Day 7 was a similar chase call from previous day -- the surface featured a stalled front across northern Oklahoma with pendant dryline draped southwest-to-northeast across western Oklahoma into northwest Texas. We favored west (as much as we could) to avoid the terrain and road network issues found in central and eastern Oklahoma. After a brief tour of the National Weather Center at OU courtesy of Paul Downes, we left Norman and headed southwest toward a region of aggressive cumulus development to our west along I-40 a little after noon. We intentionally went southwest to Chickasha then to Anadarko, anticipating that if storms managed to break the healthy cap (per 18Z OUN sounding) early we’d want to be far enough south to avoid convective mess due to storm splits. The cap broke roughly mid-to-late afternoon, with several cells going up around Bridgeport, OK. These storms ended up becoming the dominant force for the remainder of the day in our immediate area. At any given point there seemed to be 3-5 distinct updrafts, but very close together with lots of interaction. The storms that did become supercelluar were very much high precipitation. The lead supercell that initiated near Bridgeport marched eastward, munching on I-40 while we sat just north of sr-152 and just south of the the Canadian River. Frustrations with limited visibility due to trees lining the farm roads, not being able to have quick access across the Canadian, and increasing chaser convergence forced us to try to get north of the Canadian on 81 and sit just east of Union City. With now limited road options south we had to make the call to either wiggle back south on 81 or attempt to get east, just to stay with the storm and have some sort of view, with sr-4 (south) being our route out. At this point we had never been closer than 4-5 miles south of the main circulation of the lead storm. We knew there was a tornado well within the rain curtains that was violent via radio reports and we had fully intended to keep our distance. The circulation was apparent within the HP as it moved due north of us as we sat east of Union City. The wedge was very difficult to make out, but it was clear a broad and violent circulation was approximately 4-6 miles to the north. This was the approximate time that chasers in that area were overtaken. We eventually busted east on sr-152, paralleling the tornado. As we neared sr-4, the residents of Mustang and several surrounding towns began fleeing their homes in their cars, trying to rush south to safety, which resulted in a crippling traffic jam (nearly a dead stop). Even on side roads, locals were frantically trying to get as far south as they could by taking up oncoming traffic lanes. Around this time another storm further west was developing a significant velocity couplet. It was clear that our slow crawl south on a side road just west of the parking lot that was sr-4 was quickly becoming a safety issue. From this point on, all actions/decisions made by us and the drivers were entirely based on the safety of our students. We made a critical choice to turn around and slide north, threading the needle of the mesos now (roughly) 7 or so miles east and west of us -- we were able to gather enough information from the data we had to make the call to go north. Thankfully we were not stopped by oncoming traffic in the wrong lane or hail, and the winds were not terrible at the time in the forward flank downdraft, but we did come across some damage (e.g. downed trees and powerlines). What became of critical concern were flooded roadways. The slow moving, training(ish) nature of these storms lead to flash flooding. Eventually once we got reasonably far enough north, we stopped the vans near an awning of a local bank in Yukon. We had made contact with the CoD weather lab at this point and managed to get just enough of a data connection to get a velocity image to calm nerves regarding the tornado threat. Hail and flooding were really the only thing to manage beyond this point, so we held tight at the bank for about ten minutes. Since we were now on the northern fringe of the convective complex, we made the decision to call it a chase soon thereafter and ferry (as best we could due to road closures) to Stillwater, where we overnighted at a remarkably nice Residence Inn. [original text by Evan Anderson; modified by Walker]
Our view of the El Reno supercell as it transitions to HP mode -- shot looking northwest from Union City.
Looking north, with violent wedge ongoing approximately 4-6 miles north. Due to the violent motion visible in the RFD, we decided to parallel the storm east and not head closer to the circulation.
Trip 3 participant Laura Hedien's zoomed in picture of the cloud filaments along the edge of the wedge.
Wide-angle timelapse perspective of the deadly supercell.
After chasing for a solid seven days -- as well as hearing of the tragic loss of life the night before due to the tornadoes and flooding -- we decided not to chase on day 9 (Saturday) and, instead, head to Omaha to take in an Omaha Storm Chasers minor league ball game. The park was beautiful, the weather was not too shabby, and, of course, the company was great. And, the Storm Chasers won! We had a wonderful time and it was a fitting end to a rather hectic trip. We all learned a lot from this trip, and will be reflecting on the storms, the events, and relationships made for years to come. Thank you Trip 3 students, drivers Leon and Joe, and assistant Evan for a trip that none of us will soon forget.
COD Trip 3 2013 at Carhenge near Alliance, NE.
No comments:
Post a Comment