June 2024 Storm Chasing Recap

Despite marginal instability and weak upper-level support, surface and upper lows spinning over the St. Louis metro meant this would be a day to go out and track any storms that managed to form. I went out and made several back-and-forth treks in the eastern metro area covering multiple rounds of storms from Okawville to Marine, through Trenton, Albers, Lebanon, Damiansville and St. Jacob. The storms displayed interesting structure at times, and I observed broad rotation near New Baden at one point - but no tornadoes, funnels or even lightning/thunder were noted. There were plenty of tornado look-alikes.

A line of storms had been shown by models to pass by to our north during the early afternoon. Despite a shortwave trough passing over, instability was weak. I worked a string of late nights this week, and I didn't think this event looked good enough to take PTO and sacrifice sleep to cover. That being said, I did wake up a few times to look at radar. The expected storms developed as models showed, but were a little stronger and extended in a line a little farther south than forecast. The closest lightning strikes were only about 20 miles to the north, so I went out for about 10 minutes north of town to see if the line would develop any farther south near home. They didn't, and since low clouds blocked the view of the weakening storms to the north, there wasn't anything photogenic worth staying out for.

A strong convective complex in Kansas and Nebrasks had been shown by models to outrun the instability long before reaching the St. Louis metro on Saturday morning, with only a stratiform rain shield passing over. The line of storms attached to this area seemed to be holding on long enough that there was a chance for upward lightning to happen in St. Louis at daybreak, so I went down to Mehlville to await that possibility. The electified portion of the stratiform area only made it to Union, Missouri before fizzling out. One distant flash of lightning to the south was the only thing I saw before heading home at sunrise.

This had originally been expected to be a big day for either the St. Louis metro area or just south of it as supercells developed on an outflow boundary in the evening. However, as the previous night's convective complex moved across Missouri and weakened (see my previous entry), it became apparent that the outflow would push much farther south and leave us mostly high and dry for evening/after dark storms. I didn't leave home until 8:30pm, and it was just to go a couple of miles south of town to see if any lightning was visible with a small cluster of storms that had fired down near Marissa. There were some distant CGs and a few visible negative-leader "anvil crawlers", but stratus moving northward quickly blocked the view as the storms weakened. These two were the best I saw.

I had been watching this day for a week prior, as models were in good agreement for a shortwave upper trough to pass over the Plains with good moisture in place. It appeared to be the last decent setup of the season south of the Nebraska-South Dakota border, and since it was on a Saturday, it would not require any PTO to cover. As the event drew to within a day, I was still undecided on whether it would be worth the 7-hour drive (each way). It did not appear to be a "slam dunk" for tornadoes: a strong cap, the wave arriving/departing early, morning storms potentially fouling the target and messy storm modes were all concerns. On Saturday morning, I woke up early to look at things, and was not impressed with what I saw. A large complex of storms was hanging on just south of the primary target area, and thick cloud cover extended to the north across that region. Models were also not robust on tornadic supercells within the range I could fit into an out-and-back day trip. After considering all of that, I made the no-go call by mid-morning.

Just before noon, I took another look at the visible satellite imagery to see the outflow boundary from the morning storms had pushed south of Kansas City, and had cumulus bubbling up along and south of it as the skies cleared. It was a classic satellite signature that is a beacon for a storm chaser. The boundary in that region was also oriented more east-west, which would allow a northeastward-moving storm that was able to track along it to have good deviant motion/storm-relative helicity into the southeasterly surface winds. Wind profiles along the boundary looked great for supercells, with the upper level flow from the shortwave still overhead through the evening. Models were not very optimistic that a storm would sustain in that area, but if one did, it would likely produce a tornado. With this target less than 4 hours away and within easy range of a day trip, I decided it was worth going to take a look at it. Farther north into Nebraska, the parameters looked good for tornadoes also, but concerns about storm mode remained - and I really wasn't feeling up to that longer drive that would likely require an overnight stay somewhere afterward.

I left home at noon. I was pleasantly surprised to see relatively low daytime traffic levels on the normally-maddening I-70 across Missouri. Two storms fired over the northeast side of the Kansas City metro at 2pm, at about the time I was passing through Columbia. I went northeast toward these at Auville. The storms dried up as their updrafts vanished, leaving an "orphan anvil". An orphan anvil is a failed thunderstorm in which the initial updraft makes it to anvil level, then dries up to leave nothing but the anvil itself. A new updraft began taking shape near Lexington, so I stopped on the north side of the Missouri River to watch it approach.

This too suffered the same fate as the first storms, squashed by the strong cap. Another updraft near Richmond made another attempt at a storm, but it too was cut off by the cap. This sequence of stills of this last one shows how the orphan anvil forms after the original updraft tower dries up. Many times, these will still have radar echoes that make it look like a storm is still present. If the updraft is gone, the storm is too - and the radar echo will eventually fade as well.

It wasn't long before I started seeing the tornado reports (decent ones at that) from northeastern Nebraska in an area that was even farther away than what I'd been looking at originally, one which would have required a 9-hour one-way trip. It's doubtful I would have been up to going that far even if I'd chosen to go to Nebraska. As my cumulus field near Kansas City continued fading, I called the chase at 6PM and started the drive home.