RALEIGH, N.C. (WNCN) – The cool phase of climate pattern El Niño Southern Oscillation has developed in the tropical Pacific Ocean.
This cool phase is called La Niña, and the National Oceanic and Atmospheric Administration says it has an 87% chance of lasting through winter.
So what is the “cool phase” in the Pacific Ocean, and how will it impact our winter season?
La Niña is when cooler than normal waters form in the eastern, tropical Pacific Ocean.
The atmosphere then responds to the cooler-than-average water by creating a circulation that is driven by the difference in water temperature from the eastern and western parts of the Pacific Ocean.
This circulation is fairly strong during La Niña events, and keeps the eastern Pacific Ocean region relatively rain-free.
Also as a result of La Niña, the jet stream is more variable but often pushes north, leaving the Pacific Northwest slightly wetter and cooler than average.
It is the opposite for us in North Carolina however.
The southeast, and much of the south, remains in a warmer and drier than average pattern, with slightly wetter than average weather for portions of the Midwest, Ohio Valley, and up toward the Great Lakes.
La Niña tends to have the most impact in the winter months, from December to February.
La Niña also has an impact on hurricane season.