The weather has yet to be influenced this winter by a warmer Pacific Ocean and likely won’t be impacted in a major way, the National Oceanic and Atmospheric Administration reports.
Federal climatologists reduced the chances that an El Nino will form in January or February to 82 percent, down from 96 percent a month ago. If an El Nino does occur, it will be weak, according to NOAA.
“Significant global impacts are not anticipated during the remainder of the winter, even if conditions were to form,” the agency stated, in its monthly outlook on sea-surface temperatures along the equator.
The temperatures guide seasonal forecasts. For months, a warmer-than-average ocean between Ecuador and Indonesia has led climatologists to predict odds are high the Northwest will have a mild winter. In some past El Nino winters, snowpacks that supply summer irrigation have been smaller than normal. Washington’s “snow drought” in 2015 was during a strong El Nino.
This year, the warm ocean has not yet triggered the atmospheric conditions that eventually warm the northern tier of the U.S., according to NOAA. As a result, the sea-atmosphere system has remained neutral.
The sea and atmosphere are most likely to act together in late winter and early spring, according to NOAA, but by then the ocean may not be warm.
After months of warming, ocean-surface temperatures are cooling down toward neutral conditions.
The equatorial Pacific has cooled to 0.7 degree celsius above normal, down from about 1 degree above normal the month before. Climatologists classify temperatures within 0.5 degree celsius of normal as neutral.
By March, the chances an El Nino will prevail are 66 percent, down from 70 percent in last month’s outlook, NOAA forecasts.
In a 90-day period that ended Jan. 5, average temperatures in Washington, Oregon, Idaho and Northern California were slightly above normal, except for the southeast corner of Oregon and the southern end of Idaho, where temperatures were slightly below normal, according to NOAA.
The region also received slightly less precipitation than normal.
NOAA was to issue a new three-month weather outlook Jan. 17.