WX-Walt Rogers weather assessment Day 1

DAY 1 Mon 6-14-21 - Wx assessment by Walt Rogers

A Spring almost Winter like pattern prevailed on the day as a 500mb trough moved inland from just off the CA OR coast. Tems were 25-35 DegF below normal. Overnight a dissipating front moved over Northern California. A moist conditionally unstable airmass triggered to heavy cu bases 8.5-9.5k msl by late morning. By mid afternoon coverage ranged from 40pct to 90pct with numerous very light showers. Late afternoon triggered isolated small CB tops 20k msl… peaking with showers 5-7pm local time. Two lines formed from the wind shears NNW-SSE over the Mt Shasta to Montague valley. Surface and low level winds were 155deg to 190deg 15-20kts… turning o 215deg 30kts and higher starting at 10k msl. It was a very dynamic (...and somewhat risky) day for soaring with rapid changing conditions as the showers spread over the task area (video is included showing radar and 0.5km visible GOES imagery). A convergence zone developed E-W just south of Siskiyou County airport late in the day as low level N wind 10-15kts entered the north valley. That allowed most pilots to climb out and entered the AAT circle of Deer Mtn 40km away. Centering and finding thermals below 7k msl (airport at 2.6k msl) was difficult and choppy resulting in much search. With a narrow height ban of 2-3k feet inevitably… one got low on the task requiring careful planning.

Mon 6-15 DAY1 I've included below satellite and radar video URLs

https://www.dropbox.com/s/jp8rnr71b6flbgq/Video_GOES_Sat_DAY1_20210614.mp4?raw=1

https://www.dropbox.com/s/95qvp1bqi47k3mt/Video_Radar_DAY1_20210614.mp4?raw=1