Mission Summary 6/08


The first storm targeted by VORTEX occurred in the Oklahoma Panhandle in the middle of the afternoon. The storm was on a surface front. AN elongated mesocyclone formed near Elmwood in Beaver County, and moved toward Laverne and Rosston. This storm produced softball-size hail, severe surface winds, and a brief funnel cloud, but no tornadoes. It was well-sampled by VORTEX.
After the Elmwood storm transitioned into a weaker HP supercell, the VORTEX armada moved south toward the eastern Texas Panhandle. We bypassed a storm near Spearman because we felt it would also be an HP storm. A tornadic storm had developed near Pampa and was moving NNE, but we realized it was over open country in the Canadian River bottomland west of Canadian, TX, and would not approach any major roads for at least one hour. Therefore, we targeted a new tornadic storm near McLean TX (on I-40 in the eastern TX Panhandle).
Unfortunately, the Pampa tornado had sufficiently destroyed the power distribution network that no electricity was on in any of the communities that we traveled through in the TX Panhandle. We were told that power would be out for at least 24 hours. This means no gasoline pumps! Three of our teams ran out of gas while looking for electricity around Shamrock. Three others ran out of gas near sunset.
However, most of the armada intercepted the McLean storm near McLean. The NOAA P-3 and the NCAR Electra had already been gathering data on this storm for over an hour, including the spinup of a brief tornado just north of McLean (and perhaps others between McLean and Clarendon).
A large, violent tornado formed just south of Kellerville and moved to a point NW of Wheeler, TX. Surface teams were on several sides of this tornado. South of Kellerville, the pavement was completely removed from highway 1443. The mobile scanning Doppler obtained data on this tornado scanning toward the southwest.
Meanwhile, a twin supercell was also moving NNE just west of the target storm. This storm also produced (perhaps several) tornadoes between Alanreed and Mobeetie.
The target storm underwent another phase of cyclic tornadogenesis just southeast of the demise of the Kellerville tornado. This occurred between Wheeler and Briscoe. The second large, violent tornado that we observed developed about 6 miles southwest of Allison, TX. It moved directly toward Allison, but veered to the left just prior to striking the community, and passed 1.5 miles west of town. It then meandered to a position about 3 miles northwest of Allison and remained nearly stationary for a period of about 20 minutes.
This tornado was well-sampled with the mobile mesonet, and perhaps with the mobile scanning Doppler, as well as with the NOAA P-3. Teams were positioned SE-NE of the tornado, as well as west of the tornado as it crossed the highway west of Allison. The mobile scanning Doppler as well as WSR-88D depicted as many as four tornadoes &/or mesocyclones occurring simultaneously within an area roughly 12 miles on a side north of the Briscoe/Allison road.
Damage surveys are being conducted today, and an aerial survey may take place tomorrow (Saturday). We will post the results of the survey work on this email list, and we will post survey maps and details as part of the large volume of VORTEX data on the World Wide Web.
Finally, it should be noted that Chuck Doswell, chasing independently with Al Moller, obtained the best, most stunning tornado footage I have every seen. The footage was shot of a tornado moving through the south side of Pampa, TX, from a range of about 500 meters. This was a violent tornado that filled the sky with debris. There is no doubt that this footage should be tremendously valuable for tornado photogrammetry work.

Erik Rasmussen
Jerry Straka

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