The fact today would be my first chase this month was a sign what kind of month this had been for the southern Plains and for me. A strong ridge of high pressure on the west coast helped keep severe weather to a minimum during the first week of the month. This pattern reversed itself during the second week of the month, as a persistent trough set up on the west coast. Strong southwest flow aloft over the northern Plains brought many episodes of severe weather to Colorado, Nebraska, and Iowa during the second and third weeks of the month - while most places south of I-70 baked under an unseasonably strong subtropical ridge. Due to a limited budget I chose not to do a multiday excursion this year, so I missed all the activity up north during the third week of the month. And on the one day this month there was actually chaseable weather within 300 miles of Norman (May 12), my car's alternator went out. Needless to say I was excited when medium range forecast models were indicating the stronger southwest flow aloft dipping south into the southern Plains during the last full week of the month.
Today the SPC had issued a high risk for areas along the warm front in southeast Nebraska, northwest Missouri, and southern Iowa. Although this area would be a bit out of reach for me, it looked like areas further south would be in play as well. Eastern Kansas looked interesting as a deep surge of moist, unstable air was moving north into the area and the dryline was bulging northeast into the area by early afternoon. The cap would not be much of a problem here either as Topeka reported a 700mb temp of 7 degrees Celsius at 12z. Storms were even possible in Oklahoma today - even with 700mb temps of 10-12 degrees Celsius a core of 60+ knot winds at the 500mb level were taking dead aim on the state. The only drawback would be temp/dewpoint spreads of 20-25 degrees or greater, which would mean storms in Oklahoma would probably be high based. So with prospects of a weaker capping inversion and lower temp/dewpoint spreads in Kansas I decided to head north today. So just before 3pm I left Norman and headed north on I-35.
Around 4pm I began seeing turkey towers trying to break the cap off to my north and northwest. I kept an eye on these as I continued north to Braman, where I stopped to top off my tank. By this time the towers were just to my north and northeast, and shortly after I got back on the road and crossed the border into Kansas the towers began to go nuclear. I briefly entertained thoughts about going after them, but since they were extremely high based and racing eastward into a terrible road network at about 50 mph I let these go. By the time I got to Wichita, I began noticing towers trying to go up well off to the north, so I continued heading up to Kansas Turnpike. These towers disappered after about 15 or 20 minutes, but as I was approaching Emporia I began to notice the sky was filled with low stratocumulus - whose bases were much lower than the stratocumulus and cumulus I had seen in Oklahoma and southern Kansas. This signalled to me that I was in the lower temp/dewpoint spreads - which the obs I was hearing over the NOAA Wx Radio was verifying. Wichita was reporting temps in the mid 90s and dewpoints in the upper 60s while Emporia was reporting temps in the mid 80s and dewpoints in the low 70s. There were no signs of cumulus development however until I was just southwest of Emporia. By this time I began to make out the outline of towers going up to my northwest and north. I began to get a little disappointed when I got to Emporia to see there were five mushy looking towers developing in a line, which reminded me of what happened north of Tulsa on April 20. But as I headed northeast out of Emporia, I began to notice the second tower begin to boil skyward like a mushroom cloud and even show signs of rotation. I exited off I-35 and headed north up Hwy 99, continuing to watch the storm as it absorbed a mushy cell to its southwest and develop a large rain free base. Scud began rising into the base (which was now about 10 miles to my north) around the time I got to Admire and started heading east on US 56. I was just north of Miller when I noticed rain curtains begin to wrap around about 8-10 miles north-northwest of my location, and was excited that my long tornado drought might soon be over. The rain curtains were not so dense that I wouldn't be able to see anything, so I kept a close eye on this area as I headed east through the rolling terrain. After about 5 minutes, the rain curtains thinned and a lot of scud began condensing low to the ground. Rising motion and rotation was fairly weak, and it no longer looked as if a tornado was imminent. Still the supercell had some impressive structure and was featuring a fragmented inflow band extending to its east. I was unable to find a good place to get a picture from US 56, so I headed up some back roads trying to find a better vantagepoint. But I was unsuccessful here as well, so I continued on my way back on US 56.
On my way back to US 56 at 7:42pm, I heard a statement over NOAA Wx Radio that law enforcement had seen a tornado west of Harveyville at 7:38pm, and that the storm had a history of producing tornadoes. Immediately I began to wonder if I had finally witnessed the sheriffnado phenomenon, as all I had seen in that direction at that time was the low hanging scud and weak rising motion and broad rotation. In the meantime I got back to US 56 and started heading north, watching the RFD evaporate cloud material off to my northwest. I also noticed a new cell forming off to my west, and seeing that if I kept going north I would soon be under the vault region of the old cell, I decided to turn around and head south to avoid being boxed in by the new cell. I picked up Hwy 31 in Osage City and went east to stay ahead of this new cell. Once east of Osage City, I got a call from my chase partner Jay Barnes who was at home in Texas. So I pulled over and asked him what kind of reports he was seeing on the computer. As we were talking, the core of the cell to my west was coming up on me fast, so we ended the call and I began heading south on US 75. An intense barrage of quick CG's from the anvil was striking all around me as I went south from Lyndon, and continued to do so as I got to the intersection of US 75 and I-35 at 8:30pm. By this time darkness was beginning to set in and new storms were continuing to develop to my southwest, so I decided to break off the chase here. I went south on US 75 to avoid getting slammed by the new development, and as a result didn't see any rain until I got back into Oklahoma. I actually got into a severe warned cell just northeast of Oklahoma City on the way back, but didn't see any hail or wind. I did see one brilliant CG that overwhelmed my retina so much I could still see the afterimage a full minute later!
The cells I chased in the Topeka area reminded me a lot of the cells that formed in Oklahoma between April 20-23. One is that a lot of cells went up at once and ended up seeding each other. Another is that there may have been a few bogus tornado reports. There were two reports of tornadoes near Harveyville and a report of a tornado south of Auburn from the intial cell I chased. If the times on these reports were correct then I believe all of them are in error - all I saw at the times of these reports was a lot of low hanging scud. I didn't see any areas of tight, rapid rotation at the times of the reports - if the Harveyville cell was tornadic, it probably would have been around the time of the wrapping rain curtains, which occurred 10-20 minutes before the reports. Some credible chasers believe they may have seen a tornado near Lyndon near dark, although it was difficult to tell due to the terrain and the low light. I myself was too far away to see this feature as I was in the process of breaking off the chase and heading south. The surprise of the day however were the storms in Oklahoma - at least one of them was actually tornadic and appeared to do F1 damage in the Alfalfa area. TV stations showed some good video of a needle tornado in that area. Wouldn't you know it - the day I finally take a gamble up north, a tornado happens about 60 miles away from my apartment! That's chasing for you.
Total Mileage: 655 miles
Total Driving Time: 11 hours, 0 minutes
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