For Big Sur, it will arrive after 11 pm per NOAA.

A secondary stronger boundary develops tonight into tomorrow morning
and will bring more widespread coverage and higher rain rate
intensity from the Golden Gate southward. An unstable post frontal
environment given afternoon heating and atypical cold spring
temperatures aloft will encourage convective development Thursday
afternoon into night. This will spawn showers and isolated
thunderstorms and bring an additional round of hit or miss
precipitation after the primary stratiform rain band goes through
late Wednesday to midday Thursday.

Storm total rain falls will vary on the output of the convective
showers at the tail of the event, however, generally looking to
expect 1-2" in the higher terrain (highest spots 2"+), 0.50 -
1.00" for most urban valley locations, and 0.25 - 0.50" for rain
shadowed areas such as the South Bay and Salinas Valley. This
storm is strong by late April standards but more "run of the mill"
for mid-winter standards. The one key difference versus mid
winter systems will be greater differential heating tomorrow that
will lead to more widespread showers and potentially
thunderstorms.