An 85F+ day is appearing likely tomorrow for most metro areas along the west coast. Seattle's summit thus far in 2026 is 82F, set on 5/12. It's looking likely that we beat that mark.
Then overnight, a very weak, very marginal midlevel threat manifests itself Seattle north, particularly around BLI and Vancouver BC. I wouldn't expect any lightning out of this low capped fluff, but if there is any, it'll most definitely be of the one clap wonder variety, and probably in BC.
The nature of the disturbance involved has been in flux on the models. If it cuts off a touch better as to allow for slightly more negative tilting, the risk for an isolated thunderstorm or two would increase a bit. When living west of the Cascades, where we get seven thunderstorms a year, one has to pay attention to every little risk, no matter how close it is to being a non-event.