National Weather Service Updates El Niño Advisory Ahead of Winter
Strengthening El Niño could mean a warmer winter, less lowland snow and implications for Olympic Mountain snowpack and the Dungeness River.
By R.E. Carlino | The Sequim Post
The National Oceanic and Atmospheric Administration (NOAA) first publicly forecast the possibility of a strong El Niño on March 12, 2026, but its confidence increased substantially over the following months. NOAA has now reported that a very strong El Niño is underway in the tropical Pacific and is expected to persist into spring 2027. El Niño is not a storm—it is an unusually large-scale warming of the Pacific Ocean large enough to rearrange weather across the planet.
As El Niño continues to strengthen, NOAA's October outlook places the probability of strong-to-very-strong conditions persisting through January–March 2027 at more than 83%.
NOAA's latest diagnostic discussion reports:
- Niño-3.4 sea-surface temperature anomaly: +2.1°C.
- Some eastern equatorial Pacific waters: more than 4°C above average.
- Continued strengthening of oceanic and atmospheric El Niño conditions.
What this means for Sequim
A powerful El Niño increases concern about warmer-than-normal winter conditions and reduced mountain snow accumulation, although it does not determine the outcome of individual storms.
For the Dungeness Valley, the issues to track are:
- Olympic snowpack: Whether precipitation accumulates as snow or falls as rain.
- Summer 2027 water supply: Potential consequences for Dungeness River runoff and irrigation.
- Lowland snow: Warmer seasonal conditions could reduce the frequency of lowland snowfall, but significant snow events remain possible.
Actual Olympic Mountain snow-water-equivalent measurements have not been established in the Prediction Center's latest edition. The seasonal forecast is not evidence that the coming winter will be snow-free.
Potential effects on fisheries
El Niño's effects extend well beyond changes in weather. NOAA Fisheries has drawn upon historic observations and data collected in previous El Niño events to anticipate likely impacts on marine environment across the United States.
Warmer ocean temperatures can alter marine ecosystems and shift fish populations and commercial fishing opportunities. In Southern California, fishermen are already reporting increased catches of warm-water species such as wahoo, striped marlin and yellowfin tuna, typically found farther south. El Niño can also shift tuna habitat eastward across the Pacific, while changes in ocean temperatures and rainfall may affect fisheries and aquaculture from Alaska to the Gulf Coast. NOAA cautions, however, that the timing and extent of these impacts remain uncertain and vary considerably by region and species.
Related sources:
NOAA — October 8 ENSO Diagnostic Discussion
How Will El Niño Affect Your Local Fisheries?
