RF17: 15-6-2002 17:19 - 21:26


P3 Flight Log:

The forecast for June 15 was for an upper-level jet streak to move over southeastern Colorado and southwestern Kansas. This was more like an early springtime situation rather than mid-June. The SPC forecasters predicted cyclogenesis somewhere in southeastern Colorado which would bring strong westerly winds over the Texas and Oklahoma Panhandles as the center of the low began to move eastward. This westerly wind was forecast to set-up a dryline that would be north-south and intersect the low pressure and possible east-west front at a triple point. A moderate risk of severe storms by the SPC and the forecaster claimed that the helicity was among the highest values he has ever seen. After extensive discussion with the ground armada, it was decided to target Dumas, Texas (IP 36 x 102 degrees). Takeoff for the P-3 was set for 11:00 am CDT (actually takeoff was 10:55 am). The King Air and Falcon (the latter was only participating in its second mission in conjunction with CI) were to takeoff at 12:00 and the LearJet was to depart at 12:30 with the potential to perform 3 dropsonde legs. No true boundary was detected as we arrived in the target area. Discussions with the SPC and the Ops Center suggested that the target should be moved to 101.5 degrees where weak convergence was being detected. We decided to setup three long east-west legs between longitudes 102.5 and 99.5 at latitudes 36, 36.5 and 37 degrees. Soon after setting up the legs, we were informed that the FC was setting up their IOR in Guymon, OK. At approximately the same time, we were informed that the LearJet was set to drop sondes between 102.5 and 100.5 at a latitude of 36.5 degrees. This was chosen since the Falcon had already set up their east-west legs at that latitude and longitudes. I decided that it would be best to shift the whole pattern to 37 degrees latitude owing to the location of the IOR. There was some difficulty setting up this change owing to a combination of miscommunication and malfunctioning of Hanne?s headset which did not allow her to listen in on the pilot-to-pilot conversation. The coordination between the Lear and the Falcon occurred at approximately 2:00. Soon after we learned that while the Falcon understood the change but the LearJet did not. The latter shifted their IP to 37 degrees but left their EP at 36.5 degrees. This was unfortunate and the LearJet did attempt to correct this at the end of their leg. We broke off into an along-the-fineline pattern about the same time. This was one of the more difficult patterns I have flown during the project. I discovered later that there were at least two fine lines which merged in our area. In addition, they each had different characteristics. One was associated with a windshift but no moisture discontinuity while the other was associated with a moisture discontinuity but no apparent windshift. Adding to the problem was the fact that the realtime CAPPIs would not work so I was left with navigating the P-3 with in situ data and the RHI scans from ELDORA. Several of the legs were flown well while others were not. We continued to execute these patterns until I was told that ELDORA was reaching the 100 degree mark. Reluctantly, I told the pilots to gain altitude and ELDORA and LEANDRE were shut down so the electronics would cool off. After a short period, we decided to descend over S-Pol. Unknown to me, the pilots intended to fly over the S-Pol site at about 300?! We attempted to sample a fineline that led into an intense supercell which spawned a tornado. Unfortunately, second-trip echoes were prevalent and we decided it was prudent to terminate the science part of the mission. We flew a radar calibration leg for ELDORA and attempted to execute the Don Lenschow pattern. However, the paper that contained the latter pattern (which had been provided to the pilots) had either been misplaced or lost. The NCAR personnel aboard the plane did not have an extra copy so Jeff Keeler and Bill Erwin attempted to reconstruct the pattern from memory. Hopefully, the reconstructed pattern was close to what we needed to calibrate the instruments. We headed back to Will Rogers Airport and landed around 6:00 pm.

Flight Track:

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