Weather Flashback

November 2021 - Mangum Tornado (May 20, 2019)

Summary

I captured this scene from just west of Granite, Oklahoma, on the afternoon of May 20, 2019. In this scene, I am looking southwest at a tornado about 10 miles away "as the crow flies." This is the same tornado that impacted nearby Mangum at about the same time that I captured this scene. For most of central and western Oklahoma, this was a "High Risk" day for severe thunderstorm activity according to the Storm Prediction Center. Even though high-end severe thunderstorm activity was absent across eastern portions of the High Risk outlook area, the Center's forecast products that day reflected the [presumably] best information available. Best information in terms of severe storm predictive-ness. In other words, given the data available, the Center issued the best possible forecast products to account for the likelihood of high-end severe thunderstorm activity. This high likelihood covered a large portion of central and western Oklahoma, including Norman and the campus of The University of Oklahoma in town.

For high-end severe weather precaution, The University of Oklahoma main campus in Norman closed that day; so, I was off from work that afternoon. For those of you who do not know me too well, I earned a degree in meteorology (atmospheric sciences) and have experience as a weather forecaster. Additionally, I have also done some meteorological research and try to remain at least somewhat active in the "weather community." The reason why that is important here is that I chose to leave the safety of my home that day in central Oklahoma. I chose to head south and west to where I thought storms would form. Given an equal probability of high-end severe thunderstorm activity, I would much rather be mobile than remain in the same spot. That way I can intentionally avoid being impacted versus having to "ride out" a high-end event, albeit rare even in a High Risk. Moreover, this trip might also give me and the girls an opportunity to do some hiking in the Granite Mountains (yes, Oklahoma has mountains), assuming we left early enough. To my point, though: unless a person has advanced training and/or experience in meteorology (e.g. Advanced Skywarn training, a degree, shift work as a forecaster, etc), I do not recommend storm spotting or "storm chasing". This sort of activity can be dangerous, if not from impacts related to severe weather, from impacts related to driving. Another option might be to tag along with someone who has such training or experience. Either way, be careful!

We left Norman early that afternoon under a layer of smoke. This unusual layer of smoke would become important as we headed south and west as it limited what would have probably otherwise have been good viewing conditions. Besides its reputation for high tornado frequency, most tornado-spawning supercell thunderstorms in Oklahoma are also easy to spot if you know where to look due to the absence of low clouds around such storms. This makes viewing tornadoes and other severe weather features much easier here than other tornado-prone regions like say the Midwest and Southeast. The density and height of tree cover also tend to be less in central and western Oklahoma than many other tornado-prone areas outside the Plains region. And while Oklahoma does tend to be hillier than one might expect; these hills can make for ideal "lookouts" to spot storms. Also, one urban area tends not to run into the next in most sections and tall stalks of corn are rare just about anywhere in Oklahoma. Despite that, the views on this day were restricted by smoke to maybe only 10 miles at best. Whether or not the smoke would have an impact on thunderstorm activity was a matter of debate in my Honda as we neared Carnegie. At Carnegie, we stopped off at a grocery store to buy some fresh food and to take stroll around town after lunch beneath the yellow-orange skies.

After enduring a brief period of blowing dust generated by a pretty random collapsing storm as we departed Carnegie, we left for the Granite Mountains...believing that the most intense thunderstorm activity of the day would probably form in the vicinity of a dryline to our west out in the Texas panhandle. Having looked carefully at model Skew-T data that morning, we estimated that any storm out that way should propagate toward our general vicinity in southwest Oklahoma. Essentially, this would allow us to do some hiking and then follow a storm back towards home. So, basically letting the storm follow us versus us following the storm. Unfortunately, for us though, our cell coverage was quite poor in and around Carnegie. Nevertheless, we continued onward, trusting (even more) morning model output while realizing by now that we probably left too late in the day to do some hiking.

Now on a mission to spot versus hike, by the time we reached the town of Granite, we were lucky to have had at least some cell coverage. This limited coverage allowed us to get a brief glimpse at some radar data. For spotting, we started using RadarScope a few years prior. This software, this app, is practically a must have for storm spotters and its license is fairly cheap to obtain for thrifty-minded people like us. We also tuned into NOAA Weather Radio when we reached Granite and were able to glean some more weather information that way. Still nothing though as far as Google Chrome goes; hence, no analysis charts or satellite imagery. Nevertheless, by then, it was clear that storms had indeed initiated off to our west and were generally tracking towards southwest Oklahoma. Again, we pieced this together by looking at a few radar images coupled with information we heard via NOAA Weather Radio. From what we could tell there were two supercells: 1) one to our northwest which was "dangerously" close to a stationary front; and 2) one to our southwest in what we guessed was probably a much more open warm/moist sector.

Believing that low-level vertical shear was probably strongest near the front, I chose to intercept the "northwest supercell." I did this by heading to the west, and then to the north, of Granite. While this intercept provided evidence of what can happen to air inside a cooled automobile cabin when crossing a front; the supercell in question appeared to propagate over top cold air on the other side of the front. When this happens, storms seldom go on to spawn tornadoes. This is probably because the storm is now in a much less favorable thermodynamic environment on the other side of the front.

Thinking the northwest supercell would become more of a producer of (harder to spot) straight-line wind gusts and heavy rainfall as it "amalgamated" with other probable elevated storms, we traveled back south. We did this in a fashion to move towards the southwest supercell, which we reasoned was probably looming just to the south and west of Mangum by then. As we traveled south at highway speeds towards Granite and Mangum, Bon noted how she could make out some mammatus through the thinning smoke aloft. She also noted how the mammatus was connected to a stout, towering updraft below. Surely, this was the southwest supercell. I was more focused on the road some 100-200 feet in front of me, which was wet from the passing convective showers, but took her word for it.

As we approached the intersection of Highway 9 on Highway 283, just west of Granite (and to the north of Mangum), light to moderate rain began pelting my Honda. This was rainfall in the northeast portion of the southwest supercell's precipitation cascade. Reasoning that the precipitation intensity was likely to increase if we traveled south any farther, we decided to make a left turn onto Highway 9 just west of Granite; basically, backtracking from where we were earlier. After driving about two miles to the east on Highway 9 toward Granite, we were out of the supercell's precipitation cascade to the west. Wanting to take a closer look at the situation in rain-free air and stretch a bit, I pulled off onto a north-south, dirt-stone, farm-ranch road. Now out of my vehicle, I paced along the dirt-stone road while noting how murky the sky looked. This was hardly a very photogenic supercell, I thought, as cool northeast winds hummed through the power lines above. At that time, I could also hear what sounded like nearly continuous rumbles of thunder from high aloft. I reasoned this was probably the sound of both actual thunder and of hailstones being smashed into one another high aloft. I have only observed this rumbly audio signal of sorts with thunderstorms that produce large hail; hence, it seems reasonable to conclude the sound is indeed related to large hail.

After about 10-15 minutes of pacing around, occasional "spits" of drizzle and light rain drops began falling as cool northeast winds strengthened and became gustier. However, the heavier precipitation remained off to the west. I knew as much because of how dark the sky was to the west. At around this time, I could also begin to make out a wide precipitation shaft off to the west through the murky air. Within a minute or two of noting the large precipitation shaft, Bon altered me of a tornado warning in our area. This warning was broadcast via the emergency alert system radioed to our phones. As I paced back toward my vehicle, I noted what looked like a second precipitation shaft to the south of the large one to the west. This "shaft" of sorts was much narrower and moved at a wide angle to the precipitation shaft to the west, which appeared to be progressing more north than east. By the time I got in my vehicle with Bon, some hail had begun to fall. These stones measured up to around the size of ping pong balls and fell intermittently with the drizzle and light rain. Interestingly, although winds were blowing from the northeast, the trajectories of the hailstones were towards the northeast at about a 30-degree (zenith) angle. Maybe this was evidence of the shallowness of the northeast flow blowing toward where a tornado was in all likelihood in progress, I thought.

While getting seated in my vehicle with the girls, I remained focused on the shaft to the south. In a span of only about 10 or 15 seconds, it became quite clear that the shaft was actually a large tornado. A large tornado in progress some 5-10 miles to our southwest. The erratic motion of the shaft relative to the more steady-state propagation of the precipitation shaft to the west was a good indicator that this was indeed a tornado. We could also make out what appeared to be balls of debris near the surface being lifted up and whirled around the shaft. No sooner did I get buckled in did I decide to venture out, while cautiously, for a few moments to capture the spectacle to the southwest. I also used the short trek away from my vehicle to collect a few hailstones that laid on the ground nearby. Not wanting to be buried in a barrage of precipitation, I headed east into Granite towards precipitation-free air along Highway 9. Meanwhile, Bon called 9-1-1 to report a tornado as well as the occurrence of a few chunks of larger hail that began to fall.

As we passed through Granite, we passed by several chasers and spotters who seemed well aware of the situation. And by the time we got through Granite with its tornado sirens blaring, we noted a string of vehicles amassing behind us. These were most likely other chasers and spotters who realized that it probably wasn't worth it to stick around Granite given the tornado's trajectory towards town. After driving east along Highway 9 to the north and east of Granite for a few miles, we pulled off the highway along another dirt-stone road to "recalibrate." At that point we could clearly see a funnel about a mile or two southwest of Granite. However, we weren't sure whether it was the same tornado as we had seen earlier over Mangum. Either way, we felt that were a safe enough distance away from the storm's mesocyclone(s) to avoid being impacted by a tornado and its (probable, strong) rear flank downdraft. Nevertheless, storms can behave rather unpredictably at times. Hence, while we felt safe to monitor the storm's finer-scale morphology, we wanted to steer clear of the thick of things. Afterall, what if the storm and/or its finer-scale, high-end severity features developed father south and east? Like a new mesocyclone and tornado. or redevelopment of the existing one, for example.

While turning onto the second dirt-stone road we pulled off along was easy, getting back on was another story. Basically, there were hundreds of vehicles headed east toward the precipitation-free air along Highway 9. This nearly continuous string of vehicles hampered my ability to rejoin Highway 9 for at least 10 minutes. Ordinarily, Highway 9 in the Granite area is hardly a heavily traveled section of road. However, on a High Risk day with a tornadic supercell nearby in 2019, Highway 9 became a long train of vehicles of people with widely varying attention to driving. Nevertheless, eventually, I joined Highway 9 and headed slightly north of east on Highway 9 towards Lone Wolf. This move was in an attempt to stay ahead of the storm, just to its south and east.

On our way to Lone Wolf, it became clear that the supercell was probably no longer tornadic, however. And if it was tornadic, surely there wasn't much of an opportunity to view it through the mass of precipitation that developed along the storm's flanks. I reasoned this storm was probably on track to becoming similar to the northwest supercell we had spotted earlier. Still, the storm continued to impress us with its very frequent lightning and now well-sculpted gust front. We followed that storm, its iterations and other newer storms the whole way back to Norman.

Plate 1. Mangum Tornado. Captured on May 20, 2019 at 5:26pm CDT. Looking southwest from 34.96°, -99.47°.