Southern California storm timeline: Back-to-back systems to bring rain, snow following heatwave

Weather Forecast for Thursday, April 9

The latest forecast and air quality conditions for the greater Los Angeles area, including beaches, valleys and desert regions.

LOS ANGELES - Southern California is trading its recent heatwave for a double-header of spring storms. 

Following temperatures that peaked 10 degrees above average on Wednesday, a low-pressure system is moving in to bring much-needed precipitation and cooler air to the region through early next week.

What we know:

The National Weather Service (NWS) has confirmed two storm systems will hit the region.

The first, a weaker system, will clip the region late Friday into early Saturday, primarily affecting Northern California and Oregon before reaching the south, according to the NWS.

A second, more robust cold front arrives Sunday, dropping snow levels from 7,500 feet to as low as 4,500 feet by the end of the weekend. 

PREVIOUS COVERAGE: Major spring storm to bring heavy rain, mountain snow to Southern California: Timeline

Wind gusts could reach 50 mph in the interior mountains and foothills, potentially prompting wind advisories, the NWS predicts. 

Rainfall is expected to be widespread, with common totals ranging from 0.50 to 1.50 inches, though amounts will vary locally.

What we don't know:

The NWS is monitoring whether thunderstorms will cause rain rates to hit debris flow thresholds across recent burn scars. 

Forecasters are also watching for the potential of additional rain at the end of next week. 

Timeline:

• Thursday – Friday: High clouds move in as temperatures begin a steady decline.
• Friday Afternoon – Saturday Morning: The first wave of light rain arrives, primarily affecting coastal areas.
• Sunday – Monday Morning: The second, colder storm brings heavier showers, mountain snow, and a 15–30% chance of thunderstorms.
• Tuesday: Skies are expected to clear as dry, seasonable conditions return.

What you can do:

• Adjust weekend plans: Anticipate wet conditions and potential travel delays through Sunday.
• Secure outdoor items: High winds could displace patio furniture or decorations, especially in mountain and valley areas.
• Practice road safety: "Turn around, don't drown" if you encounter flooded roadways, and allow extra travel time.
• Stay informed: Monitor local NWS updates for potential debris flow alerts or wind advisories.

What's next:

The "stronger and colder" second system is expected to linger into early Monday morning before clearing out.

A continued cool period is expected following the storm.