Spring forecasts tricky as La Niña heads out
Climate troublemaker La Niña, which is partly responsible for the extreme drought now scorching the southwestern U.S. and California, is expected to fade away over the next few months, scientists said.
In its place will be the “neutral phase” of the Pacific Ocean climate pattern officially known as ENSO (El Niño-Southern Oscillation).
The climate pattern, marked by either unusually warm or cool seawater in the central Pacific Ocean, can affect weather in the U.S. and around the world. The La Niña phase is defined by colder-than-average ocean temperatures in the Pacific. It’s the opposite of El Niño.
ENSO-neutral, colloquially known as “La Nada,” is the midpoint between El Niño and La Niña and occurs when temperatures are near average in the Pacific Ocean.
Although La Niña is on the way out, it will “continue affecting temperature and precipitation across the United States during the next few months,” the Climate Prediction Center said.
“La Niña will decay and return to ENSO-neutral during the Northern Hemisphere spring 2018,” the prediction center said. “The forecast consensus also favors a transition during the spring with a continuation of ENSOneutral conditions thereafter.”
The “in between” ocean state of ENSO can be frustrating for longrange forecasters. “It’s like driving without a decent road map — it makes forecasting difficult,” said climatologist Bill Patzert of NASA’s Jet Propulsion Laboratory.
The ENSO cycle primarily affects U.S. weather in the fall, winter and spring, and less so in the summer. It can affect the Atlantic hurricane season, however, with El Niño favoring fewer storms and La Niña favoring more.
As for what all of this means for our spring weather here in the U.S., the outlook from the prediction center generally favors dry, warm weather across the southern tier of the nation, and cooler, wetter weather across the northern tier.