New Mexico Tech Interferometer/Sferic System
Notes for August, 2000

Universal Date/Time
JDay Date Time Comments
216 03-Aug 04:25 Line of storms to North. Closest cell was near Wray at 4:03 UT (time of last NEXRAD image).
4:39:20 Removed metallic push rod which was leaning against the vertical baseline between the short baseline antennas. The rod was in place the past few (dry) days in order to help remove the warped nature of the lower pole segment.
5:20:40 Gust front hit
5:24:30 Strong gusts!
5:35:55 -CG seen to ~East. Many strokes and a CC.
5:39:58 Discharge with horizontal propagation & high elevation channels. Delta-E is offscale.
5:41:00 Rain falling
5:42:39 Nice negative delta-E
5:43:30 Heavy downpour
5:45:23 Nice negative delta-E
6:34 Cells to ~N to NW are getting closer. The cells formed behind the line.
6:41:05 -delta-E offscale from -CG to Nw
6:44:14 Close discharge with multiple stepped leaders to ground
6:45 -CGs every ~15 secs are striking within several kilometers or less
6:47:40 Close CG! <1 km away
6:50:08 Close discharge at ~2 km range. To ~W based on sound?
6:50:30 Discharge at 3 km to NW
6:51:58 Close discharge at ~1 km
6:52:46 CG at 4 secs to thunder (slightly greater than 1 km range)
6:53:10 CG at ~2 km
6:54:52 CG to NW at ~3-4 km
6:58:03 CG at ~1 km
6:59:14 "Close" CG at ~2 km affected power
7:00 Storm moving off to SSE
~7:45 Checked all phase outputs. OK.
7:54:41 Power tripped (glitch)
7:58:35 -delta-E offscale at about -2.5 V
8:00:40 ~Long duration -CG flash
8:04:30 Rain falling
8:05:05 Power glitch
8:38 Lightning activity appears to have died
218 05-Aug >2 Removed 3:13 antennas, cables, and palletes from burm
~2:50 Tested phase outputs. Reconnected loose BNC on Cos 5+6 output. Others were OK.
2:55 Cluster of storms over northern half of Yuma Co and extending northward.
3:30 Significant static field changes every ~5 secs. Some are nearly going offscale. Closest storm is near Idalia in Yuma Co.
4:11:10 1st gust front hit. Winds are moderate and out of ~NNE.
4:16 Severe thunderstorm warning issued for N. Yuma Co. until 5 UT (11 pm). Line of Severe storms indicated on radar.
4:17:23 -delta-E offscale
4:39 Flash rate is slowing
4:40 Closest storm is crossing into Kansas along the Yuma/Kit Carson Co. line. Motion is slowly to E and starting to move away.
4:50 Restarted "" script (autofetches satellite images, etc..) on It had stopped on August 3.
5:09 Receeding storm has dissipated.
~5:30 NWS issued small stream flood advisory for N. 1/3 of Yuma Co. Radar indicated that >2.5" of rain has fallen from ~stationary line of strong storms.
6:30 Storms to NNW are dissipating
6:33:00 Big +delta-E. +CG?
6:34:32 Small +delta-E
6:35:20 Significant +delta-E
6:45:36 Significant +delta-E
6:53 Discovered that Cos 4+5 was compressed (about a factor of 2 less dynamic range than normal).
? Checked phase gain/offsets. Cos 4+5 output changed during test, but was restored by wiggling board.
219 06-Aug 0:51 Cluster of storms in W. Kit Carson Co. and extending northward. Region of storms is approaching.
1:03:19 -delta-E at <-5 V (way off-scale)
1:07:15 Power outage. Slow antenna (SA) is very clean!
1:10:50 Starting "extreme sensitivity" experiment to look for possible quiet (positive leader) onset of discharges
1:14:40 Gust front hit
1:15 SA output is going wild because of high winds
1:18 Complete shut down due to lack-of-power.
1:20 Disconnected cables from grounding box (since not in use, no need to risk damage from lightning)
~2:45 Power finally restored.
~2:56:20 Bright flash followed several seconds later by rolling thunder. Following flash: power up electronics & reconnect cables.
3:03:58 +CG and nice field change at low SA gain setting
3:08:13 2 +CGs? Nice field change with 2 vertical steps.
~3:10 Called Yucca Ridge. Walt will check viewing conditions (reported later that there were patchy clouds)
3:25 Noticed that V.B. cables had not been reconnected to front of phase detector rack after power-up! #@!
~3:30 No field changes seen for a while. Region of storms moving off to east and decaying.
4:04 SA somewhat erratic. Due to bugs?
23:40 Cluster of storms in western half of Cheyenne Co. and in SW corner of Kit Carson Co. Closest cells are >80 km away.
220 07-Aug 0:10 Storms over southcentral Cheyenne Co. with weaker reflectivity region over W. Cheyenne Co. Additional storms further south.
0:22:19 Big -dEs. Artifact or real?
0:23 Significant +delta-E's are occurring every 1-2 minutes
0:24:59 Large +dE. Probably a +CG.
0:32:35 Long duration discharge. dE is first + and then - with a net -
0:32:43 +dE
0:34:50 +dE with 2 upward steps (2 +CGs?)
0:36:28 Complex static field changes (some negative steps) with a total duration of ~3 sec
0:39:56 +dE
0:40:49 Initially small +dE, then major -dE which almost goes offscale. Total duration is under ~2 sec.
0:45:27 +dE
0:46:09 +dE. Smaller +dE's follow at 10's of seconds apart.
0:55 Broken line of storms in Cheyenne Co. extending southward. Closest cell is nearly due south near Arapahoe. Broad region of weaker reflectivity trailing behind northern end of broken line and extending up into SC-SW Kit Carson Co.
1:21:47 Big +dE. Probably a +CG.
1:23 SA is wandering a bit. Winds are light, so insects may be at fault.
1:32 SA was cleaned. However, E-field is now offscale negative at gain of 7. This may be due to overhead anvil & precipitation.
1:36:17 Sigificant +dE. Probably a +CG.
1:38:12 +dE followed by -dE (net of about zero)
1:39:26 Static field going offscale negative, but recovering in less than 1 minute afterwards. Winds are light/moderate out of the south.
1:42:29 +dE followed by -dE (net negative dE)
1:(53-55) Took 3 digital pictures of sunset, mammatus clouds under anvil, and interferometer/SA/VB
3:23:40 +dE
3:24:19 Another significant +dE
3:26:57 -dE
3:28 A few additional field changes seen (from isolated cell?), then activity died
22:36 Took picture of cumulus congestus (possibly electrified) to N through NE
22:40-23:30 Setting up calibrator, testing power supply & cables, etc... Not monitoring congestus to N-NE, which may be too small to produce lightning.
~23:38 Took 2 pictures of calibrator to show its location (in wheat field, approx. 50 ft. directly West of parking spot)
23:45 Output of calibrator is terminated in 50 ohms near A/D board (via BNC T-connector), prior to start of data recording
23:50 No thunderstorms within at least 100 km range (see IR satellite image. NEXRAD images are unavailable from AWC)
221 08-Aug 0:10 Trigger rate is slow for Gain 7 at under 1 trigger/second (most triggers are probably from sources several hundred kilometers away)
0:30 Trigger rate is very slow for Gain 6: <1 trigger/10 secs
0:46 Trigger rate is also very slow for Gain 5, 10x, in spite of lower trigger threshold
0:58 Ditto for 100x, though somewhat faster than 10x (at same gain setting) due to more sensitive threshold
1:11 Trigger rate for Gain 4 is extremely low (hard to estimate)
~1:53 CG noted out of small convective region to West
1:56 Small +field changes (IC) noted every 20-30 secs, probably from storm to West (though another small convective region is to NNE)
1:58 Took digital pictures (one each) of convection to W and NNE
2:03:00 Took a digital picture of storm to W
2:03:12 Took a digital picture of storm? to NNE
2:16:37 Took a pix of storm to W
2:17:20 ...and of convection to NNE (receeding)
2:24:50 Took a pix of storm to W (backlit by waning sunset)
2:27:17 Small +field change
2:31:50 Took a pix of storm to W (backlit by waning sunset)
5:21 Output of signal generator is a square wave with the following properties: 1.1 V of 11 ms duration, -0.8 V for remaining 89 ms (100 ms period), and 1 microsecond transition times
5:49 Interpulse interval is now at about 0 V (instead of -0.8 V). Pulse is at about 1.4 V.
19:43:57 Took a picture of convection to SSW
23:47:30 Took a picture of convection to SE
23:50 Convection has maximum reflectivity of 60 dBz. and is located in NE corner of Wallace Co (SSE of Goodland, KS)
23:54:00 Took another picture of convection to SE
222 09-Aug 0:05:09 Ditto
0:16:00 Another picture of same convective region
0:26:00 ...and another picture. High reflectivity (now +56 dBz) persists in NE corner of Wallace Co, KS
0:42 Region to SE is decaying. No new convection for at least 10 minutes.
~22:00 Flash flood warning issued by NWS for Wichita Co. in Kansas. Radar estimate of 4" rain has fallen 10 mi. S of Leoti, KS
23:20 Closest storm is in SE Wallace Co at ~80 km range
223 10-Aug 0:09 Moderately strong winds are continuing to affect slow antenna and may at times produce >1 degree errors on Long VB pair
0:10 Broad region of precipitation with embedded convection to SE at >80 km range. Closest activity is in N. Greely Co.
1:20 Radar reflectivity to SE has been experiencing a general decay for almost an hour, though embedded convection continues
2:52:05 Discharge seen visually (sheet lightning) to SE, but only lasted ~1 sec. Visually, flash rate appears to be very low.
3:10 Broad region of significant precipitation extending from Greeley Co. KS east through Lane Co. KS and to the southeast. There continues to be embedded convection, which is primarily on the south side.
5:50 Region to SE has decayed considerably in past hour.
18:07 Restarted "" script (autofetches satellite images, etc..) on after zeus's system clock was finally corrected
21:29 Started a test of "", a script which uses gphoto for time-lapse photography via the Olympus C2000 digital camera
21:35 Stopped initial test. Time-lapse appears to work well. Interval between 640x480 images is 23-24 secs.
23 Working on antenna #6: No signal (see repair log)
23:07 Storm entering SE corner of Cheyenne Co. (to South). Is in FOV of Olympus C-2000Z
224 11-Aug 4:15 Storm with 50+ dBZ is just south of Burlington. Interferometer not operational since Receiver #6 is down.
~4:30 New storm to N and a bit W of Burlington
5:15:08 +dE offscale (estimate ~3 V)
5:23:00 +dE offscale (~2.5 V)
5:25:25 +dE
5:26:19 +dE
5:29:49 -dE
5:33:51 -dE offscale at about -4 V
5:47:28 +dE almost offscale
5:48:26 +dE offscale (~+4 V?)
? Antenna #6 mysteriously started working again
225 12-Aug 1:50 Storm to ~WSW in FOV of camera continues to produce -CGs (visible observation). Storm is near Seibert, CO
~2:40 Storm near Seibert has decayed to ~30 dBZ max relfectivity on NEXRAD radar (base scan) and diminishing rapidly
3:00 Closest storm is about 20 km north of Kit Carson in Cheyenne Co. Estimate range to storm is ~80 km
3:07 Next NEXRAD scan shows storm N of Kit Carson has max reflectivity of ~30 dBZ and is decaying rapidly.
3:53 On next NEXRAD scan after disarming system, evidence of a rapidly building line S. of Goodland was evident. This wasn't noticed until ~30 minutes later (when a NEXRAD animation was loaded)
~13 LMA was shut down and is no longer acquiring data.
20:00 East-West line of cumulus congestus forming over central Cheyenne Co. Max. reflectivity is ~25 dBz or less for most cells.
20:43 ~60 dBz reflectivity for cells over central Cheyenne Co. Closest is near Arapahoe, CO at ~60 km range. No significant static dE's.
21:33 Closest storm is near Cheyenne, Kit Carson, and Wallace (KS) Co. intersection on CO/KS border. Range is ~50 km.
22:15 Significant delta-E's are occurring every 5 seconds
22:30 Line of storms extending from N. Cheyenne Co. to SW corner of Kit Carson NE through KS near Goodland and on up into Nebraska
22:39 Significant static dE's are frequent. Occuring at least once every 2 seconds.
23:00 Line continues to intensify. Motion is nearly stationary (perhaps very slow northward component)
23:14 Flash rate continues to be very active. AM radio static is almost continuous.
23:52 Static dEs are starting to go off scale on Gain 7 more frequently (2-3 times a minute), but are mostly barely off scale (still OK)
226 13-Aug ~0:00 Tower at Goodland, KS office trailer was struck by lightning. "Thor" was destroyed, disabling the internet connection permanently.
0:38 Static dEs starting to go offscale on Gain 6
0:56:27 -dE offscale at -4.5 V
1:19 Buffer filling occassionally. ITFR may be responsible, since ITFR LED lights occassionally. Also, ftp transfer may contribute too...
1:58:33 Large +dE at Gain of 5. Much larger than -CG dEs. +CG?
2:01:59 Another large +dE and long duration flash. Probably a +CG.
2:12:10 Large +dE and long duration flash. +CG seen out window to ~East-northeast
2:29:20 +CG seen visually. Horizontally extensive below clouds are evident (spider lightning).
3:02:03 Horizontally extensive discharge. Was in FOV of camera.
4:03:17 Bright flash. Small static +dE.
227 14-Aug 5:55:50 Starting calibration procedure in which low light level video is used to capture images of foreground objects and background stars. The moon is nearly full, making foreground objects readily visible. Unfortunately, a region of clouds obscures stars to the W-NW-N
228 15-Aug 3:39 Additional calibration with low light level video is performed for W-NW-N, which is cloud free this time. However, significant haze attenuates the star light and the viewing conditions are further deteriorated by scattering of moonlight from a ~full moon.
? Calibrated log-RF sensitivity both at backplane and at receiver (see repair log)

Last Modified By: Mark Stanley ( )
Last Modified On: Monday, March 26, 2001  21:37:44