The El Niño weather forecast got sharper Thursday: the National Oceanic and Atmospheric Administration’s Climate Prediction Center said there is a 97% chance the pattern will be strong or very strong through December. For Southern California, that keeps above-average rainfall in play as winter approaches.
Jon Gottschalck, the Climate Prediction Center’s operational prediction branch chief, said the setup starts with warm water moving east across the Pacific Ocean. “Basically, it’s a wave in the ocean that will bring warm water from the western Pacific to the central and eastern Pacific.”
Southern California and the winter setup
A strong El Niño significantly tilts the odds of expected weather outcomes during winter. Ariel Cohen, a meteorologist with the National Weather Service in Oxnard, said it can bring more stormy weather than usual to Southern California, Texas and Florida. The same pattern can raise the risk of heat waves on land and at sea.
The Climate Prediction Center also put the chance of a very strong El Niño at 81% over the same three-month period ending this December. Very strong El Niños have been called super El Niños, and the forecast now puts that stronger tier well within reach.
Pacific Ocean monitoring
El Niño usually lasts nine to 12 months and typically shows up every two to seven years, which is why Thursday’s update matters now rather than later. It is marked by warmer water in the central and eastern tropical Pacific Ocean, along with shifting atmospheric conditions and weakening east-to-west trade winds along the equator.
When those winds weaken, a downwelling oceanic Kelvin wave can move warm water from the western Pacific to the central and eastern Pacific. That is the mechanism behind the forecast, and it is why scientists will keep watching the Pacific Ocean as El Niño develops through December. Predicting the weather is always tricky, and even solid forecasts sometimes do not live up to the hype.
California rainfall risk
For Southern California, the practical takeaway is the same one forecasters keep signaling: a stronger El Niño raises the chance of wetter winter weather and the risks that come with it. Last month, authorities declared the arrival of El Niño, and Thursday’s update pushed the odds toward a stronger pattern that could shape the winter ahead.
