JD: 00-176 DoW: FRI/SAT UTC Date: 24JUNE2000

SUMMARY: Sprites Over and Near The LMA

TLE PREDICTION: 0.32 [0.8 x 0.40]

RESULTS: 132+ sprites; some over or near LMA

LESSONS: Smaller MCS Makes More Sprites; Few from large MCS???

PERSONNEL: Lyons, Nelson, Fossum, Nordem, Gerken,

STEPS STATUS: STEPS operates. Works until 0000Z.

YRFS OPERATION LOGS: Full operations. Cells formed in eastern CO (some dry microbursts along Front Range) and moved eastward, passing the LMA in the evening. The Kansas MCS was large, and had periods of colder than –75C cloud tops. It had a well-developed trailing stratiform. It was caught making sprites just after dark as it was exiting the LMA. Then the rate dropped off, though it did make occasional rather big sprites. Spengler’s light and low clouds made viewing KS storm difficult, so we switched to the much smaller though intense (mesos, TVS) system 350-400 km out in NE. Some radar coverage was missing so it is possible that it was bigger than shown in the regional mosaics. But the cloud top shield (which was much larger than the echo) was notably warmer than the KS system for much of the time. Once the NE system started marking sprites it made many, some at a very rapid rate for a while. But the sprites tended to be rather small and dim, often horizontal "combs" Several elves and halos were seen. Four s-storm watches issued after dark. Ran red patrol, zoom and tele, along with GEN III (and S-VHS dub). Did not mount PD (storms too far). Used Winckler and VLF. New switch install, though still had some trouble catching all triggers. Less VLF interference than night before. Took many digital samples. Stanford got some good shots with telescope of both storms. Still problems with cross talk in the digital samples.

The debris clouds evaporated very rapidly after sunset. The sky was "bright" however, possibly due to OH glow or dim, diffuse aurora. Stars not very crisp, but overall visibility was quite good. Moon became problem by 0700Z, and low clouds blocked view of distant storm's operations shut down.

STEPS OPERATIONS: STEPS goes for early ops. Operations centered on a multicellular line of marginally severe storms that developed from southwest of CHILL northeastward to near Goodland. Heavy rain with occasional pea-to-dime size hail and surface winds up to 30 ms-1 were reported with some of these cells. Radar operations concentrated coordinated scans on cells developing in the triple Doppler triangle and then within the eastern dual-Doppler lobe. The cells did not produce a lot of CGs, but were predominantly positive in polarity. The T28 was called up at 4:00 pm, and did transects of the convective cluster between 4:30 and 5:30 pm. One mobile mesonet and the hailstone van sampled the cells while the T28 was on station. No mobile electric balloons were launched, as it was decided that the

convection was too disorganized. Operations shut down at 6:00 pm. Mark ran interferometer during the day and partially into the night. Still problems with disk overheating

KEY RESULTS : Best night so far. Many sprites observed in or near the LMA coverage. BUT very strange…..the very large MCS with trailing stratiform produced a few big sprites, whereas the very small (but severe) MCS in Nebraska made for numerous but smaller sprites. WHY? The NE storm may have the best chance for being detected by the LMA.

Total TLEs from Yucca Ridge This Campaign: 532

FMA

Red Xybion (A)-Patrol: 2 tapes

Sony TRV900 3CCD: shot TL scenes of clouds;

GEN III unit; 4 DV tapes w/ sprites; 2 S-VHS w/ GPS

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

Pulnix CCD: shoot various TL scenes

Photodiode: not used

Winckler PMT: sampled

GPS: OK

WWV Source: OK

VLF Inspire: sampled

ELF N-S: not available

ELF E-W: not available

NLDN Live: OK

NLDN Paper: 13 maps

NLDN Archive: 4 saves

MRC Data Acquisition: OK- many samples; still iffy- trigger

FMA Data Acquisition: not available

Thunder Mic: available

LANL Tracker: OK

Red Xybion (B)-Zoom; 2 tapes (on tracker)

Red Xybion (C)-Tele: 2 tapes-on tracker

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 OK-good data

LLTV OK

ELF/VLF OK

UTAH STATE UNIVERSITY: not present

MIT ELF: problems with vertical antenna?

FUELLEKRUG ELF: operational

ISRAELI ELF: nominal