6/15/2009 - Assumption, NE Tornado

Monday, June 15th, was one of the most rewarding chases of my career. I began the day in Goodland, heading east toward Oakley, KS in the early afternoon. I had two choices -- go south toward the Dodge City region to intercept supercells (high-based?) that would fire early (safe bet) or keep my eye to the north where convergence was focused, shear was maximized, but a strong cap could possibly leave one with nothing more than a sunburn. I decided on the second option for a few reasons: 1) the north option put me a bit closer to home (my wife was beginning to wonder if I existed; I needed to be home Tuesday), 2) the massive chaser convergence in southwest Kansas (per spotter network and all the talk on the boards) was persuading me to stay away from there, and 3) the boundary along the KS-NE border just had that "come get me" appearance on satellite. So, I meandered over to Wakeeney and then north to Norton. At this point, I gassed up and kept an eye on a few cus nearby, none of which were screaming "I'm gonna do it!". Despite a fairly good connection, my data was rather slow to arrive on the laptop. In a way, this was a blessing -- I didn't have to stare at the storms on radar down in southern Kansas that were surely doing something magical. Instead, I just looked in awe at the backsheared anvils to my south and pressed northward hoping that something -- anything! -- would go up in my target area. As I slid east toward Phillipsburg, I noticed some nice towering cumulus to my southeast, and eventually to my east. These towering cus appeared to go up in full sunshine and then immediately die once the anvils from the central and southern Kansas storms spread over top. I gulped and thought this was going to kill any convective initiation up in my area. Ugh. Still, I pressed on eastward. Near Anthol, KS, I was able to download a few images from the Blue Hill radar on GRLevel3, which, when animated, told me that convergence was rather focused just west of the Hastings area. I then jumped north on a state route toward the Minden, NE area. Near the Nebraska border I could begin to view some towering cu in a mass of clouds to my north. I then noticed a "blip" on the radar. Okay! Heck, just a few minutes prior, I thought I was going to bust hard (it was getting quite late at this point!).

I drove up on the developing supercell near Norman, NE. Basically the next hour was just supercell magic. I slid east on SR-74, making frequent stops to bathe in supercell delight. Just south of Assumption, I pulled over and watched one of the more dramatic occlusion processes I've ever witnessed. When my storm chasing brain told me to go east (to jump in front of the new meso off to my immediate east), I stayed -- not sure why I did. Perhaps it was to talk to the locals/farmers who had joined me in viewing this rather amazing supercell as it neared their own homes just to the north. The decision to stay was rather fortuitous -- as the occlusion took place in front my eyes about 1-3 miles up the dirt road from where I sat. I was a bit shocked at how "late" the meso tornado'd in the occlusion life cycle. The meso funneled a few times and then laid down a cone/barrel-type tornado, which then morphed into one of those stretched-occluded-type (not a rope, per se) tornadoes. After the tornado, I played catch up the remainder of the short evening. I finally got ahead of the storm near Lawrence, NE, but visibility was starting to wane in the evening light. I enjoyed a nighttime lightning display as the shelf cloud overtook me near the town of Hebron, NE. I then threaded the needle between storms and drove to York, where I overnighted. Overall, patience paid off today. Thanks to Matt Powers for nowcasting (and moral!) support.

Also, a special note to the locals that I spoke with that evening -- thanks for the emails and the pics you've sent. I'm thankful that the tornado did only minor damage and largely moved over open farmland. All the best to you all.

Clear slot wraps in.

Second funnel ... first one (and possible tornado) seconds earlier blocked by the only tree in my view -- chainsaw anyone?

Tornado!

This pic was sent to my be Helen Parr -- I met her brother-in-law that evening just south of the tornado. Her view is about a mile or so south of where I was. Thanks for the pic Helen!

Wide-angle view -- showing the jaw dropping clear slot and occlusion process.

Base reflectivity illustrating the interesting occlusion occurring. Note the hook, with appendage, to the south of the forward flank downdraft -- yet this is not where the tornado occurred. See the velocity product below for where the strong rotation was.

Storm-relative velocity product at the time of the tornado. I've made animated gifs of the bref and srv, which show the pretty cool meso spin off.

Time-lapse of the day's action. Includes views from two cams (one regular, the other HD); thus the repetition in some clips. Also, I had to move to get out of the way of emergency vehicles as they approached from behind at one point. Thus the movement and unstraight horizon lines at times. Sorry. A higher resolution video is available for download here .. please right click>download; don't stream from the server. Thanks!

Geography of my Trip 3, with overnight stays in red. This successful chase concluded my formal trips into the Plains for this season. For the remainder of the warm season, I'll chase local or in nearby states (e.g., Iowa).