10 June 2003 – Flight 807

Research Flight from OUN

Pilot: Tom Root

T.O. 22:37 UT

T.D. ~23:24 UT

A storm complex starts to fire up to NW at 50 nmi at 20:00 UT. Initially there is little movement of this complex. But as it develops, and an upper-level shortwave moves across, it starts to move towards Norman just about at the time we launch, forming into a classic squall-line.

Take-off at 22:37 was followed by a climb to the W where the storms were near the 50 nmi range marker. Peak reflectivities exceed 65 dBZ at this time. An NO test was done in the clear at 22:56 using a calibration mixture that had been put into its Tedlar bag the previous day. The first cloud pass to the west at an altitude of 17 kft started at 22:59 UT. Tom did not like the way the engine was running and did a 180^o turn to the left to exit the cloud. He could not get the engine into high blower. We decide to re-enter cloud at 17 kft without being in high blower, but at 23:09 the data system quit. A 180^o turn to the right brought him back out and was followed by descent and return-to-base. It turns out that the data system came back on during descent. The data indicate passage through several precip-free cells with cloud liquid water peaks in the 2- 3 g m^-3 range as the aircraft flew homeward through the developing cells out ahead of the advancing squall line.

Outflow from the storm the aircraft was working to the W and NW triggered some new development right over Norman, and very heavy rains with flash flooding developed through the evening.

There were many empty buffers on the 2-DC. Hail images were OK where there was hail.