Tri-County LP

May 8, 2011 by · Comments Off on Tri-County LP
Filed under: Summary 

Newcastle OK
8 May 11

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

LONG:
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.

Fun with Small Nebraska Panhandle Supercells

July 14, 2010 by · Comments Off on Fun with Small Nebraska Panhandle Supercells
Filed under: Uncategorized 

Harrison-Gering NE, 19 Jun 10

SHORT: Intercepted 3 nontornadic supercells in Nebraska Panhandle, one after dark near BFF.

LONG: A cold front had swept out of the Dakotas following our last storm intercept day. That stabilized the air mass for awhile and gave a couple of non-chase days for laundry, sightseeing, relaxed travel SW toward an eventual central High Plains target area, and photographing abandoned buildings of various kinds over the Dakotas and western Nebraska: an old schoolhouse, a long-disused, small-town rail station,a barn, the back door of another barn, a mostly intact farmhouse, and a gradually collapsing old house looking in and from without. Elke and I hadn’t been back in the Dakotas for a few years; and while storms beckoned us away, it was great to see the northern Plains again, especially in such a verdant, moist state.

The front’s trailing remnants stalled across the central High Plains beneath favorable mid-upper flow for supercells, while easterly and southeasterly flow to its N would yield decent low-level hodographs. A textbook, multi-day, central Great Plains upslope pattern was setting up, and we had time to participate before the chase season closed out. The main concern on this day was a lack of more robust moisture, but I wasn’t concerned much about whether we would see a storm form, given favorable upslope flow into the higher terrain of eastern Wyoming. We left PIR by mid-morning, targeting the Wyoming/Nebraska border region, with a short venture into the whimsical (but fun) tourist trap of Wall Drug.

As we left Wall Drug, convective towers bubbled over the Black Hills, but struggled amidst the lack of moisture. Moist advection started to solve that problem by the time we got down to around Harrison NE, with a discrete storm erupting to our SW over eastern WY and a short line of some overshooting cells to our NW (closeness exaggerated in the zoom view) across northeast WY, W of the Black Hills. Although both eventually would yield supercells, we went for the cleaner, more moist target to the SW.

We found a one-lane dirt road between Agate Fossil Beds and Mitchell, off NE-29 — no crowds, no traffic, nothing but us, a vast rolling prairie, a storm organizing into a slowly moving LP supercell, and dozens of different bird species joyously singing across the mild breezes.

The chase season to date, and the vacation in particular, had featured lots of driving and moderately- to fast-moving storms. This was a most welcome relief! We stayed there for nearly an hour, just enjoying the peace and solitude, punctuated only with an occasional rumble of thunder from the small, high-based supercell. It didn’t matter at all that this storm likely could never produce a tornado. The soothing salve of the Great Plains in springtime worked its rejuvenating magic on us, and we experienced the most pure, relaxing enjoyment in the face of a storm all season so far. It was a deep-tissue massage for the soul, a reconnection with why we’re out there to begin with.

I also, finally, had a chance to set up our new HD video camera on a tripod, and let it stand there and roll (our first video shooting in several years). [I eventually will construct some time lapses from this footage.] We had received this as a gift shortly before leaving on our trip, and I hadn’t really had a chance to learn how to use it right, amidst all the more active chasing we had done so far. The main intent of this video camera will be to shoot HD time lapses for our own enjoyment and perhaps uploading online; but first priority will be still photography. In this case, our video will feature a chorus of birds in stereo, the breeze, and an approaching storm.

As the first supercell grew more feeble, another small storm erupted very nearby to its S (and our SW), upon which I re-aimed the video and still cameras. This wide-angle shot shows both cumulonimbi at once, and illustrates how neighborly they were. It’s as if one was asking the other, “Would you like to come in and sit a spell? I’ve made some fresh lllllll-lemonade!” (quote [tm] Ryan Jewell). Instead, the northern storm shriveled to vaporous oblivion, leaving the southern one to spin along for a little while NW-N of Mitchell (and by the time of this shot, SSW of us). We finally decided to head S before the storm crossed NE-29, reserving a motel in the BFF suburb of Gering (which wasn’t easy due to all the hail-claim adjusters in town), packing the tripods, and beating the thin hail core across the road. This second supercell soon raised its base and weakened (view looking NE from a few miles E of Mitchell). It was time for some supper in nearby BFF.

As we dined, convection began popping up all around, almost at random, as if a pleasurable rash. Most of it was weak and inconsequential. One storm, however, took good root and became dominant to our WSW. We had some trouble finding the place of lodging we had reserved in Gering (in a neighborhood just W of downtown, but also just a few blocks from the entrance to Scotts Bluff National Monument, as it turned out to our good fortune). After we checked in, we headed over the hill S of the bluff to watch the now-weakening storm move in from the W. Its lightning slowed down dramatically as we set up tripods (of course), but not before one spectacular spark sliced through the twilight sky beneath for sloping base of the forward-flank anvil area. We also enjoyed seeing the apparently dying supercell’s remains float overhead beneath the moonlight, then headed back to our room.

While we were inside, unpacking and unwinding, I noticed lightning activity picking up outside. Another storm? No…after we gave up on it, the supercell rejuvenated and drifted just to our N over BFF, sparking anew from within! Out the door and right back up the hill we went, this time on its E side, to watch the spectacle. Once again, as we got set up, it weakened, but not before producing some nice intracloud flashes around a moonlit main updraft tower that was drying up from below.

I didn’t think to bring the new camcorder back out, and hadn’t yet tried the video functions of the 5DM2 still camera. So, instead, here’s a poor-man’s time lapse I constructed of still photos of the weakening storm moving away from BFF, where it had dumped hail up to baseball size. More work for those hotel-hogging insurance adjusters!