Chase Log: April 23rd, 2007

Click on any of the SPC products below (Convective Outlooks, Watches, or MCDs) to see the SPC's "Severe Thunderstorm Events" page pertaining to this event.

NO CHASE MAP EXISTS

Total Distance: 620 miles
Target Area: Pampa, TX, to Memphis, TX
Chase Area: Buffalo, OK, to Protection, KS
Maximum SPC Risk category: Moderate
Watches:
Mesoscale Discussions (MCDs):

A potential "day before the day" event, as southwest flow aloft led to lee troughing. With moderate moisture in place, moderate instability was forecast to develop across the Texas panhandle, Oklahoma panhandle, western Kansas, and eastern Colorado by afternoon. With the upper-level trough still well to the west of the threat area, the flow aloft was forecast to be relatively weak. Given this, the dryline was not going to be particularly strong, and there were major concerns over convective initiation owing to weak low-level convergence. Regardless of what was going to play out, we liked the relatively slow storm motions, strong low-level shear, and nice terrain.

Wow. I, Dan Dawson, Robin Tanamachi, Gabe Garfield, Jana Houser, Chris Emersick (sp?) barely recovered from what we thought was an imminent bust. We waited an hour or so in Shamrock, hoping for convection near Clarendon or Silverton to develop and sustain. Seeing that this may not happen, we jetted northward towards the convection in the extreme TX panhandle and extreme nw OK. We finally caught up to it north of Buffalo. We saw our first tornado ESE of Sitka. Punching through the light wrap-around precip, we then spotted a small tornado to our southeast (which would put it just SW of Protection). Then, a slightly larger tornado to our immediate south. Then yet another tornado to our west. Yup, I think there were three tornadoes on the ground at the same time between Protection and Sitka. The westernmost tornado was largely an elephant trunk in shape, and it even went through a drill-press-like state. I've never seen three tornadoes lined up like that... All of them were associated with organized cloud-base rotation, so it almost appeared like a multi-vortex mesocyclone, with three embedded tornado cyclones.

We followed this storm north of Protection before watching it weaken (though we got some good lightning pics). It appears as though we got to the storm just in the nic of time, though. As we drove through Canadian, the updrafts looked quite impressive, with rock-hard towers and tops. By the time we entered into OK and drove through Arnett, however, they looked quite leaned-over. We almost, almost gave up, but decided that we just wanted a view of the base. When the base finally came into view, we were extremely surprised to see a large, low wall-cloud west of Buffalo (DZ wasn't impressivel). A bad road option almost cost us, but all is well.

While between the precip core and the mesocyclone on Hwy 160, we advanced through the light-moderate wrap-around precip to witness a fantastic, tiered updraft. It looked a lot like the Attica updraft of 5-12-04 fame... Incredible structure from that vantage point, and surprising considering that it looked like the tower was leaning more than 45 degrees earlier. Total tornado count: ~7 in Clark and Comanche counties, KS. I have 5 on video, and the passengers in my car (Gabe and Jana) were seated in much better position to view two more.

04-23-2007 Chase Pictures

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