Tuesday, 6 June
T-28 Flight 752
Project Flight 7
Take Off ~ 23:45 GMT
Return to Base: 01:15 GMT
Pilot: Charles Summers
The mission investigated a two-cell complex ~50 mi west northwest of CHILL. There were 5 passes along a southwest-northeast axis through the two cells near 6 km MSL where the temperature averaged -10 °C. Up to ½ inch of ice collected on the wings. Updrafts were < 5 m s-1 and cloud liquid water concentrations peaked at a few tenths of g m-3. The pilot noted frequent lightning, and a lightning event is visible in the flight video at 00:50:30 . The southern cell of the storm made no CG’s detected by the NLDN, although the CG flash rate in the northern cell peaked at 6-7 min-1 for several minutes. LMA observations suggest that the electrical structure was inverted, with negative regions near cloud top overlying positive regions below.
The average penetration altitude was 6 km. The Ez electric field component switched sign often; some of these are easily identified as being caused by lightning flashes near the airplane. The pilot reported that lightning flashes were so frequent (every few seconds) that he got tired of reporting them. The Ez component was as strong as 30 kV/m.
The HVPS recorded many particles that carried charge. In some regions, both positively and negatively charged particles were measured, but in some regions, negatively charged particles outnumbered the positive ones. On one occasion, just after 24:12:00 UTC, the particles carried a large magnitude of charge, but the electric field was relatively weaker than the in an adjacent region, just before this.
There was good coordination with the mobile mesonet. There was no electrical ballooning effort for this storm. No ice phase precipitation was noted at the ground. Some strong outflows were observed as cells collapsed, accompanied by temperature rises of 2 to 3 °C.
HVPS image recording failed after 00:36:17. Large aggregates were observed in places by the HVPS, 2D-C and hail spectrometer. Except for the HVPS failure, data is of generally good quality.