I was chasing with Shawn Hewitt, Rory Groves and Rob Koch. A supercell developed just to the northwest of Manhattan, KS. Shawn, Rob, Rory and I were on this cell watching it for about 45 minutes. It was so much fun just watching it get its act together. It looked like it could have tornadoed for a while there, some other chasers rolled up and met them as well.
We repositioned farther east and stopped ahead of the cell as it was going through an outflow dominant stage. While standing in some high grass appreciating the beauty of the shelf cloud about to pass over us, I could tell that there was a vibration at my feet. The vibration wasn't a big concern as I was paying attention to the storm, but my sub concious knew about it. I paid more attention to it when it got more pronounced and I realized the vibration was the movement of long grass blades being pulled out from under my shoes. Just then whatever was moving around in the grass causing the grass blades to move scampered up my leg and I freaked out and ran. Out of the corner of my eye I could see something, either a mouse or a snake fling out of my pant leg into the grass. I had the heebie-jeebies for about 20 miles.
When we followed the cell east is when it really did it's business, and there was a rain-wrapped tornado in there as other chasers were able to sneak a peak. We played this thing like a fiddle and were ahead of the hook the whole time. Unfortunately with the huge rain core the most we saw was a power flash.... but looking at the storm reports, it seems there was a tornado in there, as we kind of expected.
Damn that lack of shear aloft to tilt the updraft so the rain was out of the updraft base!
A pilot reported a tornado was on the ground north of Kansas City International Airport, north of Kansas City, Mo. The KCI tower was shut down and evacuated.
Notes on this system from Mike Peregrine:
"Our video camera grabbed the shot of the weak condensation funnel at approx. 4:50 p.m., if that helps. At 5:00 p.m. we were overtaken by the hail core - because of the nature of the event, I believe we took a direct hit from the center of the core. The rotation was directly to our south at this point, no more than 2-3 miles, near the town of Potter, KS - just minutes before the circulation passed over the Missouri River. We were tired of getting beat up by this storm so instead of going south to Leavenworth, we opted to go north and cross the river at Atchison to come home. Normally on storms I am able to stay under inflow fairly easily, but once we were caught up by the downdraft it seemed like it was just IMPOSSIBLE for us to stay away from it this time, no matter how hard I struggled to do it ... the storm just kept overtaking us - - - which was scary to me at the time, but in the end it was the only way for us to see what we did. I would love for a shot or two at a classic supercell around here, but it seems that NE KS/NW MO is destined to remain in HP hell forever."
An email from Mike Hudson, the WCM of the NWS in Kansas City:
Thanks for the report and follow-up on e-spotter. I believe we did have a tornado touchdown south of Atchison on 4/21. Mike Peregrine shot some stills of what appears to be a rain-wrapped tornado in that location (pix are posted at http://www.stormtrack.org/forum/viewtopic.php?t=6070).
From his pictures and other eyewitness accounts in that area, I have rated an F0 tornado touchdown at that location."