Green Sky Chaser

23 February 2007 Chase Log


Target Area: Lawton/Altus, Oklahoma to Vernon, Texas

Chase Area: Hollis, Oklahoma to Shamrock, Texas

Observations: one wall cloud, one supercell, and lightning

Distance: 500 miles

Time: 10 hours

Chase Team: Car 1 - Esther White and myself; Car 2 - Joe Daron, Gemma Ebsworth, Ryan Surrage, and Duncan Geere

SPC Convective Outlook: Moderate Risk (Click to see SPC products, data, and storm reports)

Chase Setup: Shortwave trough over the Four Corners' region. Temperatures in the mid– to upper 60s in southwest Oklahoma and much of Texas. Dewpoints in the mid– to upper 50s in western Oklahoma and Texas ahead of a dryline in the central/east Texas Panhandle. CAPE of about 1000 J kg-1 in the east Texas Panhandle. Good wind shear for supercells, with helicity of 300 m2 s-2 in the east Texas Panhandle and southwest Oklahoma. Strongest wind shear mostly in central into eastern Oklahoma and Texas.

Chase Log: On the Brits' first and my sixth storm chase (everyone I was with on this chase was an exchange student from the University of Reading in England), and the first storm chase on which I was driving my own car and responsible for making many of the decisions (and yes, it was exciting but a little scary), we first headed off to Lawton. The best wind shear, moisture, and some of the best instability appeared to be in that region. However, the best lift and even better instability could be found closer to the dryline in the Texas Panhandle. We stopped at a Best Western to re-evaluate.

A tornado watch had just been issued for western Oklahoma, the east Texas Panhandle, and southwest Kansas. We drove west towards Altus on Highway 62. By the time we got to the Texas border, three supercells had already formed along Highway 83 to our north.

We snuck up on what I believe was the southern cell, and saw a well-developed supercell with a nice wall cloud near Quail and Wellington, Texas. By the time we reached the supercell, about all we saw was the wall cloud and some cloud-to-ground lightning strikes.

The supercell had already produced two tornadoes, at about 6:11pm and 6:18pm, but we didn't get to the wall cloud until about 6:40pm. It was a little sad that we missed out on a tornado by some 20 minutes or so, but it was still an exciting and fun chase - especially since it was one of my first few chases and everyone else's first chase. The storms and tornadoes really did form in the perfect environment; it had the best CAPE, just about the best wind shear, decent moisture, and they were right along the dryline. Can't get a much better Texas Panhandle day than that! Except, of course, our next chase, which proved to be even more successful....