Much-needed rains forecast for Southern California this weekend
Much-needed rains are forecast for Southern California this weekend as a low-pressure system impacts the state heavily affected by devastating wildfires.
GFS Total Accumulated Precipitation January 24 - 28, 2025. Image credit: TropicalTidbits
A low-pressure system is expected to slowly move down the U.S. West Coast late this week into the weekend, bringing much-needed precipitation to Southern California. This weather event follows a period of heightened fire risk in the region fueled by strong Santa Ana winds and dry conditions.
While anticipated rainfall will not be sufficient to eradicate the ongoing drought, it will aid in fire containment efforts and potentially prevent new fires from igniting.
The National Weather Service (NWS) Weather Prediction Center forecasts precipitation amounts between 20 and 50 mm (0.8 – 2 inches) across Southern California, with the highest totals expected in the Transverse Ranges.
The Ensemble Prediction System (EPS) indicates an average precipitation of about 13 mm (0.5 inches), slightly above the 7.6 mm (0.3 inches) predicted by the Global Ensemble Forecast System (GEFS) for coastal watersheds in Southern California over the next ten days.
Some EPS members suggest that certain areas, such as San Diego and San Luis Rey-Escondido, could see rainfall exceeding 5% of their annual totals.
As the system approaches, there is a possibility of thunderstorms, particularly near burn scars from previous wildfires. This raises concerns about localized heavy downpours leading to debris flows in these vulnerable areas.
Additionally, freezing levels are projected to drop to around 1.2 – 1.5 km (4 000 – 5 000 feet), which may result in snowfall at higher elevations across Southern California.
There remains some uncertainty regarding the track of the low-pressure system, which will influence how much moisture it can draw from the Pacific Ocean. Current models suggest a more inland trajectory may limit precipitation amounts further south in areas like Los Angeles and San Diego, where rainfall could be significantly less than in northern regions.
Atmospheric river activity is expected to remain quiet over the US West Coast through the end of January.
References:
1 Quick Look at the Low-Pressure System Forecast to Bring Precipitation to Southern California Updated: 22 January 2025 – CW3E – January 22, 2025
I'm a dedicated researcher, journalist, and editor at The Watchers. With over 20 years of experience in the media industry, I specialize in hard science news, focusing on extreme weather, seismic and volcanic activity, space weather, and astronomy, including near-Earth objects and planetary defense strategies. You can reach me at teo /at/ watchers.news.
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