June 25th, 2018 Mount Ayr, IA Brief Tornado
Tornadoes: 1
Highest Wind Gust: ~30 mph
Largest Hail: N/A
At this point in the year, my chase season was essentially done. I might still be able to chase if I was lucky enough for a setup to fall on a day off work, but my availability no longer supported chasing 95% of the time I wanted to. I was working 6 days a week in the afternoon with no one to cover me for a few weeks. That one day off was Monday. Much to my surprise and dismay, two consecutive chase days in the Midwest looked to occur, one on Monday (June 25) and the other on Tuesday (June 26) when I would be forced to go back to work. Monday showed potential in Iowa, Tuesday in Illinois. I'd have to miss chasing my backyard, which I knew was going to hurt, so I wanted to make the most of the system when I was able to chase on Monday. A somewhat dynamic setup, at least in the low levels, with an occluding low pushing through the Missouri River Valley with decent shortwave impulse accompanying it in the mid-to-upper levels. The low level jet, however, was forecast to be screaming from the south to southeast with surface winds backed in the vicinity of the warm front. The major caveat was that there was much uncertainty regarding destabilization as a shield of rain and embedded thunder was expected to move through central and eastern Iowa through at least mid-morning. Given the time of year with high sun angle, I was willing to bet on quick destabilization even if clouds lingered longer than was optimal.
I chased with Matt Zuro, Daniela Barrios, and Isaac Polanski with an initial target near Des Moines.
500 mb winds:
In the morning, destabilization was still very much in question, but we were still willing to take the gamble as there wasn't really much more uncertainty than the night before. We stopped off at the Iowa 80 truck stop to get gas, where we had a bit of a conundrum over what to do. I still wanted to keep going toward the target area, with the destabilization question still up in the air, but the others wanted to turn around and head back home. We were all piled into my vehicle, so it wasn't like some of us could head back home and others keep heading west. I was able to convince them to continue toward the target, and if at some point it became clear that there wouldn't be enough instability, we'd turn around. We had one more debate over this at a rest stop, but I saw no reason to call off the chase with short term models and satellite data now trending toward a solution with sufficient CAPE. We got to Des Moines and started down I-35, rain tapering and skies brightening as skies began to clear across southwest into south-central Iowa. Instability was starting to work its way in:
We found a spot on a back gravel road just north of the Iowa/Missouri border west of I-35 to wait for initiation. There were railroad tracks near where we stopped, and Matt and Isaac explored them for a while as I sat in the car with Daniela looking at satellite and mesoanalysis. Agitated to towering cumulus was beginning to form near the cold front north of Kansas City, and we started to pay stronger attention. A band of weak storms developed along an arc across the border into Missouri, and were moving towards us in south-central Iowa. Still, we began to move toward them, wanting to make sure they didn't do anything early on.
Making it down to the town of Mount Ayr, we turned south down a reliable highway to gain a visual on any one of the updraft bases in the closely packed line of quasi-supercell structures. We did catch a generally low contrast visual of a monotone-gray scuddy base:
Although it wasn't the most incredible or promising storm structure I've ever seen, it was surprisingly better than I'd expected given radar presentation. This cell was in between two others that looked to have similar potential. There was a more pronounced bowl lowering becoming apparent:
The storm to the south very soon after went tornado warned. The warning text mentioned a confirmed tornado, and we were somewhat defeated having missed it, but also somewhat encouraged that environment might actually support tornadoes. Our storm maintained its structure, rising motion gradually strengthening. A pronounced wall cloud started to pick up in rotation as RFD began to wrap around the circulation. Our storm now gained a tornado warning:
Rotation kept getting faster, eventually to the point where we expected a funnel to drop at any moment. A small funnel dipped down briefly as tornadic motion was now present at the cloud base. Rain curtains were flying left to right in front of it, and we began to speculate that this might be a weak tornado in progress. We couldn't tell for sure, but there may have been small, brief vortices visible from our vantage point. Although we weren't certain at the time, someone much closer tweeted that debris was being lofted and it was indeed a tornado.
Still image of the tornado:
When I heard the news, I was ecstatic. FINALLY a tornado in 2018! I didn't care if it was a brief, weak little thing no one else would be impressed with, I was just excited to not be tornadoless this year. My streak of years with a tornado witnessed would continue.
Video:
Notice that even though it never condensed, motion was rapid at the cloud base. It wasn't the absolute most pathetic tornado I've seen for that fact only.
The circulation became completely rain-wrapped as we attempted to drive further down the gravel road we were pulled off on to get closer. The road dead-ended, so we were forced to turn around back to the highway to follow the storm north. We turned west when we made it to Mount Ayr again to catch it as it crossed the east-west highway. The meso was occluding and most of the motion was gone after we pushed through the rain to get a better look. There was a fairly "neat" looking wall cloud left behind:
Our storm was falling apart, but the cell to the south was intensifying again as it moved NNE. We pressed back to Mount Ayr once again, where we took a different paved road south out of town to try and meet it. We caught the surprisingly organized updraft base as we emerged from the core south of town. I didn't get any documentation of it, unfortunately. The biggest trouble with positioning was that there wasn't another east/west paved road for several miles, and we had to drive well past the base to get to it. There was a good grid of very hilly, wet gravel roads, but the inclines with at-times slick road surface weren't worth it to us, and would slow us down even more. Base well to our north now, we turned east onto our paved option and raced for the next paved north option, which was also quite a distance away. Our only hope now seemed to be the sketchier unpaved roads we refused to use earlier. We found one that led straight up to the east/west highway out of Mount Ayr (which we should've used in the first place), and took it. There were a couple of scares as we crested many large, steep hills, but we made it without a problem. We made up some ground on the storm to discover that it had largely gone shelfy with little in the way of a focused updraft region. What we did note, however, that there was a rapidly rotating anticyclonic wall cloud on the south end of the RFD, just north of the road behind us. Of course, I didn't get any documentation of this, either. It gradually petered out after a few minutes.
The storm now looking lackluster after we turned onto a side road, we decided to call it a chase. A big shelf cloud was fanning out, signalling a big, broad outflow dominant storm:
A car pulled up as we stood there watching the decaying structure. It turned out to be Joey Marino, who I'd talked to a little bit on Twitter, and I knew was good friends with a chase partner of mine, Matt Magiera. We had a good chat for over an hour on the random southwest Iowa back road as storms pushed overhead and then to our east. It was a blast and the time flew by. Always great to meet new people out there on the chase.
All of us headed to a gas station not too far away off I-35 near Osceola, IA where we got gas, then parted opposite ways down the interstate for our 5 hour drive home.
This year has been terrible, but as I stated above, I wasn't tornadoless. I know a lot of chasers will crucify me for saying this, but a dinky tornado is as good if not a better prize than most good structure. There's something about tornadogenesis that will never get old to me, no matter how underwhelming. Obviously these aren't the most incredible tornado intercepts, but they are still special to me.
SPC Storm Reports:
One lone red dot (okay two, but they're so close that they look like one). I'd say we did well for what little we had to work with.
GPS Location History:
