To prepare for the spate of inclement conditions, the city of San Diego has been monitoring some 46,000 storm drains and will preemptively close flood-prone Mission Valley roads if deemed necessary.

The first significant storm of winter will drop heavy rain across much of County from roughly 9 p.m. to midnight Thursday and produce showers Friday, temporarily easing the threat of wildfires but doing comparatively little to lift precipitation to seasonal levels,

A flood watch is in effect until Thursday along the San Diego County coast, including San Diego, Carlsbad, Poway and Chula Vista.