JD: 00-186 DoW: MON/TUE UTC Date: 04JULY2000

SUMMARY: Sprites from Two Large MCS in KS and NE, Gravity Waves

TLE PREDICTION: 0.72 (0.8 x 0.9)

RESULTS: 70+

LESSONS: Why Relatively Few Sprites from Such Large Cold Systems?

PERSONNEL: Lyons, Nelson, Fossum, Nordem, Gerken, Taylor, Gardner, Rina,

Fernanda

STEPS STATUS: STEPS scrambles back to operations. Limited operations.

YRFS OPERATION LOGS: Full Operations. Storms formed as predicted in sw Kansas and central Nebraska. Skies so clear at sunset could easily see tops at 450+ km range. Very high surface dewpoints and huge CAPES allowed both multicellular convective systems to spawn considerable severe weather (hail, TVS, mesos, tops to 650). The northern, stronger system built southwest and gradually merged with the southern system. The tops were very cold, with large areas under –75C. However, the sprites were relatively muted for large systems. The NE system sprited for a while, with nothing from KS. Then KS took over, and then off and on sprites after the merger. The fact that the percent positives were consistently under 10% and that the convective regions were quite a large percent of the total storm may be a factor. Some were visible to the naked eye however. Excellent gravity wave images were obtained. A number of Stanford telescope views obtained. Tried the GEN III with the 500 mm lens. USU obtained some GEN III blue filtered sprite shots (0552.05). Low clouds redeveloped causing loss of viewing so shut down was at 0815.

Smoke from Craig fire seen layered to northwest, but did not appear to affect storms.

STEPS OPERATIONS: STEPS down at 2356Z. A north-south oriented squall line storm developed west of a line from Limon to Akron CO. The line advected slowly eastward, with short-lived cells within the line advecting northeastward. There were two complexes east of Goodland, one southeast of Colby and the other in south central Nebraska northeast of McCook. Both of these complexes as well as the western squall line produced outflows that were expected to collide somewhere within the triple-Doppler triangle. Around 2050Z, the ballooning unit came west to intercept the western squall-line, but it didn't hold together once the outflow had outrun the line itself. The line and all other echoes were covered with multi-elevation angle surveillance scans with RHIs every 5-10 deg along the line.

Operations were called down at 2356 Z.

KEY RESULTS : Some sprites may have been on fringe of LMA

Total TLEs from Yucca Ridge This Campaign: 900+

FMA

Red Xybion (A)-Patrol: 3 tapes

Sony TRV900 3CCD: time lapse of late storm

GEN III unit; 5 DVs of srpites (500 mm at first, then reg; not all on S-VHS)

JVC KY-19: shoot daytime TL/STEPS Cam (to ESE);

Pulnix CCD: shoot various TL scenes

Photodiode: not used

Winckler PMT: available-not used – too close to horizon

GPS: OK

WWV Source: OK

VLF Inspire: many samples

ELF N-S: not available

ELF E-W: not available

NLDN Live: OK

NLDN Paper: 14 maps

NLDN Archive: 3 saves

MRC Data Acquisition: many samples

FMA Data Acquisition: not available

Thunder Mic: available

LANL Tracker: OK

Red Xybion (B)-Zoom; 3 tapes (on tracker)

Red Xybion (C)-Tele: 3 tapes-on tracker (used in patrol mode; no tele)

Blue Xybion(D)-zoom: 0 tapes - problems with focus

Mountain Cam: nominal

STEPS Cam: nominal

Shure Mic: OK

NEXRAD Archive: Revised EDIS, many manual saves

GOES Archive: OK

RUC2 Archive: OK

STANFORD/STAR LAB:

Telescope got shots

LLTV ran

ELF/VLF/PMT ran

UTAH STATE UNIVERSITY:

Xybion GEN III (6 deg FOV) excellent gravity wave images

White or blue

CCD, Medium FOVOH imager white and blue filtered GEN III sprites

Gravity waves/sprites

MIT ELF: operational

FUELLEKRUG ELF: operational

ISRAELI ELF: nominal