Archives for November 2, 2008

Looks like the Great Plains and Midwest may get one last crack at severe thunderstorms later this week. I”m crossing my fingers and hoping that the Great Lakes will get a decent show of that energy, but I”m not counting on it. The SPC indicates the low weakening as it lifts into our area, and it looks like whatever makes its way here will be a linear show. So my best bet might be to head west Wednesday and chase the cold core. Having already traveled to and from Branson, Missouri, this last week, I”m not crazy about the idea of another long road trip, but if I can find someone to join me, I might consider it. We”ll see.\r\n\r\nSpeaking of Missouri, I had one of my first truly memorable chases there a couple years ago, back on March 12, 2006. That was the day when Bill Oosterbaan and I latched onto a monster tornadic storm near Columbia that would go down in weather history as the Six State Supercell. From its origins as a convective plume in Noble County, Oklahoma, to its demise in Jackson County, Michigan, this beast set a record for distance and longevity. Covering over 700 miles in seventeen-and-a-half hours, it spawned more than twenty tornadoes as it raked portions of Oklahoma, Kansas, Missouri, Illinois, Indiana, and Michigan.\r\n\r\nBill and I first closed in on the storm shortly after it produced a half-mile-wide tornado in Sedalia. We had already encountered another tornadic supercell directly to its north, but opted to leave that one in favor of the tail-end Charlie to its south. Heading east down I-70, we got ahead of the storm, then exited on highway 63 in Columbia and positioned ourselves on the shoulder just south of the ramp.\r\n\r\nFrom our vantage point, we watched the storm move in. Videography has never been my strong suite, and in those days I was brand new to it and made all kinds of glaring errors. My early storm videos include generous portions of shaky zoom shots, inane commentary, grainy low-light footage, beautiful close-ups of my kneecap due to my forgetting to turn off the “record” function, and fuzzy images as the auto-focus failed to settle in on its subject. Nevertheless, there in Columbia I managed to capture a storm feature that at first glance appeared to be just a suspicious-looking rain band, but which later review confirmed to have been a large but poorly defined and brief tornado west of town.\r\n\r\nAs the storm closed in, we dropped south a bit and let the mesocyclone pass just to our north. Then we hopped back onto I-70 and blasted east with the storm. As the cell lifted northeast, we left the Interstate and hit the winding country roads, driving like madmen in a desperate attempt to keep up with the storm. Amazingly, we succeeded.\r\n\r\nThese were my pre-GR3 days, when our only radar source was the NOAA site. We didn”t know enough to know how little we knew. We had only just grasped the significance of the velocity readings, and this expedition was our first application of them. Not knowing the difference between base velocity and storm relative velocity, we resorted to base velocity.\r\n\r\nStill, despite our unsophistication on the radar, we could tell both visually and on the radar screen that our tail-end Charlie and the supercell immediately to its north were two impressive storms, each displaying a beautiful hook. As we crossed the Mississippi River into Illinois, the cells began to merge and the lightning increased dramatically from intense to incessant. Absorbing its northern neighbor, our storm gained strength as it stalked northeast across the Illinois flatlands toward Springfield.\r\n\r\n(To be continued.)