Forecasters see wet El Niño ahead, with January possibly doubling normal rain Play

We are getting the first long-range forecasts of just how much rain Malibu could get from the approaching El Niño storms. January may be the wettest month.

We usually get 3 and a third inches of rain in January. This year it looks like we might get almost double that — 6 and a half inches.

Ready for some numbers? Ocean temperatures in the Pacific close to Peru have climbed more than 5 degrees above average. Some El Niños are like that, and when the hottest water is just off the coast of Peru, California gets slammed. When the hottest water is out in the middle of the Pacific, we get a dry El Niño.

The pattern right now gives California a 3-1 chance of this El Niño exceeding every event since 1950. But remember: the forecasters are explicit. More likely doesn't mean guaranteed.

The European Centre for Medium-Range Weather Forecasts runs its forecast 51 times, each starting from slightly different conditions. Averaging those runs gives a more useful picture than any single one.

The consensus now is that there is a significant similarity between this event and two prior very strong El Niños that drenched California. And there are also differences showing up from two El Niños that were dry.

The hot water off Peru creates giant thunderstorms that influence the position of the storm track — the jet stream — over us. That's because distant tropical thunderstorms transfer heat from the ocean to the atmosphere through convection.

Right now, the pattern is even worse than in 1983 and 1998, when Malibu got smacked, PCH covered in mud, and houses fell into the ocean.

But there is one big question. The ocean water off Malibu is much, much warmer than it ever has been. It's possible that historically warm oceans up here could weaken the storm track or steer it away from California. But more likely, the record-setting ocean temperatures could add extra heat and moisture to any storms that do aim toward California.

And we do not know how the warm temperatures will affect snowfall in the Sierra Nevada. The latest European forecast says Mammoth Lakes could get an extra 5 inches of precipitation this January. Notice we did not say snow — it might fall as rain.

Despite El Niño's outsize influence, scientists note there's a chance California ends up relatively dry. Nothing is guaranteed.

This article is based on reporting in the San Francisco Chronicle.