Tornado Alley (PROG)

[F6]

hookrider -- that was quite a storm -- the setup was pretty unique -- not much of any wind or particular wind shear aloft, almost unheard-of with a supercell producing such a violent tornado -- but there were two nearly-identical surface/near-surface airmasses, one to the west and the other to the east, both quite hot [mid- upper 90s] and extremely humid but the one to the east even a bit more humid (dewpoints low-mid 70s in the airmass to the west, as high as the low 80s in the one to the east) -- both pretty strongly capped by the airmass farther aloft, with just the slightest bit of weakness in that cap running above the (very weak ambient surface convergence [S to SSW flow to the west, S to SSE flow to the east] along the) boundary (which I think I recall was the remnant of an outflow boundary left by storms well away from the area which had died out about a day and a half earlier) -- with that roughly north-south boundary between the two surface/near-surface airmasses ending up as the seam along which the storm initially managed to break through the cap and form, south of Waco, and then move south, effectively unzipping the cap aloft above the boundary as it moved down the boundary and allowing the extremely (CAPE exceeding 5,000 j/kg) unstable/energy-laden air from the surface/near-surface (on both sides of the boundary) to rise into the storm as its fuel -- once the storm got going, it just went right on down along the boundary following/moving into and ingesting more and more of that abundant and very rich boundary-layer fuel -- with the tornado itself as the leading point of the storm/that unzipping, the large body/precip core of the storm trailing behind; the tornado itself the core of the updraft feeding that fuel into the body of the storm