It’s not quite a lock, but an increasingly safe bet that El Niño will develop by November or December, if not sooner.

In a bulletin released today, the National Weather Service’s Climate Prediction Center (CPC) announced the chance El Niño forms this summer is 65 percent, and the odds go up from there.

El Niño prospects reach “a peak probability of ~80% during the late fall/early winter of this year” writes Michelle L’Heureux of CPC at

As a reminder, an El Niño event is a warming of the sea surface temperatures in the tropical Pacific with ripple effects on the weather all over the world.  The specific manifestations of any given  El Niño event strongly depend on its strength (and every El Niño event is different), but the phenomenon has become associated with:

* Increased rainfall in Peru
* Drought in Australia
* Elevated rainfall in California during moderate and strong events
* Increased snowfall in the Mid-Atlantic, especially for moderate events.
* Depressed hurricane activity in the tropical Atlantic
* Increased hurricane activity in the eastern tropical Pacific
* Dry weather in the Pacific Northwest
* Cooler and wetter than average conditions in the Southeast
* Warmer than average temperatures in Alaska
* An uptick in the average global temperature

CPC’s L’Heureux says it’s too soon to say how intense this El Niño event will be, but that a strong event is on the table:

At this point, the team remains non-committal on the possible strength of El Niño preferring to watch the system for at least another month or more before trying to infer the intensity. But, could we get a super strong event? The range of possibilities implied by some models allude to such an outcome, but at this point the uncertainty is just too high.

On the flip side, L’Heureux notes the whole thing could fall apart:

…there is roughly a 2 in 10 chance at this point that this could happen. It happened in 2012 when an El Nino Watch was issued, chances became as high as 75% and El Niño never formed. Such is the nature of seasonal climate forecasting when there is enough forecast uncertainty that “busts” can and do occur.

 El Niño doesn’t necessarily portend disaster

Often, you may hear El Niño associated with weather gloom and doom (e.g. “World is unprepared for major El Niño later this year” and “Pacific braces itself for devastating El Niño as early as July” and “Why wild weather is headed your way“), but it’s a part of the natural cycle of  the atmosphere and oceans, and has a mix of positive and negative effects.

In NOAA’s list of misconceptions about El Niño, “all impacts are negative” is number one and “El Niño periods cause more disasters than normal periods” is number two. It explains:

To be sure, the impacts can wreak havoc in developing and developed countries alike, but El Niño events are also associated with reduced frequency of Atlantic hurricanes, warmer winter temperatures (and reduced heating costs) across the northern United States, and plentiful spring/summer rainfall in southeastern Brazil, central Argentina and Uruguay, which leads to above-average yields from summer crops.

It adds because El Niño  has fairly well-understood effects on global weather, it makes forecasting and preparation easier:

…compared with normal conditions, characteristic El Niño patterns enable climate scientists to produce more accurate seasonal forecasts and better predictions of extreme drought or rainfall for several regions around the globe. In turn, this improved predictability can help societies be better prepared to avoid or reduce potentially negative impacts. Ultimately, with better predictions, fewer areas with increased vulnerability may develop as disasters.