Thursday, May 30, 2013

5/27/2013 - COD Trip 3 Day 4

[Text courtesy of Evan Anderson] Hope was high for north central Kansas for at least a day or two in advance, anticipating a highly primed environment ahead of a low in western Kansas. Very steep lapse rates overtopping a very warm and moist boundary layer environment just north and east of the low with strongly backed surface winds, leading to a veered vertical wind profile with gobs of shear. To top it off we expected a *real* shortwave to finally eject from the desert Southwest. Fly in the ointment, or rather… the unforeseen element (at least from model land) was the southward propagating outflow boundary (OFB) that was continually reinforced from remnant MCSs that had developed across Nebraska and Missouri the previous night and pushed southeastward. The OFB pushed pretty well south in eastern KS, but stalled much faster near the low and still allowed for a triple point type setup to establish just a hair west of what we might have earlier thought, in the Russel to Osborne to Smith Center area. Departed from Kearny, heading south, had lunch at Jiffy Burger in Smith Center, continued south to Osborne and decided to allow things to develop. After several hours in Osborne convection first ignited along the front range in CO, then began to develop in southern Nebraska. Roughly about the same time convection began to develop from PHG to EAR, we noticed some mushy towers with respective echoes on radar southwest of us near Russell/Hays area. While RSL/HYS area seemed to be more in the area we had initially been expecting, thorough interrogation of the current setup led us to believe that a retreat north to convection headed into Smith County was warranted. Better backed winds that were strong and were transporting very juicy low level air, less risk of dry air entrainment, and the pure fact that the storm seemed to be organizing and the towers we saw to our southwest were mushy.

As we intercepted the southern-most storm to our north, we also collided with the hordes of other chasers that had converged on the same location. This led to frustrations in all attempts to stop to view the storm and then reposition because of the train of chasers on 36 east! We resorted to staying a touch closer to the storm on farm roads just north of 36, and while we saw numerous scud bombs under the cloud base, several cuts from descending RFDs, we never conclusively saw anything more that possibly 1 or 2 gustnadoes very early on near our arrival at the storm [these were later confirmed as bird fart tornadoes of 10 and 15 yards wide ... see time lapse for circulations]. As we paralleled the storm, it did manage to develop rapid rotation deeply shrouded in its precipitation core which we were unable to see; however, the storm did appear to intensify at this time. It’s more than just likely that there was a tornado in there… we simply could not see it and it was entirely too dangerous to make any attempt to do so. Shortly after this point, Van 2 began to have potentially crippling electrical problems that appeared to be the result of a failing alternator. We broke off the chase at that point and proceeded to the hotel with only a couple stops for gas and to view under-lit mammatus.

The very definition of a bird fart tornado [see EF0s] -- a dust swirl under a NWS-confirmed tornado. Hmmm ... I guess the definition of violent is different for some folks. 




Tuesday, May 28, 2013

5/26/2013 - COD Trip 3 Day 3

We spent most of the afternoon enjoying the "wildlife" at a large park on the north side of North Platte before things finally started to pop to our north. As we began to hedge north, the initial convection weakened. We then caught visibility of new tower development to the east of North Platte. After negotiating the poor road network in the Sand Hills, we finally latched onto a supercell near Ansley, NE. The storm was another structure fest. It even tried for about 10 minutes near sunset to produce. Alas, no tornado. But, who needs tornadoes when you have such magnificent structure? We followed it east for a bit, then let it go after sunset and began to head back to Kearney. We stopped for one last look as a lightning filled sky illuminated a beautiful mammatus display. Pics and a time lapse follow.











Monday, May 27, 2013

5/25/2013 - COD Trip 3 Day 2

We targeted the Chadron, NE area on this slight risk day. After lunch at Wreckers and waiting in the town park for an hour or so, we bailed north to a storm just north of Rapid City that was anchored to the Black Hills. We arrived just in time, as the storm detached from the mountain and, subsequently, put on a structure fest. We followed the storm from just north of Rapid City to Wasta, SD.  The storm revealed amazing mid-level rotation, transitioning slowly from a classic supercell in the afternoon to an shriveling LP at sunset. After this amazing atmospheric treat, we ferried to Valentine where we overnighted at a mom and pop motel.









Sunday, May 26, 2013

5/24/2013 - COD Trip 3 Day 1

We left Glen Ellyn, IL at 6 am for a slight risk opportunity in northeast Colorado. After a long day of driving, we arrived in time for convective initiation at our target of Holyoke, CO. Storms had transient supercell structures, but, overall, they left a lot to be desired. After watching the last of the storms mature and move off into a poor road network, we headed north to Ogallala, NE where we overnighted. A pic and lapse follow.




5/16-18/2013 - A few chase days in Kansas/Nebraska

I was able to slip away for a few days of chasing before I had to travel to DC for work.  I chased May 16, May 17, and May 18. The 16th featured a marginal setup, which ended up producing outflow dominant storms with little or no organization in southwest Nebraska. The 17th featured a couple of transient supercell structures in the Sand Hills of Nebraska. The 18th was the more significant risk; however, I seemed to  intercept every storm except the tornado-producing one near Rozel, KS.  I did photograph initial convection north of Wakeeney, then a supercell near Hays that suffered from cold RFD surges, and finally an intercept of an east-to-west sky full of amazing convection near Hoisington.  The latter was a real treat, producing numerous funnels and a wicked skyscape. Below are some pics, as well as lapses corresponding to the days.

May 16


May 17


 






May 18


Note horseshoe vortex in right-center side.