The weak La Nina that Alaska has been sitting under is fading fast. Subsurface ocean temperatures in the critical Nino 3.4 region of the central Pacific show a massive reservoir of warm water building below the surface, with essentially no cool water left to replace it. La Nina, as the National Weather Service put it, is dying a slow and painful death.
By June, July, and August, forecasters put the odds of an established El Nino above 50 percent, with confidence increasing further into fall. How strong it gets is still an open question, but a modest to strong event is considered a real possibility.
For Alaska, the summer signal is actually the strongest of any season, which surprises a lot of people. In weak El Nino summers, temperatures across the entire state have averaged roughly one degree above normal. That may not sound dramatic, but with less natural variability in summer compared to winter, one degree carries more weight. Precipitation patterns tend to favor drier conditions across the interior and southeast, with slightly wetter conditions along the western coast and Alaska Peninsula.
Fire is the big wildcard. Two of Alaska’s four largest fire years on record occurred during weak El Nino summers, though median acreage burned in those years was not dramatically elevated due to high variability across the composite.
The NWS was careful to note that El Nino explains only about 20 to 25 percent of any season’s climate variability. It is a thumb on the scale, not a guarantee. Expect more updates as the Climate Prediction Center releases its next seasonal outlook.
