It is interesting to say the least. The thing is the Chehalis is mostly rain fed run off and not snow which makes it nearly totally different than snow fed streams for out migrants. This bit of hot weather shows how. Hit the link I provided and look for the yellow and green dot streams and they are at beginning flood stage from the snow melt. As you said RG water conditions make a big difference and in the snow fed streams warm weather speeds up the melt which reduces the normal flows later on. Everything is connected one way or another it is just the same but different everyplace. Either way if the long range forecast holds this will be a bad year for juvenile salmon in the rearing areas.