I can't speak for Emily, but I think it's a good question, and I think the MJO interference may be a contributor to the dry start to California's winter. However, I don't see an obvious smoking gun that points to the MJO as the primary culprit. 

The situation is sort of like last year but for El Nino this time - the atmospheric circulation has looked pretty similar to what we expect for El Nino, but the anomalous Aleutian low has been displaced a bit north and west of what's typical, and the west has seen more atmospheric ridging than usual. That's what's so tricky about California precipitation - it's sensitive to these details. In any case, perhaps the situation will change if we get some constructive interference between the MJO and El Nino signal.