Saturday, March 30, 2013 (Southwest OK, 205 mi.)


Marginal supercells in light northwest flow show off a few photogenic scenes.

Observed hail to quarter size.

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Despite an airmass with seasonably respectable low-level theta-e residing over the southern Plains, initiation was quite uncertain today owing to a lack of forcing. An early impulse in the northwest flow resulted in several supercells over the Arklatex by early afternoon, so I suspected we might be victim to shortwave ridging through the remainder of daylight farther west. However, by the 5pm hour, a stationary boundary draped near I-44 began firing off updrafts. The first developed over the Wichita Mountains, so I immediately took off down I-44, anticipating a southeasterly storm motion (and likely good structure, given the directional turning).

For the second day in a row, low-level hodographs were small and lacking in curvature, so it was no surprise to see frequent splitting with today's supercells. As I passed Chickasha, the anorexic left split of the WMWR storm loomed to my WSW, with decent mammatus beneath its east-southeastward-extending anvil.

Storm motion was quite slow for the right split; reports of 2" hail on the west side of Lawton had come in before I even made it to Chickasha, yet as I finally drove through the east side of Lawton on I-44, I still managed to avoid any stones. I stopped at the Geronimo exit, where I could finally see the structure without harsh backlighting. It was a bit underwhelming owing both to high T/Td spreads and what appeared to be a capping layer, but I stopped to snap a few photos.

I quickly decided I'd need to continue S in order to keep the full storm in view, so I pressed on to the gas station in the median of I-44 near Walters. From there, I captured more mediocre structure that was redeemed somewhat by magic hour lighting.

The supercells both yesterday and today have exhibited a very "pulsey" behavior; they'll repeatedly come close to dying off completely, only for a new updraft pulse on the upshear side to revive them. This happened at least 3-4 times while I "chased" the Lawton storm. I decided I'd had enough as the last light began to fade, and the storm looked to be on its last legs both visually and on radar. I casually started back N, only to encounter quarter size hail a few miles NW of Walters, as yet another updraft had risen from the storm's ashes. I exited again at Geronimo to watch the cell in twilight from the north side, where I was able to get a few lightning shots. I'm looking due S in these photos, and repeated new updraft pulses can be seen on the west (right) side.