A long-duration atmospheric river (AR) continues to impact Northern California, bringing heavy precipitation, with two additional moisture pulses expected before it dissipates on Wednesday, February 5, 2025.
A strong atmospheric river (AR) is set to bring heavy rainfall to northern California starting Sunday, February 2, 2025, with forecasts indicating up to 380 mm (15 inches) in the Sierra Nevada, increasing the risk of flash floods and debris flows near the burn scars.
An extended period of landfalling atmospheric river (AR) activity will bring heavy precipitation to Northern and Central California starting January 31, 2025, and continuing into the following week. The event is expected to cause significant hydrologic impacts, with heavy rain, high-elevation snow, and potential flooding.
Forecast confidence in a high-impact atmospheric river (AR) event has steadily increased since January 27, 2025, and CW3E is now warning about a major AR event expected to begin this Friday, January 31 along the U.S. West Coast, and potentially continue into early next week. The most recent forecast from the NCEP Global Ensemble Forecast System (GEFS) is showing >50% probability of an AR 4 or greater over along the California coast between Santa Cruz and Mendocino Counties.
Two atmospheric rivers (ARs) are forecast to bring significant rain to the U.S. West Coast on January 30 and 31, 2025, with the potential for heavy precipitation as a second AR overtakes the first and stalls into early next week.
An atmospheric river is forecast to impact northern Alaska on Thursday, January 23, 2025, bringing in strong winds along with heavy snow through the weekend.
San Francisco experienced its first-ever Tornado Warning on Saturday morning, December 14, 2024, issued as a powerful storm system swept through the region with heavy rain and strong winds.
A series of atmospheric rivers (ARs) and mid-level shortwave troughs are forecast to deliver significant precipitation to the United States West Coast starting mid-week, potentially extending into next week. Forecasts indicate that California, Oregon, and Washington will experience varying levels of rainfall intensity, with Northern California likely at the epicenter of the heaviest activity. The first AR in the series is expected to reach California on Wednesday, December 11, 2024.
The strongest atmospheric river of the season, driven by a bomb cyclone with a central pressure of 945 hPa, ravaged the U.S. West Coast on Wednesday, November 20, 2024, bringing unprecedented rainfall, flooding, and wind damage. Northern California bore the brunt of the storm, with 543.4 mm (21.39 inches) of rain recorded in Sonoma County and widespread flooding that stranded hundreds. Meanwhile, fierce winds of up to 206 km/h (128 mph) toppled trees and left communities without power.
A powerful, rapidly intensifying cyclone wreaked havoc across the northwestern United States and parts of Canada on Wednesday, November 20, 2024, causing at least 2 deaths and leaving more than 600 000 customers (approximately 1.5 million people) in the U.S. without power. Another 140 000 customers (approximately 335 000 people) were left without power in B.C., Canada.
