Report written by Qingfang Jiang, Thursday, April 22
Synoptic overview:
A trough is located to the east of California which brings in strong northwesterly flow over the observed area during April 21 and 22. An IOP is declared from 21 UTC 21 April to 18 UTC 22 April to document this northwesterly event.
The plan of operations for IOP 15 on April 21-22:
1. MAPR: on all the time
2. MISS: on all the time
3. Sounding launches from the MAPR site: 21 UTC 21 April, 00, 06, 12 UTC 22 April
4. Sounding launches from MGLASS: 21 UTC 21 April (Fresno), 00, 06, 12 UTC 22 April (Chowchilla)
5. Lemoore: no activity
Summary of operations and observations:
This event featured strong northwesterly flow over the observed area. Both upstream soundings and soundings from the valley showed strong northwesterly wind above the 700 mb level and an inversion between 500-600 mb. The 00 UTC 22 April MAPR sounding showed strong northwesterly wind (approximately 30 knots) down to 800 mb and a nearly 500 m descent of the sonde near the 500 mb level. MAPR also documented air descent in the lowest 3 km between 03 and 03 UTC (April 22). The surface network showed fairly strong northwesterly gusts in the valley in the afternoon and evening of 21 April. At station 1, the northwesterly wind reached 61 mph around 20 PST. In the valley, the wind changed to northerly at 20-22 PST.
The air was fairly dry and few clouds were seen from the valley in the afternoon of April 21 and the early morning of April 22, except for a small fraction of cirrus and cumulus. In the afternoon of April 21 (approximately 14 PDT), it was hazy in the valley between Big Pine and Bishop. Considering the time and wind condition, the dust was likely associated with convection.
White Mountains; between Big Pine and Bishop
0800 UTC
by Alex Reinecke