Western Wisconsin (WQOW) - Forecasters at NOAA's Climate Prediction Center are keeping an eye on the east-central Pacific Ocean. Another El Niño event may develop over the coming months, which could result in a mild winter for western Wisconsin.
"El Niño translates from Spanish as 'little boy,'" said News 18 Meteorologist Nick Grunseth. "When El Niño occurs, the water in the eastern Pacific Ocean near the equator is warmer than average. This is usually because of lighter east winds at the equator. The warmer water near Indonesia is allowed to move east towards South America."
Grunseth says the lighter winds also put less stress on the ocean surface, which means less upwelling. In oceanography, upwelling is the rising of cooler, denser water from beneath the surface. Consistent winds will push warmer surface water a certain direction, so the cooler water from beneath moves to the surface to replace it.
El Niño events are known to modify the air pattern in favor of mild weather for the northern U.S.
"A textbook El Niño pattern involves the polar jet stream positioned north of Wisconsin," said Grunseth. "The polar jet stream is like a fence; it separates the cold air from the warm air. If the jet stream is consistently located north of us, warmer air masses will be allowed to control our weather. We may also experience drier conditions."
The southern U.S. could experience cooler and wetter conditions with the subtropical jet stream in the vicinity.
Grunseth says the forecast needs to be taken "with a grain of salt."
"Last year was a La Niña winter, which is typically cooler, and at times, a little snowier," he said. "We all know how last winter turned out - much warmer. The effects of La Niña were essentially canceled because of other factors, including the phase of the North Atlantic Oscillation. We will have to see how it plays out."
Please check the attached video link for a visual explanation from Nick on El Niño.
