By Dinah Voyles Pulver and Janet Loehrke, USA TODAY

Featuring quotes by Michael McPhaden

Sea surface temperatures just hit a record high in a 2.4-million square mile region of the deep Pacific Ocean known as Niño 3.4, the key area scientists are tracking to measure the rapidly strengthening El Niño.

The daily average temperature – 85.73 degrees – on Sept. 29 was higher than at any other time on record in the region, according to preliminary data from the National Oceanic and Atmospheric Administration. It continued to climb the next day.

The temperature is about as warm as the ocean off Miami Beach and San Juan, Puerto Rico this week and warmer than the water off St. Petersburg, Florida, and Galveston, Texas.

“We are seeing a perfect storm of climate change and a super El Niño that is maturing so fast,” Ben Kirtman, dean of the University of Miami Rosenstiel School of Marine, Atmospheric and Earth Science, told USA TODAY on Sept. 30. Sea surface temperatures in the region are still climbing and could continue into November, according to Kirtman.

NOAA emphasizes the Sept. 29 number is preliminary and could change when additional data from ships, buoys and other sources is integrated. However, water temperatures at buoys along a 1,000-mile swath of the 140th meridian on Sept. 30 ranged from 83.8 degrees to 87.8 degrees, according to data provided by NOAA’s National Data Buoy Center.

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Experts watching evaporation

How much warmer could water temperatures reach in the area? “That’s an interesting question,” Michael McPhaden, a researcher at the University of Washington, told USA TODAY recently. He has studied El Niño for nearly 50 years.

Previously the thinking was the warmest average sea surface temperatures could reach was around 86 degrees (30 C), McPhaden said. “That’s because at that point, it’s likely that evaporation might begin to cool the water,” he said. “The warmer it gets, the more you evaporate.”

Now scientists aren’t so sure. In a changing climate, he said the maximum possible temperature might increase over time.

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