By Jacob Genuise
Key Messages:
- El Niño continues to intensify in the tropical Pacific.
- We are virtually guaranteed to have a very strong El Niño continue through this winter. Read a more detailed write up of possible impacts in our Climate Matters piece.
- The 1-month September outlook shows elevated chances of wetter than normal conditions statewide and slightly elevated chances of cooler than normal temperatures near Walla Walla and the Tri-Cities.
- The 3-month September-November outlook shows increased chances (50-60%) of warmer than normal temperatures and slightly elevated chances of below normal precipitation across most of the state aside from southwestern and far southeastern Washington.
ENSO strength probability forecast through May 2027.
El Niño has continued to strengthen in the tropical Pacific. There is now nearly a 100% chance of a very strong El Niño developing during the October-December period. This level of certainty in the development of such a strong event is rare, and it is increasingly likely (75% chance) that we will see a historic El Niño event this year. To learn more about what this may mean for Washington’s upcoming winter conditions, please read our Climate Matters piece which discusses this in much more detail.
1-month and 3-month Outlooks
1-month (September) outlook for temperature (left) and precipitation (right) in Washington State.
The 1-month outlook for September from the Climate Prediction Center shows indications of the first real pattern change we have seen in months. These outlooks now show increased chances of above normal precipitation statewide in September. Chances of wetter than normal conditions are highest across far southern Washington near Vancouver (50-60% chance) and decrease further to the northwest where chances of wetter than normal conditions are only slightly elevated (33-40%). As for temperatures, the September outlook shows only slightly elevated chances of cooler than normal conditions in southcentral Washington near the Tri-Cities and Walla Walla. The rest of the state has near equal chances of above, below, or near-normal temperatures.
3-month (September, October, November) outlook for temperature (left) and precipitation (right) in Washington State.
The 3-month outlook shows a higher confidence in the temperature outlook with a 50-60% chance of above normal temperatures statewide for the fall season. The precipitation outlook is less certain with slightly elevated chances (33-40%) of drier than normal conditions for all portions of the state aside from much of the outer Coast as well as southwestern and far southeastern Washington.