Cumulonimbus Barfus Maximus Nebraskus

June 10, 2006 by
Filed under: Summary 

Southeast WY, West NE and Northeast CO — 10 Jun 6

SHORT: Long drive for a little bit of good photography, a short-lived/high-based supercell near BFF, no legit tornadoes, and a lot of dusty outflow between east WY NE Panhandle and NE CO. Abundant small hail found after isolated high based storm near Cope CO.

LONG: Although there was enough shear for supercells (and we did see one), one of my fears was that the large scale ascent ahead of the west WY trough may arrive too soon. It did.

At noon MDT, the sky over east WY (behind the dryline-like surface feature) began filling in fast with high-based, fuzzy storms all-quadrants. The first of many of these was visible as we headed into Lusk WY, at 12:26 p.m. MDT (looking SW). Note that time, dear reader. That’s too blasted early!

Soon, more high-based storms formed all around east WY, spewing some beautiful CGs but also a lot of cold outflow. This is when the realization hit that the chance of seeing a legitimate tornado for us today was near zero. A patriotic, red-white-and-blue windmill framed one neatly lit cell S of Lusk, and then it was off to the races to get and stay ahead of the outflow.

Turning ESE out of Torrington, we noticed a high based storm distant ESE, near BFF, with a broad, shallow wall cloud. [No photos…I was driving, it was distant and did not impress me from that angle.]

As we crossed the Nebraska line, the pretty lighting of the arcus behind us caught our interest more than the high-based supercell near BFF, and we stopped to get some panoramics of the former (looking W and the companion shot looking WNW).

A few miles further down the road, near Morrill, we heard that the lofty little supercell to our ESE was TOR warned! It did have a legit meso that wrapped some precip filaments around its W side, but there were three problems:
1. A base way too high,
2. Undercutting from its own storm scale outflow, and
3. A building, mesobeta scale outflow surge about to smash to smithereens whatever remained of the storm.

After turning S from Bridgeport toward SNY we noticed a pronounced blocky lowering with a pendant, conically shaped cloud feature centered beneath. The problem was: It was behind the arcus cloud, made of thick scud, and not rotating. Shortly after that we passed some chasers parked nearby, atop a hill, on a side road. Elke said, “Somebody’s going to report that as a tornado.”

She has a keen sense for the presence of incompetent observers, because not 30 seconds later, the NWR alarm sounded with a tornado warning…for that storm, based on “spotters reported a developing tornado” in that very location. We pulled over and I took a few documentary photos of the sorry excuse for a “developing tornado” as it quickly devolved from solid scud into ragged garbage, then went away. The whole feature lasted less than two minutes and was about as tornadic as hoarfrost on the beard of a buffalo.

We stayed to do some equine photography with the arcus in the background, in a classical Great Plains scene. A herd of very friendly horses, initially on a hilltop about 1/4 mile away, galloped right over to beg our company and, in one case, vigorous human scratching of its apparently itchy forehead. Their company was all too brief. Within minutes, the gust front that had been several miles away overtook us with thick choking dust, 58 deg F surface temps, and howling NW winds — ahead of the arcus. Horses and humans cleared the area in a hurry.

Meanwhile the “tornado” warning suddenly vanished from NWR. Imagine that. “Developing tornado” — my _ss! Whoever reported that needs to go back to basic spotting class to be taught that tornadoes actually do rotate. Oh, and they don’t tend to occur behind arcus clouds rising over deep, cold outflow. Duh.

Southward to Sidney we cruised, stopping briefly to look at the visual manifestation of a LEWP off to our NNE. Now, on rare occasion, *those* sometimes spawn spinups, but this one got undercut so fast it didn’t have a chance. Maybe others up the line toward Cherry County did, but we had no interest in racing east for hours across NE trying to keep ahead of a deep, mesobeta scale (and growing) blob of surging outflow that felt like some weird mix of Saharan particulates in Antarctic katabatics.

“Spotters report a line of thunderstorms capable of tornadoes” was the last thing we heard from that NWR as we roared off into NE CO, trying to find isolated development S of the horrendous pile of outflow. Dusty gusts near SNY may have been severe, causing us to struggle to stay on the road at times in a heavy, low-profile sedan. That said, I won’t venture an estimate since neither my estimates nor anyone else’s on this planet are reliable to within +-20 kt at those speeds.

N of Sterling we passed what appeared to me 5 or 6 TTU mobile mesonet vehicles and, just a little ways down the road, a non-DOW portable radar (Howie?).

We did intercept the back side of a small SVR-warned Cb near Cope that had a pretty backshear as viewed from the N, but also, a very high base. Precip curtains prevented us from viewing the updraft region until we let it get SE of us, and man, was it ever high based. A good deal of hail that was marble sized (but conical or candy-corn shaped) covered the ground along US 36 in the Cope/Joes area, on both sides of the Washington/Yuma County lines.

We ended the storm day with some dinner in Limon, and photography of the old grain elevator under sunset-lit ACCAS. Cold NNE winds soon blasted us there, two hours and 100 miles removed from our last encounter with the same outflow current near Sterling. Even in the north suburbs of DEN, after 11 p.m., we got a shot of the outflow pool sloshing in from the ENE. That gave us nearly 12 hours in and out of outflow from the same huge mess of storms.

===== Roger =====

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