Graphic from Andrew Freedman’s article at Climate Central.
And an alert from the National Weather Service:
… Flash Flood Watch in effect from 7 PM PST this evening through
The National Weather Service San Francisco Bay area has issued
* Flash Flood Watch for a portion of California… including the
following areas… coastal North Bay… including Point Reyes
National Seashore… North Bay interior valleys… North Bay
mountains… northern Monterey Bay… San Francisco… San
Francisco peninsula coast and Santa Cruz Mountains.
* From 7 PM PST this evening through Friday afternoon
* rain is scheduled to arrive tonight and continue through the
night and into Friday. Copious amounts are expected in higher
elevation areas… up to several inches. Given that watersheds
are saturated from the prior storm on Tuesday… some smaller
creeks may approach or overtop Banks. Valley bottom creeks in
the North Bay… particularly those in Napa and Petaluma need to
be monitored closely.
* Storm drains may be overwhelmed and culverts may become blocked
by debris… urban flooding is likely. At times… rainfall rates
may exceed guidance thresholds for producing debris flows and
slides in mountainous areas.
A Flash Flood Watch means that conditions may develop that lead
to flash flooding. Flash flooding is a very dangerous situation.
You should monitor later forecasts and be prepared to take action
should flash flood warnings be issued.