I figured out what happened.
The cloud quilt is so vast continuing west straight over the foothills, covering evenly the mountains behind them and still just that evenly covering the mountains behind those, that it actually follows the curve of the earth at least the portion of arc of our viewing, to the end of the state perhaps, maybe even through Utah. The sun never does slip under the clouds, can never illuminate from beneath them as usual so it stays concealed behind the cloud screen all the way down to darkness. Our down. The clouds could clear by the time the edge of night reaches California where the clouds may break and the sun shine through beneath as it as the earth rotates away from it.
These are somebody else's clouds I'm using to show the sun going down with no color, like Planet Dreary.
The next day, yesterday, breaks in the cloud cover allow the usual glorious thing. With the window open the light show demands your attention.
Conclusion: No breaks in clouds mean dreary sunsets.