Summary:
- August was warm early and late but cool in the middle…the result was slightly below average to slightly above average conditions for most, with the southwest seeing the warmest temperatures for the month.
- Dry to wet mix across the west. Monsoon moisture in the Four Corners and Rockies, wet northern California, western Oregon and Washington, dry central to southern California and into the Great Basin. Humidity levels were elevated during August due to periods of southwesterly and onshore flow.
- Growing degree-day accumulations remain above average for most with coastal areas of California and some inland areas of the PNW closer to average.
- The September forecast has a short burst of onshore flow out of the Gulf of Alaska, then warm, warm, warm till mid-month at least. Many locations could hit the high 90s or low 100s. No widespread precipitation in the forecast through mid-month or later, although a slight chance exists in the far northwestern areas of the PNW later in the month but too early to have confidence in the when, where, and how much.
- The 90-day seasonal forecast has the western US titled toward warm for most of the region. Precipitation amounts are forecast to be near average to slightly above in the PNW and below average in the south and southwest.
- It looks more likely that ENSO-neutral is with us most of this winter and that any La Niña development might be on the weak side or a bust. The Pacific Decadal Oscillation continues in a strongly negative state, adding to a warm fall potential, but also increasing the likelihood of a cold, wet winter.
