NOAA chart shows differences in ocean surface temperature from normal.

As wildfires burn throughout California, there may be good news in the latest forecast of an exceptionally strong El Niño, which typically brings heavy winter rainfall to California.

The National Oceanographic and Atmospheric Service released data late last week showing surface temperatures in the Pacific Ocean off South America to be nearly 4 degrees Fahrenheit above normal.

“If this forecast comes true, it will place the 2015 event among the strongest El Niños,” NOAA said in its monthly report.

But an El Niño affects the weather over Southern California in a complex way, so a wet winter isn’t a certainty.

“Even a strong El Niño is not a sure-fire drought-buster for California,” noted Emily Becker, a NOAA research scientist, in her report, but it “does increase the chance of more precipitation overall during the winter, and also brings the potential for extreme rainfall. This may help alleviate the drought, but also can also lead to mudslides and flooding.”

An El Niño affects Southern California though a complex series of weather developments. The warmer Pacific waters release more heat to the atmosphere, causing air to rise and ultimately shift the North Pacific jet stream farther south and east. This typically brings more storms to the United States.

El Niño is the warm phase of a periodic warming and cooling of the Pacific off South America. This cycle is officially called the El Niño Southern Oscillation, or ENSO. The term El Niño, which is Spanish for the Christ child, arose because Peruvian fisherman noticed the warm ocean water around Christmastime.

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Chris Jennewein

Chris Jennewein is Editor & Publisher of Times of San Diego.