Sunday, July 06, 2003
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.
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.
Saturday, July 05, 2003
vapor loop, though I've had a bitch of a time downloading one. Convection this morning in northwest and northcentral Nebraska has complicated the picture but ultimately may only reinforce the surface boundary currently along the Neb/Kan border. As that lifts west and interacts with various outflow boundaries, storms should fire when the s/w arrives. I hope. Right now my target is between Broken Bow and Brewster.
Thursday, July 03, 2003
Bloomington, IN- Looks like I'm heading out for a last fling this weekend in unfamiliar territory: the Northern Plains. After working a hard month on the book (about 100 pages of first draft stuff on paper), I'm taking a fourth of July weekend to chase around the untested fields of SW Iowa tomorrow, Western Nebraska on Saturday, and perhaps Southeastern South Dakota on Sunday. A zonal pattern of strong midlevel winds should establish over a very unstable airmass at the surface, and with the proper disturbances, wind shear, and boundaries, tornadoes are possible all three days, particularly Sunday, I think, when dynamics are stronger.
Even tomorrow isn't out the question, and I'll pace myself to arrive in SW Iowa in time to take a look at the setup, hopefully arriving in the area before 4:00 PM. I'm curious about the area outlined by Adair to Pottawattamie to Fremont to Taylor Counties in the SW quad of the state. Much depends on surface features and if any backed flow enhance SRH for isolated storms that may appear. Tomorrow is the least promising of the three days.
I'm printing out maps of these states with counties in bold. The Census Bureau website comes in handy for that.