A new report from NOAA's Climate Prediction Center suggests changes could be on the way for weather patterns across the U.S. and the globe.
According to the report, the chance of an El Niño reemerging this year has increased. And, if the models from the report play out, that could mean fewer named storms in the 2014 Atlantic hurricane season and potential drought relief for parts of California later this year.
An El Niño cycle can occur every two to seven years, when weaker trade winds allow warmer water around the equator in the far eastern Pacific Ocean to emerge. That warmer water changes wind patterns and alters storm cycles around the globe.
(MORE: What's El Niño?)
In general, the eastern tropical Pacific ocean cycles between three phases: El Niño (warmer than average sea-surface temperatures), La Niña (cooler than average sea-surface temperatures) and a neutral phase in which sea-surface temperatures are generally near long-term averages.
Since spring 2012, the eastern Pacific ocean has been in the neutral phase, but according to the latest NOAA/CPC report, there’s now a 50 percent chance that equatorial waters in the Pacific will warm sufficiently to meet the criteria for an El Niño. As a result, NOAA's Climate Prediction Center has issued an El Niño Watch for summer 2014.
Mike Halpert, deputy director of the Climate Prediction Center, explains, “A watch simply means that conditions across the tropical Pacific are favorable for the development of El Niño during the next, roughly, three to six months.”
He noted that a watch doesn't guarantee an El Niño will occur, but the models are leaning that way.
Climate Prediction Center Model Data
CPC model data shows an uptick in sea surface temperature anomalies later in the year.
A plot of the model data listed in the report shows a marked warming trend in tropical Pacific waters by mid-summer. The average of all the models suggests a 0.5ºC temperature anomaly is probable around August. According to Halpert, that would place this El Niño event on the weak end of the Climate Prediction Center's spectrum.
“Unofficially, CPC’s own characterization is: between 0.5º and 1ºC is a weak event, between 1º and 1.5ºC is a moderate event and stronger than 1.5ºC is a strong event,” Halpert said.
Halpert said that the models used by the CPC are susceptible to a phenomenon know as the “spring barrier.” That’s when the model's deterministic ability slightly decreases in the early months of the year. While it’s able to hone in on broad changes in sea-surface temperature anomalies, Halpert said forecasts of the strength of the El Niño are much more reliable closer to the middle of the year.
If El Niño Develops, It Might be Good News
Researchers have found that instances of Atlantic tropical storms and hurricanes are usually reduced during an El Niño year. Based on the current model data, it appears that El Niño could develop near the height of the Atlantic hurricane season — potentially inhibiting some tropical development.
But Halpert said even with El Niño, strong tropical cyclones are still possible. “I always like to remind people of the 1992 hurricane season, which was an El Niño year and only featured seven named storms. But the first one was Andrew.”
Also, despite development of a weak El Niño, Hurricanes Charley, Frances, Ivan, and Jeanne raked parts of Florida during the 2004 Atlantic hurricane season.
If El Niño develops, beneficial rains could bring much-needed relief to some drought-stricken areas, most notably California.
During El Niño, winters in parts of California are sometimes wetter than normal. But, before the beneficial rains arrive, Californians would likely have to endure a grueling drought through the spring and summer.
MORE: Climate Change in NASA Satellite Images
The Ash Creek Fire seen here is one of some 27,000 fires which have destroyed nearly 2 million acres of the western U.S. since the start of 2012. Extremely dry conditions, stiff winds, unusually warm weather, and trees killed by outbreaks of pine bark beetles have provided ideal conditions for the blazes. (Credit: NASA)