We haven't had a ton of weather these past two winters here in Northern California, which has meant we haven't had much rain. But that all could change as meteorological experts have officially begun an El Niño watch in the Pacific for this summer. There's still no guarantee, and there was a false alarm about a "weak" El Niño year back in 2012 which never actually developed, but signs are pointing to a warming trend in the ocean a few hundred feet below the surface.

The National Oceanic Atmospheric and Administration issued the El Niño watch today, and Kevin Trenberth, a senior scientist at the National Center for Atmospheric Research, separately told the AP that he agrees one is coming. "This could be a substantial event," he says, "and I think we're due."

An El Niño winter comes as a result of warming in the Pacific and lasts from December to April.

If you're confused about what El Niño and La Niña years tend to mean for California, you can read this partial explanation we gave during the last La Niña winter in 2010-11. Basically, in an El Niño, we can typically expect more rain and precipitation across the U.S., which could alleviate our drought problems, a milder winter in the north and northeast, and fewer Atlantic hurricanes. The last one we had was in 2009-10, but that and the previous one were pretty moderate. The last robust El Niño year with truly significant rainfall was in 1997-98, and since then we've had also had five weak, cooler La Niña years.

Elsewhere in the world, the warming from El Niño can wreak havoc, causing record-breaking high temperatures and killing crops. The '97 El Niño caused an estimated $3 billion in agricultural damage.