Greater San Diego could get 1.5 inches of rain from an “atmospheric river” weather system that will flow ashore Thursday night and last through Friday, when it also will leave a few inches of snow on the county’s highest mountain peaks, says the National Weather Service.
An intense cold front will tap into subtropical moisture and take on atmospheric river characteristics as it moves southeastward through the Central Coast on Wednesday into Thursday.
At this time, between 2 and 4 inches of rain is expected along the Central Coast. However, if the front stalls over a particular area, rainfall amounts will be much higher.
One week, it’s fires; the next, it’s feet upon feet of snow. In the middle of January, high winds and dry conditions sparked wildfires throughout California. Now, an atmospheric river is taking aim at the state with a huge amount of water. In the Sierra Nevada and Lake Tahoe region, forecasters are calling for between three and six feet of snow by the end of this week.
Clear out the gutters. Plan some extra time for the morning commute Wednesday. And don’t even think about heading up the hill for a few days. The biggest storm of the season is barreling down on Northern California. The Sacramento region could see up to 3 inches of rain this week – perhaps doubling the amount of rain we’ve received for the entire winter season – as an extreme storm arrives Tuesday afternoon. The cold, wet system will bring dangerous winds to the region, localized flooding and up to 80 inches of snow – yes, that’s nearly 7 feet – to the summits on Interstate 80 and Highway 50.
San Diego researchers are getting a better understanding of the storm systems that bring the region most of its rain and they are getting that information the old fashion way — from weather balloons. Last March, gray rain-filled skies seemed to dip into the ocean as a storm moved across the region.
The San Diego County Water Authority is partnering with the renowned Scripps Institution of Oceanography at UC San Diego to better predict atmospheric rivers and optimize water management before, during and after California’s ever-changing seasonal storms.
Atmospheric river storms produce 40%-60% of the West Coast’s annual precipitation and are responsible for the majority of flood damage in the region. Predicting and managing this is challenging due to unpredictable and changing snowmelt and rainfall.
To study this, Scripps’ Center for Western Weather and Water Extremes (CW3E) introduced the Water Affiliates Group, which brings together relevant science and water industry expertise to enhance reservoir operations along with California’s changing climate.
Hurricanes have the Saffir-Simpson Scale (Category 5), tornadoes have the Enhanced Fujita Scale (EF-3) but now the West Coast has a storm scale of our own with a recent introduction of a new rating system for atmospheric rivers — the causes of a vast majority of our annual autumn and winter flooding damage.
California may see a 54 percent increase in rainfall variability by the end of this century, according to new research from the lab of Assistant Professor Da Yang, a 2019 Packard Fellow and atmospheric scientist with the University of California, Davis. Writing in the journal Nature Climate Change, Yang and his co-authors predict the entire West Coast will experience greater month-to-month fluctuations in extremely dry and wet weather, especially in California. The lead author is Wenyu Zhou, a postdoctoral researcher in the Lawrence Berkeley National Laboratory where Yang has a dual appointment.
The study explores the Madden-Julian oscillation (MJO), an atmospheric phenomenon that influences rainfall in the tropics and can trigger everything from cyclones over the Indian Ocean to heatwaves, droughts and flooding in the United States.
Wild weather will bear down on the holiday season with a soaking atmospheric river for the West, drenching tropical downpours for the South and soaring temperatures in the East. For most, dreams of a white Christmas will remain just that.
On-and-off rain for the better part of a week is expected to continue Tuesday and Wednesday in the Bay Area, but a larger storm will likely swamp the region starting Thursday, officials said.
A weather system from the Northwest and coast is expected to bring rain to areas that have not been affected as much by the recent storm, such as San Jose and Redwood City, according to the National Weather Service.
