Sky-Guy,
I don't think the recent changes are as simple as "PDO+global warming", but it is a possibility. One of the really interesting things about the climate of the past few years is that it has brought us some incredible extremes-- recall the record snowfall winter of 1998/1999, the extreme drought of 2000/2001, some of the lowest summer streamflows on record this summer and fall, and then some of the highest flows ever recorded this fall. In the climate research business, we try to find patterns amid all this variation, and sometimes clear patterns are hard to find. The climate of the past few years, in my opinion, has been difficult to characterize in any simple way.