All times are local.
Saturday: Tropical storm conditions spread northward across the Baja California. Rainfall begins north of the U.S.-Mexico border in California. The storm is expected to begin weakening.
Saturday evening and overnight: This is the earliest probable landfall along the Baja California peninsula, and hurricane conditions are probable along the west coast of Mexico. The storm will continue to rapidly weaken.
Sunday morning: Tropical-storm-force winds could begin to affect Southern California. Landfall is possible at any time if it has not occurred yet. However, forecasters said, the exact path and landfall are of little overall importance since strong winds and heavy rainfall will extend far from the center of the storm.
Sunday afternoon: Tropical-force winds are expected to spread across Southern California as the most torrential rain begins soaking the region. If the storm has not yet reached land, a first and even second landfall may be possible. Flash flooding, landslides, mudslides and debris flows over burn scars left by wildfires are expected, forecasters said.
Sunday evening and overnight: The significant rain continues overnight, with rainfall totals increasing to remarkable levels in the mountains and the desert. Some locations in this arid region are slated to get one to two years’ worth of rain in a day, forecasters with the Weather Prediction Center said.
Monday: Dangerous conditions continue as the storm rapidly moves northward, but conditions slowly improve through the day, beginning in the south.