JD: 00-182 DoW: THU/FRI UTC Date: 30JUNE2000

SUMMARY: Sprites Above Long-Lived MCS in Kansas; Gravity Waves

TLE PREDICTION: 0.4 [0.8 x 0.50]

RESULTS: 26+ sprites from target storm; gravity waves imaged

LESSONS: Classic TLEs over trailing stratiform

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

Guests: Fernanda de Sao Sabas; Victor Pasko

STEPS STATUS: STEPS up. Great Data

YRFS OPERATION LOGS: Full Operations. Unusual system formed before noon in SD and slowly migrated south through NE and into KS. It generally stayed east of LMA (where other cells were present). Had very high positive rates at times (70% at sunset). After sunset system had well defined southward moving bow echo and classic trailing stratiform and secondary reflectivity max. Sprites present right after dark. VLF sounded very promising-much spider activity? Beyond LMA most of surveillance time, but trailing positives may have been within coverage area. Sprite rates slowly went down as flash rate dropped and percent positive waned after 0440Z. A final flurry of sprites occurred around 0530Z as the storm continued to weaken. Utah State and GEN III saw gravity waves upwelling from storm. Stanford telescope on. Have a few tele Xybion shots. Took digital samples

Lyons has pictures of convection from B757 over NE around 0030Z.

STEPS OPERATIONS: Well this was the event we have all been hoping for, and we got it! A tremendous supercell storm was in the east Doppler lobe for over two hours. Observations included excellent Doppler coverage by CHILL and S-Pol (great coordination on scans), four EFM launches, T-28 penetrations, excellent coverage by the mobile mesonet (with observations of a tornado) and supporting soundings measurements. LMA reported flash rates of 1 per second at times. One particular highlight was the fact that the storm became a right mover near Wheeler around 2330 UTC. This behavior was accompanied by the onset of positive CG's and the occurrence of a tornado. The first tornado observation was noted around 2330 UTC, AZ/range of 57 degrees, 75 km from CHILL (reported by NSSL5). Prior to this time the storm produced only one positive CG, and was primarily an intracloud lightning producer. The storm was reported as having an inverted polarity structure prior to the turning and onset of positive CG's.

Near 2350 UTC, the storm featured a well-identified BWER with tops to 15 km. Ldr values as large as -15 db in the hail shaft. Reflectivity of 60 dBZ were maintained to 10 km AGL for a good deal of the time the storm was in the east lobe. First EFM was launched near Wheeler into the mesocyclone. NSSL5 was then directed south and east and ended up setting up for further launches near Brewster KS. Second EFM launch was 3 mi. west of Brewster, again into mesocyclone. Third EFM was also into mesocyclone near 0045 UTC at Edson, KS. The fourth EFM was sent up into a strong core that was just north of I-70, with was north of the main core that the previous EFM's had been launched into. This storm was targeted since it was producing positive CG's and had a mesocyclone. If NNSL5 would have stuck with the southern storm that they had been working, they would have been directly in the path of the mesocyclone associated with the northern storm. This location was undesirable for obvious reasons, and hence the northern storm was selected. The Hailstone van set up near Brewster too, and got a great core penetration near 0030 UTC 30 June. There were numerous reports of hail exceeding golf ball size in this area. The manual hail catcher was used, but the software on the SDSMT hail box was not operative after several reboots.

T-28 penetrations were conducted between roughly 2240 and 2340 UTC, 29 June. A total of 6 passes were made. Pass 4 and 6 were most interesting, with a peak updraft of 33 m/s on one of these passes. Heavy rain, moderate hail and continuous lightning were observed on these passes. Unfortunately the engine on the T-28 seized just before landing and the aircraft is down for the rest of STEPS. The aircraft was able to land at the Goodland airport, thanks to the tremendous skill of pilot Tom Root. We are all thankful that Tom made it back to Goodland safely. The T-28 provided 14 flights for STEPS and performed very well.

Utah sets up Cooled 12 bit, 512x512, bare CCD imager, filtered for OH (710 nm). Also a narrow FOV GEN III Xybion.

KEY RESULTS : Sprites form in expected area, but stop rather early while there was still quite a large stratiform region and fair lighting rates. What criteria was "met’ to turn off the sprites

Total TLEs from Yucca Ridge This Campaign: 600

FMA

Red Xybion (A)-Patrol: 2 tapes

Sony TRV900 3CCD: 2 tapes w/ sprites and gravity waves

GEN III unit; 2 tapes to S-VHS

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

Pulnix CCD: shoot various TL scenes

Photodiode: available

Winckler PMT: used

GPS: OK

WWV Source: OK

VLF Inspire: Used

ELF N-S: not available

ELF E-W: not available

NLDN Live: OK

NLDN Paper: 8 maps

NLDN Archive: 1 saves

MRC Data Acquisition: available

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

GOES Archive: OK

RUC2 Archive: OK

STANFORD/STAR LAB:

Telescope OK

LLTV avail

ELF/VLF avail

UTAH STATE UNIVERSITY:

Xybion GEN III (6 deg FOV)

Wh or blue

CCD, Med Field OH imager

Grav waves/sprites

MIT ELF: operational

FUELLEKRUG ELF: operational

ISRAELI ELF: nominal