by Alex Reinecke
Report written by Qingfang Jiang, Monday, April 20
Synoptic overview:
A cyclone is located off of Washington, which brings northwesterly flow into the Eastern Sierra and Owens Valley through April 20 and 21. GFS forecast mountain top wind speed is around 20-25 knots. Wave responses are expected in the valley.
The plan of operations for IOP 14 on April 20-21:
1. MAPR: on all the time
2. MISS: on all the time
3. Sounding launches from MAPR at 12 UTC 20 April and 00 UTC and 06 UTC 21 April
4. Sounding launches from MGLASS at 12 UTC 20 April and 00 UTC and 06 UTC 21 April
5. Lemoore: no activity
Summary of operations and observations:
Approximately from 1300 PST 20 April to the end of IOP 14, fairly strong westerly or northwesterly wind was observed in the valley. The gust maximum reached 64 mph according to surface network station 1. Strong westerly wind was documented by MISS and MAPR as well. Strong surface wind caused some problems in balloon launches at the MAPR site. MAPR also indicated moderate descent below 4 km between 06 UTC and 11 UTC. Radiosondes launched from MAPR (0100 UTC and 0644 UTC) and MGLASS (0602 UTC) showed an inversion between 500 mb and 600 mb and westerly wind of approximately 35 knots at the ridge top level (approximately 700 mb).
by Alex Reinecke
In the afternoon and early evening, wave clouds were clearly seen in the valley from both Bishop and Independence. A gap located along the lee of the main Sierra ridge separated the upstream clouds and lee-side clouds. Clouds over the valley included high cirrus, altocumulus, and lower-level lenticular clouds. Downstream of the gap (similar to Foehn gap in the Alps), two or three lenticular clouds can be seen across the valley.
Dust devils were seen near the MAPR site. However, no easterly winds were observed in the valley.
by Alex Reinecke