Messy Quail TX Supercell of 23 Feb 2007
Filed under: Summary
Rich, Ryan and I (with Ryan driving) left AbNorman around 1315 LST with a general target area of CDS-Wellington, via LTS. Ryan set up a laptop in the front seat with internet-connected laptop via cellular telephone, so we had access most of the time to satellite, surface, upper air and radar information. This was an unusual experience for me as a storm observer. As you’ll read, it didn’t help us find the funnel or see the one certifiably tornadic storm, but we still had a nice, early-season, tune-up chase.
After we left, the area near the Caprock and E of PVW exhibited a large, dense clump of Cu, which we figured eventually could spawn some convection. I had serious doubts about getting any storms at all before dark, but when that agitated area formed and persisted, those concerns gradually faded. We met up with Sheriff Greg at the 62/83 junction S of Wellington and waited for half an hour or more as Cb began forming from that agitated area NNE nearly to I-40. We had daytime initiation! Several towers and small Cb became visible, three of which took over:
1. NORTHERN STORM: Looked best early, both on radar and visually. Here’s a zoomed view looking WNW from the 62/83 intersection. In this view one can see a horseshoe vortex filament at upper middle. This storm projected toward northern Wheeler County and was easily interceptable by roaring N up 83, should we have chosen. A panoramic shot shows the young northern Cb. We began to head N to stay in position for this one, while remaining able to play the other two in case Storm 1 died. When it started to crap out, while we were a few miles N of Wellington, we turned our attention toward the most vigorous development (Storm 3, Southern).
2. MIDDLE STORM: Looked the most fragile, disorganized and puny of the three for the longest time, but ended up being the longest lived and the only inarguably tornadic storm (the one funnel with confirmed dust/debris whirl, seen by R. Hill near I-40). We had a slightly better angle on the southern storm (below), and like others, were concerned about its relatively weak looking structure and potential interaction with a left split from Storm 3.
3. SOUTHERN STORM: By far the most robust looking during daylight hours. While sitting N of Wellington, we decided to intercept this one, by going to the Quail area and waiting for it to move to us as it matured. Here’s how the storm looked from the NE as we began maneuvering for position N of Wellington. [Remember that the late sun still is to the SW this time of year, placing it behind the storm from that perspective.] Note the stable stratocumulus billows between us and the Cb! We were on the E edge of the narrow corridor of favorable sfc-based buoyancy, at the time.
As we approached Quail, the storm began to take on a supercellular appearance on reflectivity imagery, though our eyeball view was obsecured somewhat by intervening forward-flank precip. As we approached Quail, our view of the SW horizon continually was blocked by — of all things — [i]trees[/i]! This problem remained all the way past a point 2.5 WNW Quail, where we finally decided we had gone far enough W to be almost directly in the path of the strengthening mesocyclone (by then, 90-100 kt horizontal shear). This view is fairly representative of our visual perspective as the storm approached. Looking toward the SW, you can see the anvil edge, an intervening billow cloud band, and a more distant band and relatively precip-free base.
Several doses of forward flank rain moved over us, but the precip remained sufficiently translucent to permit view of the potential action area. We got impatient with the storm, however, and tried to get S of Quail for a better vantage. This cost us our chance to see the brief funnel(s), which apparently happened as we were turning S out of Quail, repositioning.
Trees and terrain blocked a continuous view of the base until we found a suitable parking spot about 3 S Quail. By then, we could see the mesocyclonic cloud base and visible cyclonic shear, located in between precip areas and behind the clear slot in this photograph. [The white stuff in the field is cotton, not hail, though we did get some marble and smaller size hail for a couple minutes shortly after that photo.] The heavier precip at left began wrapping S, SE then E of the meso, as if in a hook configuration.
The sun had set and the light was getting very low. A few “scudnado” teasers appeared under the cloud base in the meso area before we let the storm go. I had some interest in the wrapping precip area at left in the latter shot, but the only thing I could ascertain (contrast enhanced crop) was simply heavier precip-in-precip. With a storm characterized by a low frequency of CG lightning, we knew any decent window of viewing was closing fast (looking NW at the wrapping precip), and we soon let the storm pass off to our N and NE as it evolved into a small bow.
Did I think there would be tornadoes before dark? No. My forecast was wrong from a deterministic perspective. In a probabilistic sense, my forecast wasn’t too far off, with only one certain tornado (McLean, Storm 2) and a maybe-nado (Storm 3, ours), immediately before sunset.
Nonetheless, the atmosphere itself — the ultimate answer key to any forecasting test — ended up verifying a zero sig-tor probability, and zero total-tor probability everywhere east of the TX/OK border. There was no sig-hail reported at all in TX/OK, no sig-wind at all anywhere, and indeed, only 3 wind reports total. For such a kinematically intense system, this event was a grotesque underperformance (or overforecast, depending on how you want to look at it). Much of the blame, IMHO, can be placed on the crappy thermodynamic support in the boundary layer, outside that narrow little sliver of the eastern Panhandle, then in the failure of surface-based destabilization after dark on OK to occur strongly enough to develop effective inflow parcels rooted at or near the surface.