Afternoon Towers, Twilight Flashes

May 10, 2013 by · Comments Off on Afternoon Towers, Twilight Flashes
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Seminole & Tecunseh, OK
15 Apr 13

SHORT: Struggling but occasionally photogenic convection near Seminole OK followed by lightning observation on back side of twilight storm complex.

LONG: During the day, a cold front had hung up along a weak frontal-wave low about 40 miles to our SE, closer than previously expected. While driving home from a dental appointment, which followed a day shift at work, two main things were on my mind–the Boston bombing, about which I learned at the dentist, and the towers going up on that boundary, visible to the SE.

Storms were more palatable to contemplate than the other grim issues of the day, so I headed home and picked up Elke for a short trek E. The better environment for photogenic, diurnal supercells was in north-central TX, NW of the Metroplex; but that was too far to reach before dark. We were hoping the cap could break closer to us, along an increasingly well-defined inflection point that lay nearly stationary over the area between Wanette and Konawa. That point also corresponded to the intersection of the frontal zone with a confluence line extending behind it to the NNE, and was persistently focusing the deepest (albeit still cap-dominated) buildups.

This part of Oklahoma is hilly and moderately forested, so high spots with good visibility are rather scant. During the couple hours or so before sunset, we waited at two places along US-377 S of Seminole–one right on the boundary, and another just to its N with better visibility. From the first, we saw one Cb erupt on the inflection point, briefly acquire strong radar reflectivity, then tear off to the NE, along the confluence line but also on the cold side of the boundary.

From the second stop, closer to Seminole, we photographed intervening towers with crepuscular rays, as a newer storm developed to the SW. The second Cb approached, skinny and pockmarked with holes, but beautiful to behold nonetheless. That likewise withered, so we headed into Seminole to grab some fast-food dinner and await further developments.

After supper, we saw a multicellular cluster forming back on the frontal wave and inflection to the SSW, and decided to get on the NW side of it for sunset color. Several cells emerged from that mess, including:

1. a sunset-illuminated left mover W of Tecumseh,
2. a right-moving supercell that we actually blew off because of its positioning on the dark side of the cluster, and
3. another left-mover to our E that was buzzing with a lot of in-cloud lightning discharges. The sky actually was darker than the photo makes it seem, due to the length of the exposures. Still, I wanted to strike that fine balance between bringing out the convective structures while not exposing for too long and blurring cloud features on a fairly quickly moving storm. How quickly?

Since then I’ve created a time lapse of the tripodded lightning shots I was attempting, so that you can gain some appreciation of the beauty of the third cell as it cruised fairly rapidly across the twilight skies to our SE. Please enjoy it. The time lapse spans six minutes, so you can see the fairly fast translation of the storm. Dial the speed meter up to the max level for full effect.

It was a mild, beautiful evening to watch the dynamic sky!