Report written by Jim Doyle, Sunday, April 4
Synoptic overview:
A cutoff low pressure region was present to the south of the Sierra resulting in deep easterly flow about the crests of the Inyo, White, and Sierra Mountains. Northerly flow was present in Owens Valley associated with the pressure gradient along the valley. Owens Valley was in a region of cyclonic curvature with low-level moisture present that was conducive for low clouds and occasional shower activity.
The plan of operations for IOP 10 on April 02:
1. MAPR: on all the time
2. MISS: on all the time, located at the Independence Airport, one radiosonde launched at 1800 UTC April 2
3. MGLASS: no activity
4. Lemoore: no activity
Summary of operations and observations:
This event was dominated by easterly flow capping a shallow northerly flow in the valley. The valley was mostly overcast on April 2. Sporadic lenticular clouds and small clearing areas could be seen over the Inyo Mountains. Visible satellite imagery was suggestive of trapped waves in the lee of the Inyos, Whites, and Sierras along the western slopes.
by James Doyle
MISS was located at the Independence airport and documented easterly flow above 1.5-2 km of varying strength from less than 10 m/s to more than 20 m/s.
The radiosonde launched from MISS at 1800 UTC 2 April showed shallow northerly flow present below 700 mb with easterlies increasing in strength above. Several shallow inversions were present in the easterly flow.
MAPR documented northerly winds early on April 2 that transitioned to easterly flow above 2 km.
Wave activity was not obviously apparent in the vertical velocity data from the MAPR and MISS. Occasionally strong signal to noise ratio features appeared to correspond to virga and precipitation that was present in the valley. The precipitation enhances the scattering and yields horizontal velocities to higher altitudes, in some cases to 5 km.
Moderate northerly winds were documented by the ground network stations in the layer beneath the easterly flow.