2005: APRIL 11: NORTH KANSAS SUPERCELLS

    I was minding my own business on the way home to Indiana when all of a sudden.... No, not really. I had all the gear running and ready and was happy to see a field of vertical three o’clock cu in east central Kansas along Interstate 70 by 17z. Today’s setup looked like a slimmed-down and trimmed-back version of yesterday, a little less instability, a little less shear, weaker and backed midlevel flow, but with the same steep lapse rates and enough low-level shear and sufficient LCLs to make it another interesting day. I found a great long-lived storm, the Washington County supercell, which produced an ominous, vacuum-cleaner style rotating updraft base and later unleashed the single most bizarre and unexpected thing that has ever happened to me while chasing.

Early in the day, I spotted an area of persistent towers northwest of Manhattan, and this became the Washington County storm. It produced several sustained wall clouds with varying degrees of rotation and finally organized itself dramatically between Greenleaf and Washington, Kansas, just south of state highway 36. Mike Hollingshead and I observed this storm as it snagged a boundary—either outflow or what I analyzed as a pseudo warm front in this approximate area—and anchored itself stubbornly, with an aborted split (with precip blowing northwest onto the newborn updraft, it didn’t have much of a chance), and propagation both to the south and the southeast. The southeast updraft grew dominant and Mike and I flanked it east, and observed the very low, carousel style updraft. The feature was composed of white condensation with tendrils that articulated the circulation. We were convinced it would tornado immediately. We perched on a hill and watched the storm wrap up again—the circulation tightened to an extremely rapid motion. I was stunned that there was nothing beneath. I haven’t seen that kind of rotation from such a low feature without a tornado beneath it. This was around 21z.

We chased this storm and its various moving parts across the Nebraska border toward Odell, where we met up with Jonathan Garner and his chase partner. For some time, our storm had served as the intersection for a line of convection stretching to the northeast along the cold front, and to the southeast along the not-so-dryline advancing from the southwest. As this angle closed, convection approached from all sides. Our storm had no hope of uncontaminated inflow and we determined as well that we were nearly in the center of the surface low. XM streamlines confirmed this.

We stood outside our vehicles on a muddy dirt road, heads moving in all directions as the cloud motions were turbulent and quick areas of rotation appeared and disappeared. Our winds were light and northerly, then they calmed. Then they swung around out of the east, and then from the south, a little warmer than before. The next moment, in field of tall and bright green vegetation about thirty yards away, a flattened circle appeared that reminded me instantly of the crop circle hoax in the UK. The only difference was that this circle was rotating vigorously and racing toward us. I pointed and yelled “What the hell is that?” But it was on us before anybody could take a guess.

Mike turned and held his open car door, both to keep it from ripping off and to keep his feet on the ground. I crouched and turned away, gripping the side of my 4Runner with one hand and shielding my face with the other, as the winds blasted us with gravel and sand and tried to take us off our feet. It was amazing! When the circulation passed, a hard driving burst of precipitation came straight down on us for about fifteen seconds. We estimated the wind speeds in the circulation at between seventy and eighty knots. Mike reported a sense of weightlessness during the event. I’m convinced that if the vegetation in the field had been dead, it would have remained flattened.

Nobody mentioned having seen circulation in the cloud base overhead preceding the event. However, I don’t know that I was looking up there anymore than I was looking elsewhere—it was a ragged, cold air storm base the likes of which we’ve all seen. It was so benign in appearance that none of us even had our cameras out, let alone recording at the time. However, the sequence of the wind shift and the immediate precip is fascinating to consider. Was this a very weak tornado? I don’t know; I’m not trying to begin a debate. It was a vigorous circulation on the ground, that much I can say with confidence.

Soon the storms congealed into a large mess and we broke off the chase. It was great to see Mike again and I was glad to meet Jon and his chase partner. I thought I was in Nebraska too early last year—wow. It’s April and there I was again. A fun and unusual chase to cap off a happy three-day plains trip, starting with the cool get-together at the Vista in Norman, followed by one of the best chases of my life in Kansas on Sunday, and ending with a close encounter of the rotational kind in a south Nebraska field. 2005 is off to a great start.

 


 

Video grabs below



Images above from ~2030UTC eastern Washington County, KS, April 11, 2005

 

Cyclone Road