Oregon is set for another warm winter. Despite temperatures approaching freezing in the run up to Thanksgiving, a strong El Niño is projected to create milder weather during the coming winter.
Phil Mote, professor of atmospheric sciences at Oregon State University, told Think Out Loud host Dave Miller on Wednesday that this will be the strongest El Niño since 1997. A strong El Niño was also predicted in 2014 but fizzled out during the summer. This time — much later in the season — Mote feels confident that this year's event will be particularly strong.
While El Niño can sometimes cause storms along the Pacific coast of North America, those storms usually hit south of Oregon. The Northwest usually experiences a warmer, drier climate than most winters. That's troubling for Oregon, where snowpack is roughly 30 percent of normal levels, and much of the state is still in a drought.
El Niño occurs when winds that typically blow from South America toward Australia are weaker than usual. The warm weather and moisture that normally blow towards the area northeast of Australia spread towards the east, warming large portions of the Pacific Ocean.
"When those big storms move eastward during an El Niño event, the winds that flow from west to east around the middle latitudes feel the outflow of that convection," Mote said. Those responses affect the outcome of winters in the northern hemisphere — and in the case of the Pacific Northwest, those responses mean a warmer and drier winter.
The name itself has to do with the season that El Niño typically hits. Mote says it was named by South American fishermen who noticed that the "cold, biologically productive waters were interrupted during some years during Christmastime. They referred to this warm interruption as 'Corriente del Niño, or 'current of the Christ child.'"