Moderate to heavy rain will fall steadily Friday, triggering flood alerts, plus a new Flash Flood Warning for Central San Luis Obispo County

There is a flash flood warning until 1:00 pm in Northwest and Central SLO County, including the cities of Cambria, Lake Nacimiento, San Simeon, San Luis Obispo, Atascadero, and Arroyo Grande. If in the area, move to higher ground and do not drive or walk though flood waters.

There is a flood advisory in effect until 11:15 am for west and central San Luis Obispo County, and for most of Santa Barbara County. Widespread ponding will affect roadways and intersections, and mud and rockslides are likely on canyon roads. There will also be sharp rises in small streams and normally dry arroyos.

There is a flood watch in effect for all of San Luis Obispo and Santa Barbara Counties until 4:00 am Saturday. There is special concern around northern SLO County. Excessive runoff may lead to flooding around creek or low-lying areas, and we are especially watching the Sisquoc and Salinas Rivers, with river rises peaking late Friday.

Rainfall rates will stay mostly between one half to three quarters of an inch an hour, with some periods of heavy rainfall up to an inch per hour. There is some instability, keeping the door open for thunderstorms.

We are expecting 2 to 4 inches for Santa Barbara and SLO Counties, and three quarters of an inch to 1 and a half inches in Ventura County. However, some northern and foothill areas of SLO County could receive excessive amounts, possibly totaling 6 to 12 inches. Some models even show Rocky Butte at up to 15 inches.

Temperatures are cooling a tad Friday as the storm barrels through the region. This system will be warmer than the last, however, and highs will be in the upper 50s to low 60s.

Snow will stay at 10,000 feet or higher, so it will stay out of our local mountains. There will likely be much snowmelt below 5,000 feet.

South to southwesterly winds will continue to be a factor in the storm. There is a high wind warning for the SLO and Santa Barbara mountains, the SLO interior valleys, and the Santa Lucias. Winds will be 25 to 40 mph and gusts will be up to 60 mph. There is an advisory for the rest of Santa Barbara and SLO Counties, plus the Ventura County mountains. Winds will be 20 to 35 mph, with gusts up to 50 mph. All wind alerts expire at 3:00 pm Friday.

The atmospheric river will move out of the region Saturday morning, though there may be several spotty showers following. Skies will be partly to mostly cloudy. Temperatures may rise very slightly.

Sunday is the break between storms, and temperatures will be just a tad below normal. A very weak ridge will move in and sit through Monday. Then, a fast-moving trough will approach, and there's a chance of showers the second part of the day.

Another significant storm will sweep through the area Tuesday and Wednesday, and could bring a few more inches of rain.