Chase Log: August 26th, 2016 Perry Lake, KS Supercell

A local chase day only three days after my first tornado resulted in some good HP supercell structure and some nice rainbows on the way home. A line of storms with embedded supercells developed in Northeast Kansas and moved northeastward, and I chased one embedded supercell from just north of Topeka, Kansas to north of Oskaloosa, Kansas. While the storm was never severe or tornado warned, it had some textbook HP supercell structure, and I was quite satisfied with my chase.

During the morning of the 26th, I was keeping a close eye on things, as the SPC had a Slight Risk of severe weather with a 2% tornado risk for Northeast Kansas. They had mentioned it may need to be upgraded to a 5%, and in the early afternoon, a Tornado Watch was being considered for the area. After 3 pm, storms were firing north and west of Topeka. However, none looked very promising, and I waited until a good storm developed. Around 3:30, a supercell formed from a complex of cells just northwest of Topeka and had reports of a wall cloud. I took off northward, intending to intercept the storm northeast of Topeka near Meriden, Kansas.

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~3:45 pm, just north of Topeka, Kansas. A shelf cloud signifies the rear-flank downdraft of the storm. Behind this shelf is some very heavy rain.

I drove northeast towards Meriden and positioned myself in front of the mesocyclone. The supercell had started to become embedded within a larger line of storms, so it took on HP characteristics and the rear-flank downdraft became clouded with rain. However, the wall cloud was still visible.

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4:05 pm, south of Meriden, Kansas. The wall cloud is in the center of the picture, with the rain-filled rear-flank downdraft to its left. While present, the wall cloud was not particularly impressive, and only had mild rotation at this point.

As I entered Meriden, I parked in a parking lot and waited for the storm to come to me. The wall cloud passed less than a quarter mile to my northwest, and had moderate rotation visible. If a tornado had touched down, it would have been very close to my location. The rotation passed to my north and the rain of the rear-flank downdraft swept through Meriden. The rain made it quite difficult to drive, and often I had to slow down to less than 50 mph on the highway. I decided to head north and east more, to get ahead of the storm once again. I escaped the rear-flank downdraft as I crossed Perry Lake, and headed towards Oskaloosa, Kansas.

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4:38 pm, west of Oskaloosa, Kansas. The wall cloud is again in the middle, with the rear-flank downdraft behind it and to its left. The wall cloud is not particularly impressive here either.

Interestingly, not long after this picture was taken, the wall cloud became larger, and a well-defined tail cloud developed. I thought things might get interesting here, but after about 8 minutes, it fell apart as I entered Oskaloosa. I continued a little north of Oskaloosa, but as the storm caught me, I decided to call the chase and headed back to Topeka.

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~5:15 pm, Topeka, Kansas. As I came home, I spotted several impressive rainbows, with this one east of home the best. A double rainbow is occurring here, with the bottom one very easy to see, and the top one barely visible.

I had some higher expectations for this day, but even though there was no tornado, some good HP structure and a display of rainbows more than made up for it.

Some Meteorological Analysis

The tornado threat seemed pretty good to me in the early afternoon. While storms were expected to eventually form into a line, early in storm evolution the tornado potential seemed fairly decent. There was 40 kts+ of 500 mb flow, with a surface low near Manhattan, Kansas and a warm front extending from the low southeast towards Kansas City. The supercell was in an environment of ~2000 SBCAPE, 40-45 kts bulk shear, but only ~150 SRH. The lack of low-level shear may have stopped the tornado threat. It seemed to me that storms may have initiated too early, thus going linear too quickly. Had the storms initiated later, and remained discrete later when low-level shear increased, there may have been tornadoes. To this point, as the line of storms moved into Missouri, the supercell I was chasing remained embedded in the line and produced a couple tornadoes south of Cameron, Missouri. An interesting case.

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Chase Log: August 23rd, 2016 Clay Center, KS Tornado/Supercell

My first tornado on a chase and second overall came on a 2% tornado risk day in August 2016 in North-Central Kansas. A brief tornado occurred near Miltonvale, Kansas around 7:15 pm, and I observed it from over 25 miles away. Because I was so far from it, and I was driving at the time, I didn’t get any pictures of it, but it is a memory I will hold forever.

I payed attention to the SPC forecast for August 23rd, as they had mentioned some tornado potential in Nebraska the day before. The day of the event, however, the morning discussions only had a 2% tornado risk in Nebraska and Iowa, so I didn’t think much about it. In the 3 pm update, a 5% tornado risk area had been added to Southern Kansas and Northern Oklahoma, where a couple tornadoes were possible. Many chasers went to that area. There was also a 2% risk that extended across Central and North-Central Kansas. Around this time, I noticed some echoes on the radar near Salina, Kansas. I set off for Manhattan, Kansas, where I planned to go fishing, and if the storms looked good, I could go west and chase. I fished until about 6 pm, when I noticed on radar that a single, isolated supercell had developed in Cloud County, Kansas, about 60 miles from where I was fishing. I decided to head towards Clay Center, Kansas and try to intercept the storm.

As I approached Clay Center from the west, the storm was due west of me by over 25 miles. However, I could clearly see the updraft base, and as I continued westward, a small lowering. I kept an eye on this lowering, and within a few minutes it turned into a full-fledged funnel. It appeared to me to be about a quarter ways from the cloud base to the ground. As I was driving, I was unable to get a picture of it. It wasn’t until hours later that I knew that it had actually briefly touched the ground, and thus was a tornado. A storm chaser who was less than a mile from the tornado recorded it and posted it on YouTube: https://www.youtube.com/watch?v=YPpKrirWxmc&feature=youtu.be&a

Around the 1-minute mark, the funnel can be seen in its developmental stage. Further along the video, it becomes a full-fledged funnel cloud, and the video then shows the debris cloud where the funnel cloud touches down and becomes a tornado. I was unable to see the touchdown, but I am certain I saw the funnel. As I went into Clay Center, the tornado/funnel dissipated. I decided to head south from Clay Center, as the storm was slowly moving southeastward, and heading south and then west would be my best option.

Heading south of Clay Center, I drove through a network of gravel and dirt roads. I figured it would be best to stay well away from the precipitation of the storm, but close enough to see the mesocyclone. I never got too close to the storm, and stayed out of the rain and hail the entire chase. The following photos are in chronological order.

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7:32 pm, looking west. The updraft base is visible in the middle, where there is little precipitation falling. I had bad data coverage at this juncture, but a Tornado Warning was issued a few minutes before this.

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7:44 pm. I repositioned south and west to get further away from the precipitation and wind of the storm. the rotation in the storm is evident in this image, as the mesocyclone is visible in the center-left. A new mesocyclone is forming to the right. Not long after this picture was taken, a bolt of lightning flashed overhead, and the thunder was deafening. I wouldn’t be surprised i

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8:00 pm. Heading further south, a new updraft formed to the east of the first one. They competed for control of inflow, and neither produced a tornado after this point.

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Both updrafts are visible in this picture, with the old one that produced the tornado to the left (west), and the new one to the right (east). Some sort of gust front started to move towards me at this time, so I repositioned southward.

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8:16 pm. Although the new updraft to the east had taken some of the old one’s inflow, it appeared that the old updraft was trying to produce a wall cloud. More upward motion was occurring at the base, and the cloud base was lowering.

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8:20 pm. The attempt at a wall cloud didn’t last long, however, and soon returned to an updraft base that has some rain falling in it.

After this picture was taken, sunlight began to fade, making it difficult to see features in the storm. It also appeared that the storm began to weaken in terms of rotation, so I decided to head home. I was treated to a spectacular lightning show on my way home.

As I came home, I checked the SPC page. To my surprise, the page listed that a brief touchdown occurred around 7:15 pm west of Miltonvale, Kansas. I checked some things and I discovered that the report and the funnel I saw were at the same time. I didn’t realize I saw my first tornado until 3 hours later!

Brief Meteorological Analysis

The tornadic storm was not forecasted very well, but the NWS did well as it occurred. Looking at a sounding from Topeka, Kansas (the closest site), we can make some guesses to the storm’s environment.

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The picture is hard to make out, but at 7 pm at Topeka, there was ~2200 MLCAPE, 31 kts of bulk shear, and 272 SRH. I would be willing to bet that both bulk shear and SRH were higher in the storm’s inflow environment, with something like ~40 kts of shear and 300 SRH probably a good estimate. While this is not an outbreak setup, it is definitely conducive for tornadoes. A look at the hodograph shows that slow, southeastward-moving supercells have potential for tornadoes. Generally speaking, between 30-35 kts of flow at 500mb won’t get you much, but as there was a strong low-level jet, and slightly backed winds at the surface coming from the south-southeast, it was enough to produce a brief tornado.

My fourth chase of the year was my best so far, before I knew about the tornado. Great structure, beautiful landscapes and nice images produced my best day chasing. The tornado was just icing on the cake.

Topeka, KS MCS August 19th, 2016

On August 19th, 2016 a typical late-summer severe weather setup took shape across the Central Plains. A subtle shortwave brought westerly flow across Kansas and Nebraska, while a cold front swept across the region. Some mesoscale features also helped with thunderstorm activity, and a Slight Risk of severe weather, mainly for the threat of damaging winds, was placed from Western Iowa southwest-ward into Northwest Oklahoma. I had kept my eye on the weather for the day, and considered chasing if the opportunity arose. Late in the afternoon, an MCS, or mesoscale convective system, formed over North Central Kansas and moved southeastward. I saw this taking shape on radar, and I set off to chase it. As I looked at radar and at the sky, the storms didn’t look very impressive to me. I decided that it wasn’t worth chasing, and went to Walmart instead. This decision may have been a blessing.

After I bought a few things, I exited Walmart to a breathtaking sight. In the sky to the west was a pretty nice shelf cloud.20160819_184015

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I ran to my car as it had started to rain, and as I drove out of the Walmart parking lot, it started to pour. 45 mph wind gusts brought leaves and other small debris across the road as I headed home. As I got home, I thought the worst was over.

Right as I pulled into my driveway, the storm turned into a hurricane. Very heavy rain along with high winds made it difficult to see out my window. I dashed to the garage and opened the door. The rain kept coming, and the winds only got stronger. As I watched from my garage, a gust of at least 55 mph came over the house and smashed into the trees in my front lawn. A medium-sized branch was snapped off a mimosa tree.

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Eventually, the storm let up, but strong winds and heavy rain continued for another 30 minutes. All in all, for a late summer storm, August 19th exceeded my expectations.