Debris Flow-2006/2007 Event Log

IOP-9

Lat: 34.660301 N Lon: -118.764008 W Alt: 814 m Truck HD: 91 deg

Date/Time SR1 ready for operation: 19 April 2007 2105 UTC

Note taker: David Jorgensen (NSSL)

Time (UTC)	Event
2020	Arrived on site – leveled truck – set time (computer time was about 2.5 hrs off
2105	Scanned a couple of volume scans – no echo – shut down system to go check in at the hotel and monitor KVTX from there. Rain not expected till early tomorrow morning.
20 Apr 0545	Releveled truck - Started data collection – weak upper level echoes around burn area
0652	Stratiform echo thickening – no convective type cells evident
0700	Moderate stratiform echo over WTK ~35 dBZ
0812	a little bright band evident on the 10+ deg tilts near WTK – echo decreasing in areal coverage to the west – probably end of this first band of precip
0902	Line of weak storms to the south to near WTK – moving to the east fast
1002	Overall echo strength definitely decreasing all around
1127	All echoes nearly gone all quads
1337	Rain strength increasing again over the burn area – see some echoes of ~45 dBZ between site and WTK
1345	Light sprinkles at site
1522	Releveled truck – passenger side just slightly low and nose slightly down (+/- 0.05 deg or so)
1517	Rign of bright band on the 8 deg tilts around 5 km in range – freezing level must be lowering!
1528	Strong bright band on 10 deg tilt just aloft
1540	Backing up data to the laptop – got data through 1540 UTC
1547	Moderate intensity rain near Whitaker peak ~45 dBZ max
1623	Fairly strong bright band now - ~ 50 dBZ only a few km in range on the 10+ degree elevation sweeps
1653	Bright band now ~55 dBZ
1700	Moderate rainfall at site
1722	Rain has picked up again at site
1758	Rain slacking off a bit at site
2015	Precip over the burn area (and at the site) becoming intermittent – main body of frontal precip still offshore and moving south. Still expect some convective type showers to develop as the really cold air aloft moves overhead and provides more instability
2053	Sun breaking out!
2139	Screen now pretty much devoid of echoes. Will wait a few more hours to see if enough surface heating generate some convective storms in the mountains.
2200	Releveled truck. Passenger side too low by 0.05 deg. or so
2204	When the clouds break over the mountain peaks the peaks are covered in snow
2216	Light rain at site again
2220	Convective cells beginning to build over the burn area
2246	Rain stopped – sun out again
2332	Echoes diminishing – may be getting close to the end of data collection – only small cells remaining over extreme west part of burn area – max dBZ only about 40
0000	Shutting down