May 18, 2021

From my morning email forecast discussion with the group:

"Multiple low confidence targets:

Target A: Local play off the dryline. Scattered thunderstorms possible along the dryline from nw of Lubbock to s of Odessa. Instability axis looks narrow with a sweet spot gradient of clearing to the west and either capped or worked over air to the east. Storms may not survive terribly long in this, but perhaps enough time to organize supercell structures and squeak something off as they die to the east.

Target B: Junction of the trailing MCS outflow boundary, the warm sector of S TX, and orographic features in Mexico from Del Rio northwest along the highway 90 corridor. Hints at lone supercell initiation here. CAMs hit or miss on this target so a conditional gamble depending on what the MCS does. Better midlevel flow here to sustain supercell structures, but not seeing much on low level shear unless there's boundary influence. Terrain and road options may preclude a research case intercept. Interesting that the storm is not maintained on the HRRR down there, maybe capping problems or lack of lift once the storm is off the initiation terrain feature.

Target C: S and near AMA in the residual left over airmass from yesterday. HRRR currently progs an MCS shortly from the activity to the west in NM and impact the area, but there may be some cells in play on southern periphery. Cooler temps and modest instability suggest small, grey cells.

Target D: A cold core play in the OK PH far N TX PH. A conditional crapshoot. Area will likely be socked in with ongoing convection, but cold temps aloft with a closed 500 mb low spinning away to the west, and the warm front sitting near the OK/KS border may yield low level instability and strong low level wind shear. It might be a needle in a haystack to a find a tornado up there and they will likely be small grey wisps from low bases.

Leaning on target A just for logistics reasons, but would welcome meteorological opinions that sway decision. HRRR is consistently firing Seminole, TX again. I'm inclined to believe when there's run to run consistency, and also based off of my superstitions that we chased there yesterday, and leaving there for another target will surely result in a missed tornado. Options north present an intriguing sneaky play, but the Day 2 looks like it's around this area anyway."

Our second day of the season with the full team had us positioned down the road from Brownfield as high based storms popped to our southwest by early afternoon.

We played with drones and snakes in an empty patch while waiting for storms to organize.

From my Facebook post about the day:

"I always thought the weather was governed by the equations of physics, that naturalism prevailed and not supernatural forces. So we’re south of Lubbock on a lackluster setup, under sheared, outside the 2% tornado line, not expecting much beyond some high based showers. Pecos Hank gazed at the mundane updraft base drifting across the Texas Caprock. He disappeared into the brush, and there he summoned a serpent. Returning with the snake, he held it to the sky and began the incantations. And with that the storm began to spin. Eddies of dust twirled like mad on the ground. The clouds churned aloft making big spirals and small funnels that dipped below the clouds. Then I knew it was actually black magic that conjures the evil vortex spirits.

May 18, 2021 southeast of Wellman, TX: We were under the north end of the horseshoe shaped bowing supercell updraft base. Surges of outflow kicking up large dust plumes with multiple gustnadoes had been ongoing. There was fairly tight yet not very strong cyclonic rotation overhead in the storm’s base. A gustnado spun up nearby, but it was moving against the mean outflow direction, riding the inflow interface toward the storm. It persisted for a couple minutes, and started to hook left like an infalling satellite around the rotation overhead as it tightened up a bit. It probably looked like every other gustnado from further back, but I’ve seen this sequence a couple times on developing tornadoes, one of which we were impacted by in 2015 while chasing with TIV. It’s like vorticity aggregation into the pre-tornado vortex, or maybe a gustnado-tornado hybrid where a gustnado migrates under the main mesocyclone updraft and comes under its influence. Probably a few degrees of dew or knots of shear from a more robust tornadogenesis, but it looks like the storm tried it a couple more times, spinning up a pretty legit funnel on the last attempt."

We moved in closer to the storm, just north of the updraft base. Looking south, there was lots of gustnado activity on the RFD gust front:

One of the gustnadoes was moving in the opposite direction, however, westward toward the storm. We noted cyclonic rotation aloft, and I suspected it was a subvortex scale circulation in the pre-tornado vortex of a tornadogenesis attempt. As noted in my account above, I've seen this scenario before on developing tornadoes, which caused me to prematurely hit the button on a tornado report. Maybe it was just a gustnado on a retrograde portion of the gust front. The feature didn't develop any further, and the surface vortex was probably no more intense than any of the other gustnadoes in the area, so didn't really warrant a warning, even if the storm was going through some of the early stages of tornadogenesis. It still appeared way too high based to be a robust tornado producer.

We zig zagged to keep going east on the diagonal Texas road grid. A rear flank downdraft cut into the updraft base, but it still looked too high to me.

However, the base wrapped up, the occluded updraft within spinning up a well formed nub funnel cloud.

We were positioned well north of the updraft and scrambled to get downstream for a possible team deployment on a developing tornado.

We didn’t have a great paved option to get immediately in front of the storm, so we wound up tracking east a ways. A small block wall cloud developed and then a slender point funnel cloud.

We were way too far for a good photogrammetry shot, but the funnel only lasted a couple minutes anyway. It was probably the rope-out stage of the original nub funnel, attempting to condense in its dying stage as the vortex tightened. The feature was reported as a tornado by closer chasers who noted another gustnado sized dust whirl beneath the funnel.

Wide shot of the whole storm and wall cloud remnants:

The storm gusted out so we transitioned from a tornado chase into a structure chase, running well east through the Texas scrubland to get downstream for longer and wider shots.

I setup for time lapse, Brindley shot lightning on a trigger, and Hank flew his drone over the group. It was a gorgeous end to a well-rounded and rewarding chase.