That was a nice pivot from telling me that the CC equation is irrelevant to climate science to pretending like I’m playing catchup to you.
Your second paragraph is the justification why we model climate change and why it is modeled with a wide variance of configurations. Otherwise we could just take our current precip and multiply it by 1.015 per degree C and be good.
I think the climate models have more skill than you give them credit for, but that’s probably not worth debating at this time.
Now we’re getting somewhere. Yes, this is (generally) correct. But the keyword is GLOBAL.
You can’t apply the same logic to individual regions. Because there will be spatiotemporal variability in general circulation(s)/weather patterns, convection/clouds/albedo, and all relevant transports/fluxes/conversions of sensible+differential heating.
So exactly how precipitation will change in the PNW, specifically, and at what time(s) of year, cannot be ascertained. Though predictions can be made with a low (but nonzero) degree of skill.
Again as I have mentioned many times now... we had a newborn baby and my wife's main complaint was the relentless rain from mid May through mid June. The morning clouds definitely kept the temps down but there was plenty of sun in July and August that year as the satellite loop shows. Also having a nasty 4th of July added to the overall complaining about that summer from the general public. I hope we can manage less low cloudiness this year if the patterns are similar.
One additional note... Cliff wrote about people complaining about smoke that summer! So our local weather did not prevent smoke coming in from other areas. This makes sense to me.