El Niño is strengthening and it looks a lot like the strong event that occurred in 1997–98, the latest analyses from the National Oceanic and Atmospheric Administration and from NASA has confirmed.
Observations of sea surface heights and temperatures, as well as wind patterns, show surface waters cooling off in the Western Pacific and warming significantly in the tropical Eastern Pacific, according to the analysis.
"Whether El Niño gets slightly stronger or a little weaker is not statistically significant now. This baby is too big to fail," said Bill Patzert, a climatologist at NASA's Jet Propulsion Laboratory. October sea level height anomalies show that 2015 is as big or bigger in heat content than 1997. "Over North America, this winter will definitely not be normal. However, the climatic events of the past decade make 'normal' difficult to define."
The maps above show a comparison of sea surface heights in the Pacific Ocean as observed at the beginning of October in 1997 and 2015. The measurements both show averaged sea surface height anomalies. Shades of red indicate where the ocean stood higher (in tens of millimeters) than the normal sea level because warmer water expands to fill more volume. Shades of blue show where sea level and temperatures were lower than average (contraction). Normal sea-level conditions appear in white. [Photo/NASA] |
"The trade winds have been weakening again," Patzert said. "This should strengthen this El Niño." Weaker trade winds out of the eastern Pacific allow west wind bursts to push warm surface waters from the central and western Pacific toward the Americas.
In its October monthly update, scientists at NOAA's Climate Prediction Center stated: "All multi-model averages predict a peak in late fall/early winter. The forecaster consensus unanimously favors a strong El Niño. Overall, there is an approximately 95 percent chance that El Niño will continue through Northern Hemisphere winter 2015–16."
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