Cyclone Road

Sunday, July 06, 2003

South Dakota today
O'Neil, Nebraska- Headed to Aberdeen this morning, though I think a second area of supercells could form near Omaha in Eastern Nebraska. South Dakota has a slight advantage in terms of proximity to upper level energy and lift ahead of the shortwave aloft. Windfields are about the same--maybe a little better LLJ in Nebraska. Cap is stronger south of course, and it would be closer to home, but I've never been to either Dakota and am interested to see it.

Chasing Droids With the Sandpeople
O'Neil, Nebraska--Mike Hollingshead and I watched some impressive supercells this afternoon from south of Valentine, Nebraska through Brown County to near Brewster and towards Burrell. We kept near the east to west boundary along and near State Road 91 until it was obvious things were going north explosively, then we closed on the storm as it moved from South Dakota into Nebraska. Mike suffered a rougue baseball hailstone from a small storm that erupted in between the Cherry County and Holt County supercells. This small cell grew rapidly and moved north, strangely enough, and though we laughed at its size and gumption (an elevated wall cloud at one point) it dropped a symmetrical, cyclonic shaped fracture on Mike's windshield.

At one point, just north of Brewster, we stayed and allowed the storm to pass over us when we were convinced it had gusted out and weakened. We'd observed some minor regeneration of the mesocyclone twenty minutes earlier, but as the storm passed our location on State Road 7, it looked relatively innocuous. Just as the 40 knot winds and small hail began driving across the road and rocking our vehicles, the tones sounded on NOAA radio for a new tornado warning on the storm. When the core passed us we turned to observe wrapping rain curtains to our east, and a powerful new updraft tower.

Neither of the two supercells we observed threatened to put down tornadoes, but were beautifully striated and marble-white updraft towers showed particularly well against the cobalt blue sky and tall green grass of the Nebraska sandhills. A beautiful, strange country--though the road network leaves a lot to be desired, and was the reason we could not intercept the Holt County supercell which reportedly dropped a tornado near Ainsworth.

We expect to go north tomorrow, though not sure how far. Roger's 6Z makes it sounds like a trip to Canada is in order. I've never been to South Dakota, so I'm looking forward to a new state.