A Flood Advisory will remain across northwest San Luis Obispo County until Thursday at 5:45 a.m. Peak rain rates between 0.75-1.50" per hour. This activity could prompt minor debris flow, especially near Avila burn scar. Expect stream flooding and the potential for rocks and boulders on to roadways.
Periods of heavy rain will redevelop across San Luis Obispo County later tonight and move through the remainder of the area Thursday into early Friday. Several inches of rain are expected with flooding concerns including recent burn areas. Several feet of high elevation mountain snow is also expected, along with moderate to strong south winds. Much quieter weather expected over the weekend into Monday.
Rainfall amounts have been impressive, and the storm still has a way to go. Cambria has received more than 6", Ricky Butte in San Luis Obispo County more than 8". Some Santa Barbara County spots saw decent numbers with light steady rainfall including Santa Barbara with 1.16", Lompoc with 2.77".
An atmospheric river has stalled over San Luis Obispo County all day Wednesday and will through Thursday morning, bringing consistent moderate to heavy rain. Rain will fall at about a quarter inch to three quarters of an inch an hour at its peak. Temperatures will remain below average in the 50s.
A flash flood watch and coastal flood advisory is in effect on the coast of San Luis Obispo County until late Thursday. Roadways and creeks may flood, and there is potential for mudslides or debris flow over recent burn scars. There is concern of hazards at Port San Luis and the Avila Burn Scar.
Southerly winds will also pick up strongly with this system. There are wind advisories in effect on the Santa Barbara County Central Coast, Santa Ynez Valley, and the San Luis Obispo County valleys until 4:00 pm Thursday. There is a high wind warning in the San Luis Obispo County mountains and on the coast until 10:00 am Thursday. Gusts could reach over 65 mph.
Thursday afternoon, the atmospheric river plume will move over the South Coast, into Ventura County and southward. It will hold its shape, continuing to bring heavy rain in its path. Rain will continue in our region, but at a little lighter rate.
By Friday afternoon, the rain will turn into lighter showers. In total from Tuesday to Friday, we could see 3 to 6 inches of rain in Santa Barbara and San Luis Obispo Counties, and up to 3.5 inches in Ventura County. Mountains and foothills will see even more rainfall, and elevations above 5,000 feet will get snow. There may be up to three feet of snow above 6,000 feet.
There is a winter storm warning until Friday at 3:00 am in the Santa Barbara and Ventura County mountains. There is also a high surf advisory in effect on the Central coast with breaking waves up to 16 feet.
The weekend is looking benign weather-wise. There may be some sprinkles or drizzle at times, but nothing like the end of week storm. Temperatures will increase slightly, reaching near normal by Monday.
There is a decent chance of light rain showers Monday and Tuesday with a low pressure system.