing and sailing east in the relatively fast zonal flow aloft.

A short east west line of supercells developed and we ran east down I-94 for the intercept, but had trouble keeping up. The eastern most cells looked like they were struggling against capped air or were overrunning the instability axis. We doubled backed to a more robust north south line of storms that was developing, expecting to shoot some shelf cloud structure. A kink in the line north of the highway picked up a tornado warning, however, and we were in full intercept mode.

The line looked super omininous and we were reluctant to get right into the notch near the town of Hebron, so we stayed just to the south, looking for a view among the rolling hills. A rain wrapped tornado was reported by chasers, but we couldn't see much to our north.

We ran east down 94 again to stay ahead of the line, and again storms looked like they were struggling in the airmass to the east. The updraft bases were retreating and becoming higher and higher. The flat textured undersides of the storms were pretty against the North Dakota landscape, but our chances at decent supercell structure were fading, let alone a tornado, which we weren't even thinking about anymore.

We dropped south to catch more robust cells as they approached from the west, expecting those too would soon fizzle. Heading down a pretty red gravel road, we topped a hill and the view to the west opened up spectacularly, revealing rolling green hills and a turquoise stormscape with white cloud layers. Chaser Shane Ornelas had already found the perch. We all got out and watched a detached roll cloud push east away from the storm and move overhead.

Phil Bates setup his Red camera again, capturing this cene. The white roll cloud was gorgeous against the blue and turquoise North Dakota sky. Something unusual started to happen, however. The forward motion of the roll cloud slowed and halted. Then the northern end of it seemed to grow, curl back into and connect to the elevated storm base, as if it was rooting to the storm's updraft.

Then the rooted end slowly began to rotate. We all watched the motion and transformation of storm structure transfixed.

The now connected lowering began to rotate faster and faster. I was reluctant to actually say it out loud for fear of jinxing it or being overdramatic, but the motion reminded me of a tornadic storm. I had never seen such morphology, and watched mesmerized. It looked as if what had once been the disconnected gust front of a supercell's QLCS-like flanking line, was pulled back and ingested into the storm's updraft. The northern end of the gustfront was now developing into a QLCS mesovortex, a shallower storm scale area of rotation that usually develops on the leading edge of a line of storms, rather than the deep and sustained mesocyclone of a supercell that forms on the storm's rear flank.

Phil captured this wide angle shot of the rotating lowering. A north moving blast of outflow kicked up a plume of dust on the ground while the lowering spun aloft.

Moments after the dusty surge of outflow, a small, tight vortex spun up in the field less than a mile to our west southwest.

It looked like a gustnado at first, but the vortex grew in size and remained fixed in position relative to the rotating lowering aloft, not tracking with a surge of outflow like you'd expect with a gustnado. It became apparent quite quickly that it was a tornado.

The dusty little tornado churned in the field. Phil and Brindley scrambled to shoot it, while I jumped on Spotter Network to report it.

The ground circulation started to widen and become diffuse. It was tracking more or less our way, and while I wanted to stay and shoot the both dramatic and gorgeous scene, we were in the path of a developing tornado and would have to move.

The main vortex looked like it was both widening and breaking down. Just to the right, a tiny yet intense subvortex like feature spun up.

Phil's Red captured the whole scene. You can see the corkscrewing spiral of the mesovortex aloft, and the tiny yet focused vortex parked on the ground underneath. The tornadic structure was located on the lead edge of the cell. The rather disorganized forward flank precipitation core and elevated looking updrafts of the rest of tyhe complex can be seen in the background.

A couple of small point funnel clouds spun-up under the base of the mesovortex feature while the circulations at ground level persisted. It looked like the vortex was moving to the left of our position, but the mesovortex aloft was moving overhead and the dusty ground circulation continued to expand. I told Phil to pack up his Red camera. We had to move.

While Brindley and I tracked the storm and debated our next move, Phil had meanwhile switched to shooting on his iPhone. This was the last known of sighting of it that day. We turned around and left the spot, exhilarated by what we had just witnessed.

We headed east back to the north south paved road. The tornado and mesovortex looked like they had dissipated, but a small funnel or two continued to appear amid the gust front mass ahead of us. I again sent a report of the rotation via Spotter Network. I could clearly see how the feature had formed on the radar, the gust front was apparent on the velocity scan. The nothern end of it curled back to the west with a small couplet. The weather service was quiet on issuing a tornado warning, and our tornado report apparently did not make the logs, however. The storm's gust front was ahead of us now as it fanned out to the east. The plan was drop down to 94 and head east to get ahead of it. That's when Phil announced that he had lost his phone somewhere. I was hoping that it had just fallen in the car somewhere, and didn't want to give up our position on a storm that had produced a tornado, but I agreed we could go back down the road and take a quick look in case he had dropped it ouside.

We were deep in the precipitiation core by the time we got there. Rain blew sideways across the road reducing visibility substantially. Phil made a vain dash outside into the stinging rain and small hail to look for the phone, but quickly ran back to the car. There was just no way to find it in those conditions.

Back on pavement, we could see off to our northeast the lowering from which our tornado originated continued to persist. There was some rising motion but no longer the pronounced rotation.

We tracked east with the storm for awhile until it lined out and filled in with rain.

Afterwards, we dropped south down a meandering gravel road and decided to do some longer time lapse shots of the storm's gust front. Multiple surges of outflow kicked up large plumes of dust and ejected lines of scud. We finally called it as the light started to dwindle, and made for Bismarck for the night. Phil's phone was still MIA.

Over breakfast at the hotel the next morning, Phil announced that his Phone was still alive, and pinging its location from the gravel road on which we shot the tiny tornado. Our route for the day conveniently took us back west right past the spot. We homed in on the location using our GPS log and the pings from Phil's iPhone app.

We crested the hill, and there it was, face down in the gravel. The IPhone had tire tracks on it, but the screen was intact and the phone seemed to be in fine working order. It had survived being run over by both a vehicle and a tornadic thunderstorm.