There are general expected weather impacts of El Nino vs. La Nina. This occurs mostly because the pressure differential at the equator of the Pacific Ocean impacts the position of the jet stream that pushes/guides storms across the Northern Pacific. Normally, El Nino conditions bring warmer, drier conditions to the PNW, and wetter, stormier conditions to California (and suppression of Atlantic hurricanes and augmentation of Pacific hurricanes). And La Nina conditions bring the reverse. While I was in gradual school at UCSB in the 80's, we experienced two strong El Ninos (82-83 and 86-87) that brought floods, massive storms, and disruptions of coastal upwelling that had huge impacts on kelp forests in Souther California. You can find information from the NWS climate prediction center
here through on the temperature and rainfall tendencies expected through the end of December (and further out too by selecting a different lead period). [And see some historical data on coldest winter temperatures vs. El Nino / La Nina strength
here. So, it wouldn't be a great winter to purchase a season ski pass, one would expect.
BUT these are general trends and some years can be wildly out of whack with these general weather predictions. For example, last summer was a La Nina which typically brings dry weather to California. But there were rains from one end of the state to the other breaking a long period of drought and filling their reservoirs.
Steve