Topline:
Back in the spring it was looking like a strong La Niña was likely this fall, but now forecasters are saying that's quite unlikely.
Rain impacts: La Niña is often associated with drier conditions here in Southern California, but now we have one less atmospheric driver to consider.
Another influence to consider: A marine heatwave off the coast could juice storms and increase the amount of rainfall California experiences.
Back in the spring it was looking like a strong La Niña might shape up come late fall, but since then the odds have decreased quite a bit, as waters along the equatorial Pacific didn’t get as cool as anticipated and westerly trade winds failed to organize.
We pay close attention to the El Niño–Southern Oscillation, especially here in California, as it can affect our weather. La Niña is often associated with drier conditions in the southern half of the state.
Now that neutral or close to neutral conditions are likely, there’s no large-scale atmospheric driver connected to the tropical Pacific that we can use to try and bolster our guesses about how things might trend.
However, there’s another anomaly off the coast that could have an influence: a marine heat wave.
Off the northwest coast of California, waters are about 1 to 1.5 degrees celsius above normal. And it’s possible that as storms pass over the blob, the additional moisture evaporating from the ocean into the atmosphere could feed the storms and increase the amount of rain that falls.