June 8, 1994

Vortex Aircraft Mission #9

Flight ID:

940608I

Flight Track:


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Flight Crew:

Chief Scientist: Watson/Ziegler         Flight Director:  Damiano
Doppler Radar:   Shepherd/Atkins        Pilots:           Ticknor/Kennedy
Cloud Physics:   Pradas                 Data Technician:  Jacobs
Observer:        Bluestein              Systems Engineer: Lynch
Observer:        Jones (NWS)
Observer:        Hutchinsen


Takeoff Time: 1932 UTC                  Landing Time: 0228 UTC
Official Mission Duration: 7.2 hrs
Number of Data Tapes Used:  Radar: 2    Cloud Physics: 0        Video: 3

Data Systems Log

Radar Data System Log   Time On(UTC)    Time Off(UTC)   Comments
Tape #1                 2116                            Start LF
                        2131                            Start TA
                                        2328            Radar down
Tape #2                 2333                            Start REC again
                                        0132            Stop Record


Cloud Physics Log       Time On(UTC)    Time Off(UTC)   Comments
                                                        No clouds - No data

Summary:

The preflight plan was to document the mesolow, dryline, and outflow boundary in west central Oklahoma with high dewpoints extending into the Enid,OK area. To examine the cap, a descent sounding would be done in the vicinity of Seiling, OK. We would then perform preconvective patterns and hope for convection.

We departed Will Rogers at 1932 UTC. The FC had already departed about the day when we made initial contact. He suggested we fly at 10,000' northwest to the Oklahoma panhandle to check the extent of warm temperatures at 700 mb. On our track, temperatures decreased slightly from 15 to 13 C. At Englewood, KS (extreme southern Kansas), we performed a descent sounding to 500' AGL which showed a severe cap (6 C inversion) at 830 mb. We then contacted the FC (2027 UTC), who had already cancelled ground operations and, at that time, released us to seek out severe convection elsewhere.

Based upon the FC and EFF's suggestions, we headed northbound to convective development already occurring in western Nebraska. NOAA 43 arrived in the vicinity of the convection one hour and 15 minutes later (2142 UTC). We would work a linear system near Sidney, NE for approximately an hour before deciding it would not tornado. Several cells looked good in the line containing bounded weak echo regions. Howie Bluestein reported a "gustnado" on the outflow boundary at 2215 UTC.

At 2306 UTC, we headed southbound for an isolated cell about 50 nm southwest of the line we were working. At 2306 UTC, we started our first pass westbound. At 2321 UTC, we observed a funnel cloud (tornado) extending out of a small narrow wall cloud. Upon reversing track, the tornado had dissapated and the wall cloud had become wrapped in rain. We executed some 14 passes on the supercell as it evolved, first, by weakening somewhat, then, by the time we had to depart, the cloud had developed a nice horseshoe-shape appearance. Tom Shepherd, on radar, did at least 4 passes using all fores and all afts technique. On the last few passes, we observed striations at midlevels of the cloud indicative of a rotating mesocyclone.

Irv Watson

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