Summary:
- A warmer than average* November was experienced over much of the west, with portions of western Washington and western valleys south into California seeing closer to average temperatures.
- After the deluge in California from an atmospheric river in October, the storm axis moved north bringing another extreme atmospheric river event that inundated Washington and British Columbia. Otherwise, the west experienced a very dry November.
- Drought conditions have improved in the PNW but remains in place for over 95% of the western US. The winter forecast points to continued improvement for the PNW across the northern Rockies but little change elsewhere.
- The December forecast favors a continuation of the cooler than average to average conditions seen in late November. The storm track also continues to be more northerly, keeping the PNW wetter than average and California likely closer to average or below average.
- La Niña conditions continue in the Tropical Pacific with models pointing to the conditions staying in place through mid-spring, then transitioning back to neutral in late spring to early summer. With La Niña conditions in place, the overall forecast is bolstered to the PNW likely continuing to experience a cooler/wetter winter, while California is more likely to be drier with near-average temperatures during the winter. The transition line is the unknown, but it appears that northern California is the likely pivot point.
*Note that all references to normal or averages in this report are to the 1981-2010 climate normal for each weather/climate parameter unless stated otherwise. Also, note that the 1991-2020 climate normals are starting to become available across reporting agencies and will be used in this report when possible.
