Blobulus Barfus Windbaggus

August 21, 2008 by
Filed under: Summary 

All-Afternoon Stern Chase
SW Nebraska and NW KS Outflow Dominant MCS

18 Jun 8

SHORT: Unsuccessful (if inflow view is the goal) stern chase of HP-turned-MCS and later tail-end supercell across SW NEb and NW KS.


Elke and I lingered too long in AIA over lunch and got a late start, driving S then SE away from some junky midday convective development near AIA and beneath a large plume of middle and upper level clouds. The goal was a forecast target zone around SNY-IML. Even as early as late morning, that area looked very good for a starting point, given

  1. Subtle, SSE-NNW oriented outflow boundary from west KS across NErn CO to near SNY,
  2. Newer outflow boundary from early central NEb MCS, extending Wward across southern Neb into the same area,
  3. Moist axis between them, under
  4. NW flow (to enhance deep-layer shear) for the third of five consecutive storm observing days for us

As we moved S toward SNY, the target area changed slightly eastward, away from us, as a thick chunk of occasionally precipitating mid-upper level clouds (associated with a weak shortwave trough ejecting SE from the mean ridge) shaded most of the southern NEb Panhandle. The differential heating zone, evident along the S edge of this cloud mass, coincided well with a low-level convergence max, into which the surface map showed a SE-NW aligned moist axis. Slam dunk for an easy target, right? Sure! Problem was, we were behind it. My laziness in bolting AIA cost is a shot at getting ahead of the huge HP storm that erupted with astonishing speed right in that area, near OGA, then moved SE across Perkins County and the MCK area.

In the meantime, the big backshear of the anvil provided us with some cool views from the wrong side, as we rounded Lake McConaughy. We wanted to shoot the gap between the growing complex and an inexplicably blanket-TOR-warned line of storms to its SW that didn’t look too impressive to me. [I thought tornado warnings were supposed to be storm based, targeting a small polygon in the path of the mesocyclone, not blanketing an entire line when only tiny fractions of said line ever could/would produce a tornado. So while she was driving, Elke had to listen to me express some rants that basically reflected much of the same befuddlement that I later heard from other seasoned storm observer-meteorologists.

That strange circumstance aside, we stopped briefly to admire a clean, post-MCS convective scene beyond young corn, N of IML (looking SE). Notice in that shot the corn leaning left to right — meaning a NE wind. That was outflow, which we never escaped S of I-80 on this day except for a very brief advance ahead of the boundary at Colby. We finally gave up on catching the HP/bow/MCS mess when we hit Colby, and got a room — as the boundary whooshed through town. At least one advantage of driving so many miles through outflow is that we didn’t need to use the car’s air conditioning. Nature provided that.

While unloading in our room, I noticed that a storm that blew up along the trailing outflow boundary — in the next county to our ESE — quickly developed a hook and a meso. Could this be another post-hotel, near-sunset chase rebirth, for the second consecutive day?

Unfortunately there also was a mess of nonsevere mush forming to its own SW, ahead of as well as along the outflow boundary. We bolted SE on I-70, but still couldn’t catch up, at least not at safe driving speeds. The storm merged with the mush, and we easily could have taken a demoralized, tail-between-legs retreat back to Colby.

Instead, we found solitude and solace in a big wheat field a couple miles S of Grainfield, bisected by a dirt road upon which nobody traveled in the hour or more we were there. Our company was each other, along with the cool, moist east wind, carrying the call of western meadowlarks, pheasants, and horned larks. We shot quite a few photos of the chaotic sky behind the retreating MCS, its clumps and rings of mammatus, and other sky scenes across the waving wheat, finally leaving shortly after sunset.

Strategically, this was a failed chase attributable entirely to slothful behavior on my part, and a self-made supercellular bustola of the first order. Making a good forecast doesn’t help when you don’t get your butt there in time. But we ended up salvaging something from it all, and went to sleep that night at ease by that.


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