Report written by Vanda Grubisic, Friday, March 12
Synoptic overview:
With the short wave, which generated the easterly winds documented during IOP2, moving to the southeast, the Eta and COAMPS models were forecasting a short period of westerly winds over the Owens Valley. Based on the 12 UTC March 11 Eta run, generally weak westerly winds at 700 mb and 500 mb would be present from 12 UTC (4 PST) on Mar 12 turning into N-NNE winds by 06 UTC (22 PST) March 13.
The plan of operations for IOP 3 on March 12:
1. MAPR: on all the time, radiosonde launch at 18 UTC (10 PST)
2. MISS: to be located at its base at Independence airport, if possible run through the night from Thursday to Friday
3. MGLASS: launch a radiosonde from Merced at 18 UTC
4. Lemoore: no activity
Summary of operations and observations:
This was a weak westerly wind event that was already in progress when the MISS was turned on at 00 UTC March 12 (16 PST March 11). The MISS operated throughout the night at the airport location , and documented westerly winds up to 7.5 knots above 2 km. The maximum height of the MISS returns was 2.5 km, decreasing to 1.5 km by the end of the IOP at 19 UTC (11 PST). Winds below the mountain height were generally southerly during the night, turning into northerly and significantly weakening during the day. MAPR was down during the night, due to another instrument failure, and was turned on at 15 UTC for the beginning of the IOP. Obtained winds at the MAPR site were consistent with those at MISS.
The radiosonde was launched from the MAPR site at 18 UTC (10 PST). The sounding showed a shallow inversion at 950 mb with very weak winds below 600 mb, and 10 m/s and higher NW winds above that level. The planned MGLASS radiosonde launch was canceled because the new analysis for 12 UTC March 12 was already showing NW winds at 500 mb over the Central Valley.