The odds that the winter 2026–27 El Niño will be the strongest since 1950 jumped to 83%, up from 75% in September, federal forecasters said Oct. 15.

The National Weather Service's Climate Prediction Center raised its estimate in an updated U.S. Winter Outlook covering December 2026 through February 2027. The outlook projects warmer-than-average temperatures across the Pacific Northwest, including the Tigard area.

Mid-Pacific sea-surface temperatures along the equator have climbed to 2.4 degrees Celsius above normal, Your Oregon News reported. Models predict those temperatures could reach 3 or even 3.5 degrees above normal, according to the Climate Prediction Center.

The record three-month average was 2.75 degrees above normal during November 2015 through January 2016.

For Tigard, Tualatin and Durham, the forecast sharpens a concern we reported Sept. 21: flooding along Fanno Creek. The 15-mile Tualatin River tributary receives about half its roughly 50 inches of annual precipitation in November, December and January.

The highest flow ever recorded at the U.S. Geological Survey's Durham gauge was 1,670 cubic feet per second on Dec. 3, 2007.

Ken Graham, director of NOAA's National Weather Service, said wet conditions on dry ground carry risk. "While higher chances of rain and snow may bring relief to drought-afflicted areas, too much precipitation on dry soil can fuel destructive flash floods and mudslides," Graham said in the outlook.

Oregon State Climatologist Larry O'Neill told Your Oregon News on Sept. 18 that the El Niño's record-level strength makes the outlook hard to predict. "We really don't have a good sense of what's going to happen," O'Neill said.

One complicating factor: the Pacific Decadal Oscillation (PDO) remains in a cool phase, meaning ocean water off the West Coast is cooler than normal.

During past very strong El Niños, the PDO was in a warm phase. O'Neill said on Sept. 18 that the cool phase could moderate some warming along the coast.

The NOAA outlook also noted that drought conditions could worsen in northeastern Oregon and eastern Washington, even as drought improves across the southern United States.

Tigard residents can sign up for Everbridge emergency alerts through the city. Statewide alerts are available through OR-Alert or by texting a ZIP code to 888777.

NOAA's next seasonal forecast update is scheduled for Nov. 19.