Forecast models suggest that El Niño conditions are likely to develop during 2026, marking a shift from the ongoing weak La Niña. The transition is expected to influence jet stream patterns and temperature anomalies across the United States, Canada, and Europe, potentially reshaping rainfall distribution and winter storm activity in the Northern Hemisphere.
A powerful winter storm hit the Pacific Northwest and parts of the inland Northwest on December 17, 2025, causing widespread power outages across Washington, Oregon, and Idaho. At least 596 830 electricity customers were left without power, an impact estimated to affect approximately 1.4–1.6 million people across the region, as strong winds damaged power infrastructure and disrupted services.
Historic flooding in December 2025 placed Washington state in the middle of a statewide crisis, with impacts ongoing and damage assessments still underway as of December 17. Prolonged heavy rainfall has inundated communities, damaged levees and transportation infrastructure, and forced large-scale evacuations across multiple counties. At least one person died after driving into deep floodwaters.
High Wind Warnings have been issued across much of the western and central United States, effective from early Wednesday, December 17, 2025, through Thursday morning, December 18. Forecasts indicate a rapidly deepening low-pressure system developing east of the Canadian Rockies, producing winds of over 130 km/h (80 mph) in some areas. Power outages, tree damage, and hazardous travel conditions are expected from the Intermountain West to the Great Plains.
A levee breach along the White River prompted evacuation orders and Flash Flood Warning for the city of Pacific on December 16, 2025.
Two atmospheric rivers are forecast to bring prolonged heavy rain and mountain snow to the Pacific Northwest and northern California through December 20, 2025. The Weather Prediction Center (WPC) forecasts 100–150 mm (4–6 inches) of precipitation across western Washington and 100–200 mm (4–8 inches) across western Oregon, with locally higher totals in the Cascades and coastal ranges.
Evacuation notice and the Flash Flood warnings were lifted for King County after crews successfully contained the Green River Levee which failed near Tukwila, Washington on December 15, 2025, triggering flash floods in the area.
Freeze warnings were issued by the National Weather Service (NWS) for parts of Florida, Georgia, Alabama, Louisiana, and Texas early on December 15, 2025, lasting through December 16. Temperatures dropped as low as 21°F (−6°C) in central Louisiana and 24°F (−4°C) in northern Florida, with wind chills reaching 14°F (−10°C).
At least two people were reported dead in traffic crashes as a powerful winter storm dropped up to 20 cm (8 inches) of snow across parts of Long Island, New York, including Nassau and Suffolk counties, on December 14, 2025, creating dangerous travel conditions. Suffolk County Police reported approximately 200 vehicle collisions across the island as the storm moved through the region.
The National Weather Service (NWS) issued multiple high wind warnings and watches across the Pacific Northwest and northern Rockies on Monday, December 15, 2025, as a strong surface low-pressure system moved into the region. The alerts cover parts of Montana, Wyoming, Idaho, Washington, and Oregon, and remain in effect through Wednesday afternoon, December 17, with sustained winds of 40–70 km/h (25–45 mph) and gusts exceeding 110 km/h (70 mph) forecast in exposed and mountainous areas.
