Less rain, but more thunder
Atmospheric river shifts to the south, but brief downpours are possible
A cutoff low-pressure system that was about 800 miles southwest of LAX on Monday afternoon is expected to bring widespread showers and a chance of thunderstorms to Southern California on Tuesday through the evening, the National Weather Service said.
A previously forecast atmospheric river component of the system carrying subtropical moisture is now expected to remain to the south, and rainfall will be associated with the cutoff lowpressure system, resulting in lower overall rainfall amounts, but a higher risk of thunderstorms.
Brief heavy downpours, probably with thunderstorms, could still cause urban flooding or minor debris flows in recent burn scars. Small hail and waterspouts over coastal waters are also a possibility with the system, although gale-force winds are no longer predicted. There’s also a risk of lightning at the beaches.
Because it is a warm storm, snow levels will be well above the 7,000-foot elevation in the local mountains.
Rain totals are expected to be about an inch to 1.5 inches for the coast and valleys of Los Angeles
County, with 1.5 inches to 3 inches in the foothills and mountains. Rates of up to 1 inch per hour are possible in fast-moving thunderstorm cells. Rain will taper off to scattered showers on Wednesday.
Another colder storm is on tap for Sunday and Monday. Rainfall is likely to be about a quarter-inch to an inch, but with a better chance of snow for the mountains.