Debris Flow-06/07 Event
Log
IOP-3
Lat: 34.66030 N Lon:
-118.7640 W Alt:
814 m Truck
HD: 91 deg
Date/Time SR1 ready for operation: 1/30/07 1600 UTC
Note takers: David Jorgensen (NSSL) & JJ
Gourley (NSSL)
|
Time (UTC) |
Event |
|
1530 |
Arrived on site – leveled truck, booted computer
– all OK |
|
1628 |
Began data collection- no echoes on screen, skies clear
sun out at site. NWS calling for increasing precip as upper cut off low moves
eastward. Tstms possible as CAPE has increased due to cold air aloft in the
cutoff. |
|
1728 |
Light echoes to the north at upper elevs – probably
alto stratus – no echoes over burn area |
|
1857 |
Releveled truck – right side had slipped down
perhaps 0.1 deg |
|
1859 |
Few very light echoes now very western end of burn area on
10 deg scan |
|
1929 |
Lowered Vr threshold to 3 to reduce amount of Vr=0 weather
data thrown away by the clutter filter |
|
1952 |
Large mass of echo 40-50 km to S of radar to 40 dbz.
Nothing over burn area. No echo discontinuities caused by clutter filter so
far |
|
2007 |
Echo mass to south ~40 km getting stronger, now max dBZ
~50 |
|
2048 |
Echo mass to south now max dBZ ~55 and much larger |
|
2049 |
A few very weak echoes over burn area |
|
2057 |
All scans backed up to laptop - 1528-2050 UTC |
|
2135 |
Gourley on site |
|
2136 |
Checked file sizes on computer and noticed 4 volume scans
from 1840-1855 UTC were nearly 3 Mb big, about 3 times larger than the other
files. Corrupt data files?? |
|
2151 |
First raindrops have fallen at the radar site |
|
2202 |
Echoes > 55 dBZ have just entered the SE tip of the
burn area. Another small Tstorm
is evident about 10-15 km to the SW, within the burn area. |
|
2223 |
Echo intensities have decreased down to < 40 dBZ in SE
tip of burn area. Rain has also
stopped at the radar site. |
|
2328 |
Precipitation over the basin has nearly disappeared. Only 10-15 dBZ echoes remain. |
|
0053 |
I releveled the truck. The back side had slipped down about 0.1 deg. Visibility has improved near the lake
and only very weak (< 15 dBZ) echoes remain in the vicinity. |
|
0148 |
Echoes ~35 dBZ are now visible in the extreme E portion of
the burn area. |
|
0204 |
Very light rain, only detectable by face (not hands), has
begun at radar site. |
|
0208 |
Weak echoes (~25 dBZ) are now showing up in W parts of
burn area at elevation angles near 6.5 deg. |
|
0240 |
Jorgensen back on site |
|
0242 |
30-35 dbz echo over Whitaker USGS site on 5 deg scan |
|
0313 |
45 dBZ cell about 5 km SSE of the radar |
|
0559 |
Noticed some holes in reflectivity field at 19.5 deg due
to Vr notch filter. May require
some additional adjustment of parameter settings. |
|
0605 |
Changed Vr notch filter down to 2 m/s. More ground returns are noted in
reflectivity field. Spiral
pattern of missing data still evident at 15.6 deg though. |
|
0610 |
Changed Vr notch filter down to 1 m/s. Significant amount of ground clutter
entering reflectivity images at low tilts. Very little to no data thrown out at upper tilts (> 6.5
deg). |
|
0615 |
Decided to switch back to 2 m/s for notch filter. |
|
0723 |
Stratiform echoes with reflectivies ~35 dBZ occupy E 1/3
of burn area. Bright band very
clear in dBZ field. |
|
0800 |
Data collection has ended. |
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