For many drought-weary Californians, it has become the 'Great Wet Hope.' Bill Patzert, a climatologist with NASA's Jet Propulsion Laboratory in Pasadena, has given it a less enthusiastic nickname.

"This is the Godzilla El Nino," Patzert says. "This potentially could be the El Nino of our generation."

El Nino is the term for a massive patch of warm water that appears in the Equatorial Pacific every few years, affecting weather patterns across the world. Typically, its appearance means more rain on the Pacific coast and a milder winter east of the Rockies.

"Places that are normally dry get extremely wet, and of course that would include the American west," Patzert says. "So we're kayaking down the street in Los Angeles, and they're playing golf in February in Minneapolis."

Climatologists suspected El Nino was coming. Now they're predicting it'll be even bigger than they thought.

el nino

Sea surface temperature anomalies for May 2014. Warmer colours indicate warm temperatures. (NOAA)

el nino

Sea surface temperature anomalies for May 2015. Warmer colours indicate warm temperatures, and are particularly noticeable around the equator and South America. (NOAA)

"A large El Nino like we saw in 1997 and 1982 has a big impact not only on the U.S. and Canada, but (also) all over the planet," Patzert says. "The signal that we see in the Pacific from space is actually larger than it was in August of 1997."

In 1997, a massive El Nino brought floods, mudslides and hurricanes. In California it killed 17 people and caused half a billion dollars of damage.

For a state facing critical water shortages, the idea of getting a year's-worth of precipitation in one winter sounds appealing. But Patzert says be careful what you wish for, "because El Nino comes at you like a fire hose. So you're standing there with a champagne glass trying to catch a little water, and in the meantime, the hillsides behind you are sliding into your neighbourhood."

And he says it'll take more than El Nino to erase California's drought.

"It took us many years to creep into this drought, and El Nino is no quick fix," Patzert says. "It will take us many years of above-normal rainfall to crawl out of it. So a wet winter in California, the Pacific Northwest and western Canada is really five or six big storms ... so it'll be sweet. But it's no drought-buster."

The Blob

And, Patzert says, there's a big 'if.'

"If it matures and comes to fruition."

Climatologists say don't buy that ark now … they've been wrong before. El Ninos are hard to predict, and this year, something is making it even trickier. 

The Blob

Unusually warm temperatures have been dominating three areas of the North Pacific: the Bering Sea, Gulf of Alaska and an area off Southern California. The darker the red, the higher the sea's surface temperature is above average . (NOAA)

Lurking out in the North Pacific there's a different mass of warm water, like El Nino but in a different place, known as the Blob.

"The Blob is a result of a high pressure system that has parked itself in the Gulf of Alaska for the past few years that has driven the polar jet stream north into northern Canada," Patzert says, "and then it plunged rapidly out of northern Canada into the American midwest and northeast. And so the result was hot dry winters on the west coast, and fierce winters with heavy snow pack in the midwest."

Now climatologists are wondering what will happen when these two opposite systems collide.

Patzert says it's kind of like a bad '50s horror movie: 'Godzilla' El Nino versus The Blob.

"The Blob is still there. It's very strong, very large, but it's relatively shallow," Patzert says. "So it's the Blob — which is a drought pattern — versus the El Nino, which is a drenching pattern."

What actually happens depends on where the El Nino peaks and when it fades.

It could be historic, Patzert says. Or it could be not much of anything at all.