If your going to be fishing up river from the Hayward area you should be ok. From all the years fishing in the early season, I've never seen it get blown out. I've seen the water rise a little after some decent rains. It's expected to gradually warm up this weekend and into next, so you won't have a fast snow melt, which is good. I think we going to have a repeat of the good stonefly action we had a little more than a week ago when we got that really warm spell.
The uppers parts of the Nam has lots of riperian (wooded areas) and soft ground surrounding the rives, I believe thats how it's able to handle precipitation real well.
I know that if the weather hold up, I'll be down there next week for sure.