Residents across Northern California and throughout the Pacific Northwest are bracing themselves for a powerful storm churning in with potential impacts of significant rainfall, strong winds, and the possibility of hazardous conditions that include power outages and flash flooding.
The Weather Prediction Center has highlighted this storm as a high-impact event, issuing alerts that include excessive rainfall risks from Tuesday through Friday. The storm is tied to the most powerful atmospheric river of the season-a term used to describe long streams of moisture that travel vast distances across the Pacific Ocean before hitting land.
The storm’s rapid intensification has led it to be categorized as a “bomb cyclone.” According to Richard Bann, a meteorologist with the National Weather Service’s Weather Prediction Center, that is due to the storm’s rapid intensification. Communities from south of Portland, Ore., to just north of the San Francisco area can expect intense weather conditions, including the potential for flooding in the lower elevations and winter storm warnings at higher elevations.
Impact and Forecasted Weather Conditions
In Northern California, flood and high wind warnings are set to take effect on Tuesday. Parts of the San Francisco Bay Area, North Coast, and Sacramento Valley could see up to 8 inches (20 centimeters) of rainfall. Tuesday is expected to remain dry, albeit cold, providing a brief period for residents to prepare before the storm fully sets in. This initial round of rain represents the first atmospheric river event of the year. The rain and snow over mountain areas are forecasted to be heavy as a result of this event.
The rain is forecasted to start at approximately 9 a.m. on Wednesday; a big Impact Day has been declared due to the expected disruption. According to Meteorologist Tamara Berg, rain will vary from light to moderate in the Sacramento Valley. The heaviest rainfall will be experienced north of Interstate 80. Snow levels will remain high, impacting areas with elevations above 6,000 feet. Depending on how the atmospheric river precisely positions, rain and snow totals could go up and down, changing how intense the impacts of the storm are.
Northern California Rainfall and Snow Projections
Northern California will see a gamut of rain and snow by the end of the week. Thursday will offer some respite in activity for some areas, but steady rainfall will likely persist further north. A second batch of rain is in store on Friday and will bring a formidable threat to the San Joaquin Valley and adjacent foothills. This day has also been marked as an Impact Day due to the potential for widespread heavy rainfall.
By Friday night, meteorologists forecast that rainfall totals will be impressive, especially over higher elevations and areas prone to heavy runoff. This could increase the threat of flash flooding and road closures. The KCRA 3 weather team has recommended that residents stay tuned for updates, as the path and strength of the storm might change, thus impacting projected impacts.