Wednesday, April 7, 2010
Dick McGowan's photos of 4/6/10 Wakeeney KS tornadoes
Dick McGowan (www.tornadolive.com) was kind enough to send me a few images from his Wakeeney KS chase yesterday, to compliment my earlier post about the meteorological setting for these unusual tornadoes (surface temperature mid 60s F, dew points mid-upper 40s F).
The first image shows the first tornado north of the interstate, with a condensation funnel well aloft and dust circulation at the ground. Dick says this tornado formed rapidly from a bowl-like high-based mesocyclone circulation and lasted maybe 2-3 minutes. The last image shows this tornado dissipating (right) with a 2nd tornado at left in what appears to be an occluded area. Dick says this 2nd tornado lasted about 3 minutes, and even hit a small farm structure, lifting pieces of debris into the air.
Looking back at the Hays RUC profile in my previous post, the high cloud bases and steep low-level lapse rate suggest to me that these tornadoes may have been a "hybrid" type of event, combining supercell and non-supercell processes, with significant heating at the surface (possibly upper 60s F) and very cold temperatures not far aloft (0 deg C around 700 mb). Dick says that he had the visual impression of updrafts that were shrinking horizontally and stretching very rapidly in the vertical as the tornadoes occurred. At any rate, these weak tornadoes occurred in an odd location relative to the surface pattern, away from the deeper moisture, and were the only ones I know of that were photographed over the past 4 days of severe weather in the Plains.
Dick, thanks for sharing these images.
- Jon Davies 4/7/10
Update 4/8/10 AM - I looked back at the surface analysis I did in the previous post, comparing it to Dodge City radar base reflectivity just before 2100 UTC on 4/6/10, and found I missed a boundary (Dick McGowan also mentioned this). I've drawn this in on the updated surface map (with radar) above, suggesting that the Wakeeney tornadoes occurred at or near a pretty decent boundary intersection, which may have added some nice vorticity ("spin").