The images above show warming (red) waters in the Pacific that indicate El Nino. Use the slider in the center to move back and forth between images and note how much the warming has dissipated in recent months. (NASA/JPL)
Forecasters had been more optimistic last spring, when they saw what looked like the potential for a big honkin' El Niño, just in time for the rainy season. Typically it's only stronger El Niños that exert enough influence on the atmosphere to produce heavy rains in California, and those are relatively rare events.
"That El Niño that was really coming on like gangbusters in the spring has virtually disappeared at this point," says Patzert. "Unless we see a miraculous resurgence, any hope for an El Niño soaking this winter is pretty much in the rear-view mirror."
Patzert calls this a "classic false start" for El Niño, which he says is not that unusual.
The key, he says, is the strong trade winds that blow from the Americas toward Asia, piling up warm water toward the western side of the Pacific. When those winds abate, that warmer surface water starts sloshing back toward us.
"Unfortunately as summer showed up, those trade winds had a resurgence, and whatever we had in terms of warm water in the central and eastern Pacific had disappeared."
That doesn't necessarily mean a fourth dry winter. Patzert says other forces could work in our favor; the stubborn ridge of high pressure that parked along California's coast last winter and forced the usual Pacific storms to detour north, could just as easily give way this year. If it does, says Patzert, "We could have one wet, cold storm after another making its way down the length of California, and that would certainly be sweet."
El Niño is technically one phase of what scientists call the El Niño Southern Oscillation. It's opposite is known as La Niña, characterized by colder surface temperatures and drier times in California. Forecasters see very little likelihood of La Niña conditions in the foreseeable future.