May 17, 2019

From my morning forecast email:

“Worried that the NAM has been overdoing moisture a bit as it has on previous setups this year. That's going to make capping and low level thermodynamics more of a problem for getting a tornado. Earl's lid strength, which I live and die by, is hinting that storms on the KS dryline will probably struggle with the thermodynamics a bit. CAMs do not show these storms persisting. Lid strength has the Panhandles pretty much shut down through 21z. It opens by 0z, but I'm worried it might be too little too late by then, with dryline mixing over and the dryline off the Caprock by then. These are subtle lifting mechanisms at work, and if we're missing a couple, or the cap is a little stronger, it could very well not happen down there..

Instead I think the lower risk gamble is to head up to Nebraska, northeast off the surface low along the warm front/stationary front. The cap opens before 21z there, moisture is forecast to flow along and pool on that boundary with upper 60s dews, and with the best 0-3km CAPE of all the targets. Directional shear is maximized on the boundary. I'm a little worried about storm mode here. A high precipitation storm is often favored on the warm front.

Points south along I-80 and even into northern Kansas look interesting. My goto tornado parameters look manageable here with decent LSI and 0-3km CAPE. I'm a little worried about temp/dewpoint spreads here with surface temps in the mid 80s shown on some runs and dews in the low 60s. A couple runs hinted at something like 77/63, which is pretty good for western Kansas. Still think this might be more of a gusty supercell play than tornado, but perhaps around sunset when that low level jet kicks in, you could get a nice show.

We're making for Broken Bow and that bowing warm front coming off the low. The warm front doesn't look too sharp at all on the HRRR like theNAM NEST was showing. Several supercells forecast on the NAM in thearea. Look for storms to fire in the Broken Bow area and southwest toward i-80 by mid afternoon, tracking northeast they'll mature and hopefully produce by early evening as they approach the boundary. The huge helicity tracks over the Nebraska Panhandle are almost certainly for elevated storms caught behind the boundary.”

Friday, May 17 was Brindley and my first chase together for the season. It was an exceptionally late start for us, already half way through the regular tornado season, but it looked like our first setup was going to be a big one followed by at least a week of active storm chase pattern. We left the night before the chase, and made our way down I-80 in Nebraska after stopping in St. Joe, MO for the night.

We stopped shy of North Platte, NE and got cameras and gear ready for the chase. The initial plan was to chase storms to the north as they came off the triple point and tracked to the warm front. By midafternoon our target failed to initiate, and it was apparent that we’d have to drop south for storms coming off the dryline out of Kansas instead.

Lots of chasers making the dash south with us:

A maturing supercell picked up a tornado warning as it moved from Kansas into Nebraska. We could see the anvil in the distance, but it felt like we were already missing the show.

We went south out of McCook and got our first view of the base. Hazy and distant, it wrapped up with a prominent funnel cloud. Our road was way too far east, and the storm was now pulling away to the north and our view disappearing in the murk. We had to head back through McCook and pick the storm up on the north side of town.

Tornado reports started coming in while we made the agonizingly slow trek down the main drag through McCook. The sirens wailed. Then on the west side of town, we could see it over the buildings. A large stovepipe tornado loomed in the distance.

We turned right onto 83 North out of town to catchup to the tornado and get clear of town. The sirens continued to blare as we got glimpses between the trees and buildings.

Finally clear of McCook, we could really see the tornado at last. A white tube churned up a huge brown dust cloud. The blue and tan gradients were gorgeous, the colors and thick atmosphere making the scene appear as if it were underwater.

We continued north, hoping to get closer, but wound up mainly paralleling the tornado as it moved on its mostly northerly course.

The funnel narrowed and contorted. The tornado was beginning to rope out.

We continued driving after it, Brindley shooting stills from the passenger seat while I had the camcorder on the windshield suction mount for video.

The tornado roped out like a twisting snake. It was a pretty incredible feeling to score our first tornado of the season right off the bat on our first day on the Plains together. The McCook tornado was rated EF2 and tracked west of town. We turned onto the unpaved road grid before we hit the forward flank, and began stair stepping east and north to keep up with the base.

We zig zagged on the grid for an hour before finally hitting highway 18 east out of Stockville, and that’s when the storm ramped up for another show. A classic wall cloud developed on the north rim of the huge horseshoe updraft base. We raced east down 18 to get ahead of it. A suspicious pointy lowering was jutting out of the rear flank gust front just south of the wall cloud. After a few moments it was obvious it was a funnel cloud, and then clearing some terrain we could see the plume of brown dust confirming the tornado.

A wide shot from the roof mounted GoPro looking north. It looked like there were multiple circulations in progress, the tornado on the right, a much broader area of rotation associated with the wall cloud in the center, and on the back of that a trailing funnel with weaker rotation.

We found an elevated pull off with a great view to the north. Unfortunately the tornado began to dissipate as soon as we stopped. The wall cloud looked like it was ramping up into a large tornado cyclone, however. Meanwhile, the anticyclonic southern end of the horseshoe updraft base was also rotating. The GoPro captured a small, brief point anticyclonic funnel in the center as the remnant dust from the Stockville tornado faded to the east. The tornado was rated EF2.

The “conga line” caught up to us and highway 18 was filled with eastbound storm chaser traffic. The tornado cyclone continued to intensify and it was getting away from us. We caught an opening in traffic behind the College of DuPage vans and gunned it east.

Brindley watched over my left shoulder to the north. “That’s going to produce”. A minute later a tornado developed as a big dusty debris cloud beneath the rotating wall cloud.

A large funnel took shape in the tornado cyclone. Even though it still hadn’t fully condensed, this tornado looked quite a bit more robust than the previous ones.

We turned north onto the unpaved road grid once we were even with the tornado. It churned up a massive brown debris cloud, obscuring the funnel. This is about when the EF3 peaked in size.

We stair stepped north and east on the unpaved road with several other chasers in front of us. Rain finally wet the road enough to keep the dust down from both the traffic and tornado and we could see the funnel once more. Our way north was blocked. Power lines were downed and draped across the road, irrigation equipment flipped, and up ahead a trailer had tipped over into the road. We turned east with the rest of the chasers.

The tornado started to fully condense into a beautiful white stovepipe, yet our road was squirrelly with hills and offered little in the way of views or safe pull-offs. We hurried along down the road looking for a good place to stop and watch, worried that we were going to miss the show. And then atop a hill, the view opened to the north with a flat grassy plain. We pulled off with a handful of other chasers. The tornado was just then widening into one of the most photogenic and classic looking ones I’ve ever seen.

Brindley jumped out to shoot the camera while I stayed inside tending the windshield mounted video camera in awe.

A howling south wind whipped past us into the vortex, rocking the car and making little bits of dust and grass fly.

The funnel started to narrow as it began to rope out.

The roping out funnel twisted, sweeping back and forth across the plains. The sight reminded me so much of the Wizard of Oz that I couldn't help but make a sepia toned edit to try and match the film.

Brindley was ecstatic with our catch. Unbeknownst to us, Hank Schyma was parked right to next to us, and you can hear Brindley in his video from the day. We’d wind up teaming up with Hank, and Anton and Tracie Seimon ten days later for our coordinated research mission.

After the tornado roped out, we filed into the “conga line” and started stair stepping again to get back to pavement. The going was slow due to ever increasing amounts of traffic and sporadic encounters with damage in the road.

We made it up to highway 23 and the town of Farnam finally. The storm continued to cycle and would likely produce more tornadoes, so we were eager to catch back up with it. East of town, however, the traffic came to a stop, and we could tell something up ahead had blocked the highway. We pulled a u-turn and headed back west through town, looking for another route up to I-80. The only options that weren’t dozens of miles out of the way were unpaved. We attempted one, but the sides of the road started to turn to pancake batter, and not wanting to slide off the road, we aborted the attempt and headed back to pavement. The storm was getting so far ahead of us that we likely wouldn’t be able to catch back up with it anyway. We drove back into Farnam, but realized the chase was pretty much over. Before heading up to North Platte for the night, we stopped and chatted with a few other chasers including Chuck Haskin, Carrie Svihlik, and Bill Hark.