El Nino and La Nina are climate patterns in the Pacific Ocean that can affect weather worldwide. During normal conditions in the Pacific Ocean, trade winds blow west along the equator, taking warm water from South America towards Asia. To replace that warm water, cold water rises from the depths, a process called upwelling. El Nino and La Nina are two opposing climate patterns that break these normal conditions.
During a La Niña year, winter temperatures are warmer than normal in the South and cooler than normal in the North. In a El Nino year areas in the northern U.S. and Canada are dryer and warmer than usual. But in the U.S. Gulf Coast and Southeast, these periods are wetter than usual and have increased flooding.
In a recent news release NOAA said about this winter’s forecast : “This year, El Nino is in place heading into winter for the first time in four years, driving the outlook for warmer-than-average temperatures for the northern tier of the continental United States, according to NOAA’s U.S. Winter Outlook released by the Climate Prediction Center — a division of the National Weather Service. ”
“These outlooks provide critical guidance on the upcoming season for many industries and sectors of our economy, from energy producers to commodities markets to agricultural interests to tourism,” said Sarah Kapnick, Ph.D., NOAA chief scientist. “With a strengthening El Nino and more potential climate extremes in an already record-breaking year, we’re lucky to have scientists like those at the Climate Prediction Center helping to build a Weather and Climate-Ready Nation by providing critical operational seasonal climate predictions.”
From December through February, NOAA predicts wetter-than-average conditions for northern Alaska, portions of the West, the southern Plains, Southeast, Gulf Coast and lower mid-Atlantic and drier-than-average conditions across the northern tier of the U.S., especially in the northern Rockies and High Plains and near the Great Lakes.
“An enhanced southern jet stream and associated moisture often present during strong El Nino events supports high odds for above-average precipitation for the Gulf Coast, lower Mississippi Valley and Southeast states this winter,” said Jon Gottschalck, chief of the Operational Prediction Branch of the Climate Prediction Center.
Chart courtesy of NOAA