Cumulonimbus Shrivelus Patheticus

August 19, 2009 by · 2 Comments
Filed under: Summary 

North-central OK, 19 Aug 9

SHORT: Promising young storm E of END shriveled as I reached it.

As the day wore on, it became progressively more apparent that some supercell potential would exist this afternoon along and N of an outflow boundary retreating N across central and NW OK. An unusual amount of mid-upper level winds for August spread over the area — 35-40 jt at 500 mb, with strongly curved and enlarged hodographs N of the vorticity-laden outflow boundary. It looked as intriguing as many late May or early June setups, ignoring the fact that the calendar read, “August.

I took the pickup to work for the first time today, and hadn’t yet equipped it completely for a storm intercept. While at work, Elke brought my handheld live radar and weather data module (i.e., I-Phone), and I borrowed an Oklahoma road atlas. She couldn’t chase and neither could Rich; and my shift ended an hour after others’. So it was just me this time, incognito in a pickup much like those driven by tens of thousands of other Okie residents on any given day.

Cumuli already were deepening in a persistent, agitated area of ascent along the NW limb of the old outflow boundary, in major and Blaine counties, before I left. Already equipped with camera gear, as usual, I took off straight N up I-35 as soon as the shift ended (5 p.m.), figuring the projected 20 kt eastward mature supercell motion would allow me to beat any storms that formed in the agitated area to I-35. Rich was impressed enough to issue a tornado watch, which seemed good to me.

Unfortunately, the atmosphere that I thought was flashing a middle finger toward the calendar instead flipped me off. One Cb erupted NW of END, seemingly destined to turn E and cruise along or just S of the KS border. I would have been in time to intercept that but it dissipated quickly.

A second storm blew up near END, in ideal intercept position; all I needed to do would be to head up to the US-412 exit and let it come to me. So I did. On radar the storm appeared persistent, neither growing nor shrinking much, as if it was fighting some adverse effect but still hanging in there. The updrafts looked alternatively robust then soft, then robust again, giving the same impression of a delicate balance that could tip precariously to storm demise or explosively to beats-honking supercell.

What happened? The former! By the time I got to a parking spot just W of the exit, the storm was a “chicken neck” updraft, showing some corkscrewing motion but also shrinking by the minute (above image). A multicellular MCS was taking shape in southern KS, out of reach for both the amount of remaining daylight and my desire to get home. The “storm” wasted away within 15 minutes after my arrival, leaving me to grab a terrible chicken sandwich at the Braums in Perry and head back to Norman.

This barely qualified as a “storm observed this year,” but I did hear a couple of lightning pops on the A.M. radio. I’ve certainly observed less (i.e., no development at all) in a few big CAPE, ample-shear setups along well-defined boundaries. At least I didn’t waste much time or fuel, and I got to break in the truck for chase purposes. It was a comfortable and roomy ride.