Green Sky Chaser

9 June 2009 Chase Log

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Target Area: Wellington/Arkansas City, Kansas (Click on city names for Yahoo! maps links)

Chase Area: Wellington/Arkansas City, Kansas

Observations: three or so supercells (hard to tell when you're surrounded), one wall cloud, and a rainbow

Distance: 450 miles

Time: 9 hours

Chase Team: Rob Warren and myself

SPC Convective Outlook: Moderate Risk (downgraded to Slight by 0100UTC) (Click to see SPC products, data, and storm reports)

Chase Setup: Similar to the previous week's setup, zonal flow was in place across much of the U.S., but this time upper-level support was better with stronger winds. A surface low set up around the northwest Oklahoma/Kansas border, with a dryline extending southward through west Oklahoma and a cold front extending eastward through southern Kansas. With dewpoints in the mid- to upper 60s and CAPE of over 3000 J kg-1 from Wichita Falls, Texas through much of Oklahoma up to the Kansas border, there was a good chance of some strong thunderstorms. Moderate to strong helicity values of 300 to 400 m2 s-2 found in north central Oklahoma/south central Kansas to southeast Kansas.


Chase Log: This was the last chase I went on with Rob, before he headed back to England. I had to work again until early afternoon, so we got a bit of a late start as we drove up to Wellington. I wasn't terribly optimistic about our chances of seeing a tornado this day, but I was fairly confident that it was a pretty good June setup and we at least had a good shot at seeing a supercell and some nice storm structure.

Although we had a late start, we wound up sitting at Wellington for a while, waiting for storms to form in the clear sky. Eventually I saw a weak radar echo on my laptop, from a skinny-looking, small cell near Dodge City. I joked with Rob that that would be the storm of the day, and I made my prediction (not a serious one) that the skinny radar echo would become a beast and produce the tornado that we wouldn't see. I even named it Rebekah's cell. We were bored.

Finally we got a storm to fire just east of our location, so we drove off in that direction (it was in a more favorable environment than the storm to our west. Before we knew it, we were surrounded by three supercells in low-visibility conditions. Despite a broad area of rotation around a ragged wall cloud, conditions did not look promising. Forced to core punch, in the unlikely but possible event that a tornado could form near us and we wouldn't even see it, I drove through the weakest-looking storm. By the time we got out of the mess, the supercells had unfortunately merged into a bow echo. We did wind up at the north bookend vortex, though, near the most likely location for a tornado to form.

In the end we did see some nice storm structure and a double rainbow, and we did have a pleasant storm chase.

Need I say that Rebekah's cell grew and went on to produce a brief tornado near Greensburg?


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