Tri-County LP

May 8, 2011 by · Comments Off on Tri-County LP
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Newcastle OK
8 May 11

SHORT: Right-split LP storm an easy drive W of Norman

Dryline storms seemed a long shot, given the intensity of the elevated mixed layer and the stout capping implied by the morning soundings. High-resolution, convection-allowing models such as the HRRR showed nothing in their reflectivity forecasts. Still, models can be wrong, and deep thermals clearly were likely with surface temps soaring past 100 degrees F on the W side of the dryline.

while doing assorted errands and chores domestically, I kept intermittent watch on the dryline located a tantalizingly close distance to our NW through SW. By mid-afternoon, a string of large, high–based cumuli developed from S of I-40 in OK southward past the SPS area to ABI, the nearest robust area of convective agitation being SW of CHK. After several images, some of those towers began to glaciate, with reflectivity echoes appearing on both FDR and OKC-area radar scopes.

To hell with convection-allowing models…the real atmosphere had decided otherwise! Therefore, I decided to go W a short distance for a peek at the storms.

The first (easternmost) cells near CHK, that had prompted a severe thunderstorm warning, were dying; but by the time I arrived just SW of Blanchard, a new set of splitting left and right movers was underway to my WNW, W of Minco. At first the left-moving storm seemed dominant; but I knew the right-mover should take over if it could survive the capping, given favorable deep-layer shear, increasingly curved low-level hodographs and about 200 m2/s2 of effective storm-relative helicity.

And so it did. As the left-mover got fuzzy and shriveled, and as I moved to a position several miles NNW of Newcastle, the right-split ( here seen to the W) sported a vertical wall on its N side. I let the storm move toward me (and slightly to the N), watching the base expand but become a little more ragged as it did. The storm kept cruising to the ENE toward southern/central OKC, and weakened. Convective inhibition was proclaiming its dominance over convective processes! End of intercept.

On the way back, I drove trough that art of western Moore that contains no trees greater than 12 years of age. Today’s leisurely storm-observing jaunt was a monumental contrast to that day twelve years and five days prior, thoughts of which flooded my mind as a testament to its memorial indelibility.