Yes, whatever the insulation, keep it dry at all costs! Both synthetic and down are equally COLD when wet! (Been there, done that, don't recommend it!) The only difference is that it's a bit easier to dry a soggy synthetic bag than a soggy down bag. For the latter, you have to pull apart clumps in the down as it dries. A clothes dryer is a distinct advantage, but not exactly something you'd carry in your backpack!
Note that a high-quality down bag, well-cared for, lasts about 3 times longer than synthetic. That's because synthetic insulation loses its loft sooner after being compressed multiple times. Cost per year of life is not much difference between a $400 down bag and a $180 synthetic. Of course a lot depends on if you have the cash up front--credit card interest will make either bag twice as expensive.
The one place synthetic has a slight advantage is in case of a week of continuous rain (which we do get in the PNW in winter), when there is no chance at all to air out the bag. Synthetic will keep its loft longer under those conditions, while down will absorb moisture from the air and from your body and gradually lose its loft. This won't matter unless you'll be out 3 nights or longer and there are no "sunbreaks" during the day when you can stop and air your sleeping bag for half an hour.
If you are new at backpacking under wet conditions, a synthetic bag, although heavier, might be better until you become more proficient at keeping everything dry. Practice in your back yard or at a state park under soggy conditions is a good way to gain this proficiency, although it takes a lot more will power when either the car or your warm bed is only a few feet away!