Long-duration storm system arrives this weekend
Mid and high-level clouds will continue to stream into the region as our next storm approaches. Saturday will start off overcast and chilly. Low temperatures will be in the 40s to low 50s. The afternoon will also be cold, with high temperatures only in the low 60s.
A cold front will bring light rain showers to the Central Coast by the early afternoon. The system will weaken as it moves south. Light scattered showers may continue here and there overnight into Sunday morning. Rain totals will generally amount to half an inch or less for this first part of the storm. Southernmost areas of the region will receive less rainfall, and Ventura County may only see a tenth of an inch.
There will be a period of moderate rain around midday on Sunday. Moderate and heavy rain will resume in a solid band structure at night. The band will be slow-moving, and rain will be consistent through Monday. Light showers will continue into at least Tuesday, when the storm will exit the state.
Between Sunday and Wednesday, rain totals will range from 2 to 4 inches in coastal areas, and from 4 to 8 inches in mountain and foothill areas. Rainfall rates will peak at 1 inch per hour. The rainfall from this storm combined with the rainfall of our most recent large storm last week creates a higher risk of flooding and landslides, particularly in mountain and canyon roadways. There is a 10 to 20 percent chance of thunderstorms, in which case rain rates could exceed 1 inch per hour. Heavier rain rates will increase the risk of flash flooding.
A flood watch is in effect for Sunday afternoon through Wednesday morning in western San Luis Obispo County, most of Santa Barbara County (except for the Cuyama Valley), and most of Ventura County (except the north mountains). Be very careful around low-lying and flood-prone areas. Excessive street flooding is possible. If you see flooded roadways, never drive through them. Turn around, don't drown! River flows will be strong. There is elevated risk around the Ventura River in particular, which is expected to exceed flood monitor stage.
This system is very unstable, and as such I cannot rule out the possibility of hail or a weak tornado. If you receive a severe weather or tornado warning alert, shelter in place until the warning has expired. Additionally, mountain travel will be hazardous at higher elevations. Several inches of snow will fall around 7,000 feet.
There will be strong southerly wind gusts, which may cause environmental damage. The combination of saturated soil from the rain and high winds raises the likelihood for downed trees. Drivers should watch for hazards in the roadway, and all should be prepared for potential power outages.
There is a high surf advisory from Saturday to Tuesday, and there should be special attention paid to Port San Luis, the Santa Barbara Harbor, and southwest-facing beaches. There is also a coastal flood advisory from early Sunday morning to early Tuesday morning. Waves will be 15 to 20 feet on the Central Coast, 6 to 10 feet on the South Coast, and 10 to 15 feet on the Ventura coast. Beach and bluff erosion is a risk, especially around areas with recent storm damage, such as Isla Vista. Stay away from the edges of bluffs and mind road closure signage.
