National Weather Service reports and local meteorological data

Bomb Cyclone to Bring Category 5 Atmospheric River, Up to 24 Inches of Rain to Northern California

Nov 18, 2024, 10:06 AM

A powerful Pacific storm system, including a rapidly intensifying bomb cyclone starting Tuesday, is set to impact the West Coast this week, bringing heavy rainfall, strong winds, and significant mountain snow to parts of Northern California, Oregon, Washington, and British Columbia. The storm's central pressure is expected to drop more than 60 millibars in 24 hours to around 940 millibars, a bombogenesis equivalent to a Category 4 hurricane, potentially challenging for the deepest cyclone on record in the region. Meteorologists warn of a Category 5 atmospheric river, known as the 'Pineapple Express,' which could deliver up to 24 inches of rain, particularly in mountainous regions of Northern California, with the North Bay expected to be hardest hit. The system will also produce hurricane-force winds along the Washington coast and Vancouver Island, leading to power outages and ferry cancellations. Wave heights up to 70 feet are anticipated offshore. The National Weather Service and other agencies are cautioning residents to prepare for significant flooding, heavy snow in the mountains, gusty winds, and widespread travel disruptions during this first major storm of the season.