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Calm before the storm as the next atmospheric river nears the Central Coast

Morro Bay clouds
Posted at 4:23 PM, Mar 12, 2023

Good afternoon Central Coast!

Cloudy and dry conditions will persist through the beginning of the work week, but another atmospheric river will arrive Tuesday.

This will be a potent system with much higher rainfall amounts than typical winter storms. The ground is saturated so runoff will occur more quickly than usual, resulting in faster onset of road flooding and mud and rock slides. While snow melt from the local mountains is not expected to add significantly to the runoff, rivers and streams will be quicker to rise and flooding of small streams is possible.

There is a Flood Watch in effect for San Luis Obispo County, Santa Barbara County and the Ventura County portion of the Santa Ynez Mountains from Tuesday morning through Tuesday evening. Heavy rain and excessive runoff may result in dangerous flooding of rivers, creeks, streams, and other low-lying and flood-prone locations. Rivers and creeks that may be affected include, but are not limited to, the Salinas River, Arroyo Grande Creek and Santa Rosa Creek. Extensive street flooding is likely. There may be mudslides and rockslides, especially in and near steep terrain.

Rainfall totals of 2 to 4 inches are expected in many areas, with local totals up to 6 inches in the foothills and mountains. Rainfall rates of one half inch to one inch per hour are possible during the peak of the storm.

Monitor later forecasts and be alert for possible Flood Warnings. Those living in areas prone to flooding should be prepared to take action should flooding develop.

Tonight in San Luis Obispo it will be mostly cloudy with a 20 percent chance of rain. Low temperatures will be in the upper 40s to mid 50s. Tomorrow it will be mostly cloudy with a 20 percent chance of rain. High temperatures will be in the upper 50s to mid 60s. Tomorrow night there is a slight chance of rain in the evening, then rain is likely after midnight. Low temperatures will be in the lower to mid 50s. Southeast winds of 15 to 25 mph after midnight are expected. The chance of precipitation is 70 percent.

Tonight in Santa Barbara County it will be partly cloudy except for patchy low clouds and fog with drizzle after midnight. Low temperatures will be in the mid 40s to mid 50s. Tomorrow it will be mostly cloudy except for patchy morning low clouds and fog with drizzle. High temperatures will be in the upper 50s to mid 60s. West winds of about 15 mph are expected. Tomorrow night will be mostly cloudy. There is a 40 percent chance of rain after midnight. Low temperatures will be in the mid 40s to mid 50s.