An atmospheric river has unleashed a torrential downpour across Southern California, leading to widespread flooding and prompting evacuation warnings ahead of the holiday weekend. The deluge has already brought over 4 inches of rain to parts of the region and is expected to continue into Thursday night with rainfall rates exceeding 2 inches per hour. The National Weather Service warns of flash flooding and has issued flood watches for various areas, including Los Angeles, San Diego, Santa Barbara, and Palm Springs.

Ventura County in Southern California has been severely impacted by the heavy rain, with parts of the county under evacuation warnings until noon on Friday. The Ventura County Sheriff's Office reported early morning flooding, and the city of Oxnard experienced a significant deluge, with more than 2.5 inches of rain falling in just a few hours. This rainfall event has been classified as at least a 1-in-500-year occurrence for the city.

Santa Barbara has also been affected, with roadways underwater and multiple ramps leading to Highway 101 closed due to flooding. A flash flood warning is in effect for the city, and urban flash flooding is a possibility in lower elevation areas closer to the Los Angeles basin.

The National Weather Service predicts rainfall totals of 2 to 5 inches across most of Southern California, with an additional 5 to 10 inches possible in south-facing foothills and coastal slopes. The potential for significant and life-threatening flooding, along with rock and mudslides, debris flows near burn scars, and creek flooding, remains a concern through Thursday.

The weather service has issued a moderate risk for excessive rainfall, Level 3 out of 4, for parts of Southern California, including Santa Barbara and the Los Angeles metro area. While a few rumbles of thunder are possible, storms are not expected to turn severe.

In addition to the extreme weather in Southern California, a small tornado briefly touched down in Oroville, approximately 70 miles north of Sacramento. The EF-1 tornado, which caused minor damage to trees and structures, was on the ground for just two minutes. Fortunately, no injuries or fatalities were reported. December tornadoes are relatively rare in California.

On the opposite coast, the Northeast has also been battling severe weather. Parts of the region experienced torrential rain and devastating flooding, leaving over 130,000 power customers in Maine without electricity since Monday. With temperatures plunging near or below freezing, the Maine Emergency Management Agency expresses concern for those without power, particularly due to the challenges posed by colder temperatures. Strong wind gusts continue to impact the state, potentially hindering power restoration efforts.

As Southern California continues to face the onslaught of heavy rainfall and the Northeast struggles with the aftermath of severe weather, authorities and residents remain vigilant and take necessary precautions to ensure safety.