FGUS76 KLOX 010133
ESFLOX
CAC037-079-083-111-020200-

Hydrologic Outlook
National Weather Service Los Angeles/Oxnard CA
533 PM PST Thu Jan 31 2019

...STRONG PACIFIC STORM SYSTEM COULD BRING SIGNIFICANT RAINFALL 
WITH FLOODING AND DEBRIS FLOW CONCERNS TO SOUTHWEST CALIFORNIA 
FRIDAY NIGHT THROUGH SATURDAY NIGHT...

.Today's storm system brought widespread rainfall of 1 to 2 inches
across Southwest California, with local amounts up to 2.50 inches
across the foothills and coastal slopes of Ventura and southern
Santa Barbara counties. A more powerful and longer duration storm
system is expected to affect Southwest California Friday night
through Saturday night. This storm will likely have a strong and
damaging south orographic wind component which will increase 
rainfall amounts and intensities across south facing foothills
and coastal slopes.

Light to moderate pre-frontal rainfall is expected to develop 
across much of the region on Friday night. The heaviest rainfall
is expected to be on Saturday, when rainfall rates between 0.50 
and 1.00 inch per hour will be common, except rates up to 1.25
inches per hour possible across south facing foothills and coastal
slopes. Additional rainfall is likely on Saturday night, possibly
heavy at times. Rainfall estimates with this storm from Friday
night through Saturday night are expected to range between 1.50
and 3.00 inches for coastal and valley areas, with between 4.00
and 7.00 inches across south facing foothills and mountains.

The threat of significant rainfall from Friday night through
Saturday night on top of the rains that fell today will likely 
bring more widespread flooding and debris flow concerns to 
Southwest California. During times of heavier rainfall, there will
be the potential for flooding of small streams and creeks, along 
with significant water flows in rivers which will increase the 
threat of swift water rescues. The Ventura River could also reach 
flood stage due to the expected heavy rains in the mountains of 
western Ventura County. Traveling across roadways will become more
treacherous as roadway flooding will likely become more 
significant and widespread, along with an increased threat of 
rockslides and mudslides in canyon roadways. For the recent burn 
areas, shallow mud and debris flows will be likely, with the the 
potential for more significant and damaging debris flows if 
rainfall rates over one inch per hour develop. A Flash Flood Watch
will likely be issued for the recent burn areas as we draw closer
to the event. 

Anyone near burn areas should be cognizant of the potential risks
and pay close attention to the latest forecasts and statements. 
If traveling across Southwest California this weekend, check the 
latest road conditions as there will likely be increased road 
closures due to flooding, rockslides, and mudslides.

$$

Gomberg/Bruno