IOP 4: 1-2 December 2001

Time Period of IOP

1200 UTC 1 Dec-0000 UTC 2 Dec

Overview of IOP

 Postfrontal conditions prevailed following the third short wave trough (described above). The satellite infrared sequence shows the convective cloudiness passing over the radar area (Fig. 1a, Fig. 1b, Fig. 1c).  The P-3 aircraft flew a mission this day.  When the aircraft arrived in the S-Pol radar area from 1500-1600 UTC 1 December 2001, the back portion of the frontal precipitation was over the mountains to the east (Fig. 2a, Fig. 2b). The ETL S-band profiler showed convective cells (as described above (Fig. 3). For about two hours (~1600-1800 UTC) the aircraft executed a dual-Doppler radar pattern in the moderately intense postfrontal precipitation over the mountains east of the S-Pol radar (Fig. 2c, Fig. 2d). At 1907 UTC the S-Pol particle identification algorithm indicated graupel at or just above the melting level over an extensive region (Fig. 4). From ~1900-2100 UTC the aircraft executed a microphysical sampling pattern (Fig. 2e, Fig. 2f, Fig. 2g, Fig. 2h). The P-3 left the study region at about 2100 UTC.

Convair-580 Summary

UW Flight Number:

   1894

Period of Flight:

   1456-1656 UTC, 1 December 2001

Main Accomplishment of Flight:

Convair-580 returned to Paine Field just after crossing the Columbia River due to instrument cockpit problems.

Instrument Problems:

-

Flight Scientist:

Peter V. Hobbs

Approximate UTC Timeline (Local time= UTC-8 hours) Activity for UW Flight 1894:

P-3 Summary

P-3 Flight Number:

   011201H, Improve 02

Period of Flight:

   1456 UTC 1 December-? UTC 1 December 2001

Main Accomplishment of Flight:

The P-3 took dual-Doppler measurements in intense postfrontal precipitation.

Instrument Problems:

-

Flight Scientist:

Nick Bond

Approximate UTC Timeline (Local time= UTC-8 hours) Activity for P-3 Flight 02:

Engine Start

Block Out

Takeoff

145652 UTC (47.91171, -122.28354) 7.621°, 965.3 mb, 1255.0 m taxiing

rain before takeoff

150438 UTC (47.87386, -122.31438) 237.682°, 923.3 mb, 402.0 m  takeoff

150729 UTC (47.79729, -122.49591) 225.594°, 812.3 mb, 1568.0 m  in mod snow

151348 UTC (47.48796, -122.65120) 199.355°, 609.9 mb, 3709.0 m  in clear air ci above

152455 UTC (46.82231, -122.96526) 194.306°, 553.2 mb, 4461.0 m  in higher cloud layer

152834 UTC (46.61064, -123.03784) 192.813°, 553.6 mb, 4391.0 m  in clear air again

152931 UTC (46.55721, -123.05576) 192.804°, 553.6 mb, 4107.0 m  back in cloud

154012 UTC (45.90298, -123.03680) 174.783°, 558.6 mb, 4013.0 m  in clear after light jolt in and out of clouds

154645 UTC (45.47778, -122.97495) 139.437°, 575.8 mb, 4208.0 m  descending into clouds

155657 UTC (45.15850, -123.00327) 185.158°, 794.1 mb, 1745.0 m  tail radar indicates good convection to west

171047 UTC (43.77438, -121.83636) 94.728°, 607.6 mb, 2571.0 m  broke out on top - sunshine!

181936 UTC (44.14136, -122.50940) 61.082°, 538.1 mb, 4178.0 m  in cloud..

62) 242.829°, 557.1 mb, 3875.0 m  broken layer below, scattered clouds at flight level

205749 UTC (45.97282, -123.09065) 355.921°, 466.3 mb, 5413.0 m  NW of Portland at 20K, between layers

S-Pol Radar Summary

 The S-Pol radar was run continuously in the same mode of operation for the length of the field project.

Summary of Mobile Upstream Sonde Launches

Launch times at: Creswell, OR, Lat: 43.9200, Lon: -123.0250, Elev: 165 m

1700 UTC 1 Dec

1913 UTC 1 Dec

2229 UTC 1 Dec

Summary of Leeside Sonde Launches

Launch times at: Black Butte Ranch, OR (a.k.a. ISS-3), Lat: 44.379, Lon: -121.679, Elev: 1027 m

1455 UTC 1 Dec

1755 UTC 1 Dec

2055 UTC 1 Dec

Summary of NWS Sonde Launches from Salem (SLE)

Launch times:

1200 UTC 1 Dec (standard)

1500 UTC 1 Dec (special)

1800 UTC 1 Dec (special)

2100 UTC 1 Dec (special)

0000 UTC 2 Dec (standard)

Summary of Snow Crystal Ground Measurements

Measurement times:Every 15 minutes from

1500 UTC 1 Dec-2245 UTC 1 Dec (at Santiam Pass, Corbett, and Tombstone Sno Park)