Surfing the Wake of the USS Hailbomb

June 29, 2009 by
Filed under: Summary, Uncategorized 

A Tale of Two Supercells
7 Jun 9
Pawnee City NEb, to Bethany MO

SHORT: Intercepted Pawnee City supercell for a spell, then failed in prolonged attempt to get around and ahead of the hail-heavy Oregon City/Savannah MO supercell. Interesting structure on both storms.

First off, we found out this day about the (non-weather related) road death in Iowa of storm observer Fabian Guerra. Though we didn’t know him, we offer condolences and sympathy to those who did. It was a simple but fatal deal of wrong-place/wrong-time that could happen to anybody who drives. Many of us in storm observing and outdoor photography have plowed into a deer (guilty here, twice) and/or swerved to avoid one, and simply were fortunate enough to maintain control of the vehicle and/or not have the animal come through the windshield. Never take tomorrow for granted!

As for the day’s chase… Elke and I headed for our target area of north central to NE KS — E to NE of the surface low and near the frontal zone. This was “synoptically evident” as they come, in the forecast sense; but mesoscale details (as often) threatened to mess up the chase day. Right as some of the best afternoon heating was about to take place, a thick plume of cirrus cast its deepening shadow overhead, an unwelcome visitor from above, wafted off a band of elevated, middle-level showers to our W and SW.

Despite this annoying development, no other area looked any better. Marysville, one of our favorite towns, seemed a good spot to wait for initiation, so we parked at the hilltop Wal-Mart for awhile in anticipation. The hail event the night before clearly was major, as shredded vegetation covered the ground throughout much of town, with windows broken in some houses and churches. DF and his cousin Samara (now the Two Fogels and Two Dogs chase team) joined us, as did a local spotter (Jamie) who followed us for a couple of hours.

Storms fired directly beneath the decaying remnants of the midlevel convection, in a short line segment from just NW of us (and over the NEb border) SSW to SW of Marysville. I’ll hypothesize that the cap, tremendously strong on the 12Z TOP RAOB, was weakened not only via columnar cooling related to large scale ascent, but also by evaporational cooling from above as the elevated, weak convection precipitated into the warm and dry capping layer.

One storm cluster — W of Pawnee City — seemed destined for good times, being on the boundary and in optimally backed flow; but it needed to shed the deleterious influence of junk storms to its immediate SSE. Meanwhile the tail-end storm (ahead of which we stayed for awhile) looked strung out and high based…a “wannabe” supercell. When the northern storm finally did lose its interfering garbage, it quickly acquired a deep meso and hook, so we targeted it. The tail-end storm fought disorganization for a couple hours, but would go on to become the V.O.R.T.EX.2-targeted Oregon City MO hailstorm.

Our Pawnee City storm gave us some good structure views through somewhat hazy skies, produced a few wall clouds (some weakly rotating), and even a nice RFD cut or two, but never could tighten up that well (wide-angle shot from 8 E Pawnee City, looking SW). We saw Chuck and Vickie amidst what he astutely termed the “cluster-f#&%” of chasers around that storm; there was so much traffic over a blind hill that I momentarily stood roadside to guide them into it.

Soon, the supercell began to get highly tilted and to shrink, while approaching the MO River, so we decided (perhaps a little too late) to leave it. Jamie the Marysville spotter, by then, left us to go home.

Meanwhile the southern storm, which we saw from earliest towers S of Marysville, suddenly was a somewhat sunlit eruption of thick, deep convection and anvil backshearing, beckoning longingly to us from its throne high in the southeastern sky. I never had much luck stern-chasing supercells in northern MO, given the hilly terrain, narrow and curvy roads, untimely towns and slow local traffic. Nonetheless, with a couple hours daylight left and some convincing from DF, we tried anyway…

Hard as we tried, with the river crossing and a tortuous maze of indirect, winding road options, we simply couldn’t get ahead of it without core-punching a rotating wall of hail that was visually apparent around the back of the hook. The hook seemed to park itself on every east road we wanted to take, right before we got there.

At one point near Union Star, a “bolt from the blue” struck less than half a mile to our S, several miles behind the hook and the flanking line. Less than twenty seconds later, we pulled over and I was outside shooting this image of a hailshaft on the backside of the supercell…but not for long, lest the storm recharge quickly and fling another supercharged bolt our way. DF and Samara must have thought I was nuts doing this just a couple of blinks after seeing Zeus’ pitchfork plow into the earth nearby. There was some risk, but probabilities were on my side if I didn’t linger too long out there.

While zigzagging constantly astern of the heavy frozen-cargo vessel USS Hailbomb, as if dolphins surfing back and forth through its wake, we indeed did see some huge stones (greater than baseball size or at least 3 inches diameter). The gorilla hail lay in the grass at Oregon MO amidst shredded vegetation, but we didn’t stop to measure due to the continuing chase.

We finally got near the back side of the hook near Maysville, taking decisive visual measure of a churning merry-go-round of rain and hail curtains orbiting some unseen circulation center to our immediate east. With tornado reports (even if they later turned out to be bogus “sheriffnadoes”) coming from inside that bear’s cage, we decided not to punch through. Instead, at sunset, we finally took the long way around, down to US-36 to Cameron and up I-35 a few miles toward Bethany, but still couldn’t get ahead. That’s when we waved the white flag and let the storm march off into the northern Missouri night.

Some attempts at lighting shots ensued (a decent but not outstanding one, and a better opportunity that I slightly overexposed, unfortunately), along with some conversation with Alnado there, and we headed back toward lodging at STJ. Along the way W on US 36, a dense flock of heavy storms developed atop the supercell’s outflow, coring us repeatedly with blinding rain and intermittent small hail.

A pretty decent chase day was capped off by finding a live brown recluse spider in our room at the Super 8 in St. Joseph (where Charles, Rocky, Bill Hark, Dave Lewison and other chasers also were staying). One of the girls staffing the front desk was frightened almost to panic by it. The other took it in stride, saying, “Oh yeah, we’ve got those all over our house.” At no point did either of them think to apologize or offer comps to this particular customer. I fed the fiddleback to a black widow spider from Oklahoma (my yard, specifically) that DF was carrying around as a sort of chase mascot this year. I also talked to a truck driver in the lobby who had lost all his window glass to what he estimated to be softball sized hail at Oregon City earlier in the day.


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