The NWS Weather Prediction Center has issued a rare High Risk (level 4/4) for excessive rainfall across Southern California from Wednesday, December 24, through the morning of Thursday, December 25. 2025.
Extremely dangerous marine conditions are developing across Northern and Central California waters this week, the National Weather Service (NWS) San Francisco Bay Area warned on Tuesday, December 23, 2025. Storm Force winds are forecast across the coastal waters with Gale Force winds extending into San Francisco and Monterey bays beginning Tuesday morning. Seas are expected to build to near 6 m (20 feet) under the strongest winds, posing life-threatening conditions for mariners.
Winter Storm Warnings are in effect across parts of California from late December 23 through December 27, 2025, as a strong atmospheric river moves inland, bringing heavy mountain snowfall and high winds.
A strong atmospheric river is forecast to impact California from December 23 to 27, 2025, bringing widespread heavy rainfall, flash flooding, and high-elevation snow. The system is expected to produce 250 to 500 mm (10–20 inches) of precipitation in parts of the Sierra Nevada and 150 to 300 mm (6–12 inches) in the Coast and Transverse Ranges. The National Weather Service has issued high-risk alerts for flash flooding across southern California and moderate winter storm impacts over the Sierra Nevada.
At least eight people have died after heavy snow, floods, and blizzards affected more than 25 provinces in Iran between December 15 and 21, 2025, according to the Iranian Red Crescent Society.
Heavy rains triggered severe flash floods in the Guci hot spring area in Central Java’s Tegal Regency on Sunday, December 21, 2025, causing widespread damage.
One person was killed and several were rescued after torrential rain from an atmospheric river caused severe flooding in Redding, northern California, on December 21–22, 2025. Rainfall totals above 100 mm (4 inches) overwhelmed storm drains, flooded roads.
A tornado touched down in a rural area near Santa Rosa del Monday, Alto Paraná Department, on December 21, 2025, amid severe thunderstorms affecting eastern Paraguay. The phenomenon was documented on video by residents, with reports of localized damage to vegetation and infrastructure but no confirmed casualties.
Three atmospheric rivers are expected to impact California between December 20 and 25, 2025, producing 250–500 mm (10–20 inches) of rain over the Sierra Nevada and 75–180 mm (3–7 inches) over southern coastal ranges. The strongest system is forecast to peak on December 23–25 with IVT values surpassing 750 kg m⁻¹ s⁻¹ and AR3–AR4 intensity.
Forecast models indicate that the Polar Vortex will strengthen in late December 2025 after a split and disrupted phase earlier in the season. The recovery is expected to influence North American and European weather in January 2026, potentially sending colder air southward while reorganizing jet stream flow.
