Storm Summary Number 6 for West Coast Multi-Hazard Atmospheric
River Events
NWS Weather Prediction Center College Park MD
700 PM PST Sat Jan 07 2023

...Heavy rain/snow and high winds continue across northern and
central CA...

Winter Storm Warnings are in effect for portions of the Sierra
Nevada and Klamath Mountain Ranges.

High Wind Warnings are in effect for northern California and
south-central Oregon.

Flood Watches are in effect for much of coastal California, and
the southern Sacramento Valley through San Joaquin Valley.

Wind Advisories are in effect over Coastal California, and over
the Sacramento Valley through the San Joaquin Valley.

For a detailed graphical depiction of the latest watches, warnings
and advisories, please see www.weather.gov

At 600 PM PST...Latest surface observations and RADAR depicted a
stream of moderate to heavy rainfall focusing over northern and
central California associated with the atmospheric river that
arrived Friday evening, with snowfall being confined to the higher
elevations of the Klamath and Sierra Nevada ranges. A secondary
push of moisture was depicted moving towards the northern
California coast ahead of another storm system moving eastward.
Further north, scattered light to moderate rainfall was noted over
coastal Washington.

...Selected preliminary Storm Total Snowfall in inches from 700 AM
PST Wed Jan 04 through 600 PM PST Sat Jan 07...

...CALIFORNIA...
KIRKWOOD MEADOWS 1 SSE               33.0                    
PINECREST 2 E                        32.0                    
TWIN BRIDGES 2 ESE                   26.0                    
DONNER PEAK 1 W                      22.0                    
SOUTH LAKE 1 NNE                     22.0                    
JUNE MOUNTAIN SKI BASE               18.0                    
LONE PINE 11 SW                      17.0                    
MAMMOTH MOUNTAIN SKI BASE            16.0                    
HEAVENLY SKI BASE                    12.0                    
HETCH HETCHY 10 NE                   12.0                    

...NEVADA...
MT CHARLESTON                        12.0                    
MT ROSE SKI BASE                     12.0                    

...WASHINGTON...
LEAVENWORTH 1 NNE                     7.0                    
TWISP 3 SE                            5.3                    
MAZAMA 6 ESE                          4.0                    

...Selected preliminary Storm Total Rainfall in inches from 700 AM
PST Wed Jan 04 through 600 PM PST Sat Jan 07...

...CALIFORNIA...
HEARST CASTLE 14.2 NW                8.37                    
GONZALES 15.5 SW                     7.04                    
OLD MAN MOUNTAIN                     6.57                    
HONEYDEW                             6.08                    
SIMS                                 5.85                    
FRENCH GULCH                         5.60                    
THREE PEAKS                          5.59                    
MANCHESTER                           5.45                    
LOS GATOS                            4.17                    
UKIAH MUNICIPAL APT                  4.12                    
MORAGA 2.4 NNW                       3.82                    
BURLINGAME 2.0 WSW                   3.71                    
THOUSAND OAKS 2.1 WSW                2.91                    
K6BPM SANTA BARBARA                  2.39                    
ATASCADERO 2.3 NE                    2.31                    
SACRAMENTO INTL APT                  2.18                    
SAN FRANCISCO INTL APT               1.97                    
LOS ANGELES INTL APT                 1.78                    

...OREGON...
QUAIL PRAIRE LOOKOUT                 2.88                    
LEBANON                              2.74                    
CANNIBAL MOUNTAIN                    2.57                    
CEDAR                                2.25                    

...WASHINGTON...
JEFFERSON CREEK                      5.59                    
OWL MOUNTAIN                         3.08                    
MOUNT CRAG                           3.00                    
HUCKLEBERRY RIDGE                    2.11                    
MT. BAKER - HEATHER MEADOWS          1.97                    

...Selected preliminary Peak Wind gusts in miles per hour earlier
in the event...

...CALIFORNIA...
KIRKWOOD MEADOWS 1.2 S                119                    
GRAPEVINE 3 SSE                       104                    
PULGA 2 NNW                           102                    
PABLO POINT                           101                    
YORKVILLE 5.5 NW                       95                    
CAPETOWN 6 ENE                         94                    
COBB RIDGE WEST                        91                    
ROAD TO RANCHES                        90                    
HIGH GLADE LOOKOUT                     89                    
FERNDALE 6.4 S                         88                    
MAGIC MOUNTAIN TRUCK TRL               87                    
AMERICAN HOUSE 6 NW                    84                    
AGUA DULCE 8 S                         81                    
BIG BEAR CITY 13 ESE                   72                    
MOUNTAIN GATE 3 NNE                    72                    
CRESCENT CITY 1 ESE                    69                    
JULIAN 9 S                             65                    
BLACK MOUNTAIN 7 E                     64                    


The deluge of heavy rain, snow, and strong winds with this
atmospheric river will persist over northern and central
California, with widespread rainfall of 2-4"+ expected through
Sunday. The cumulative effect of additional several inches of
rainfall after recent heavy precipitation will lead to
considerable flood impacts across much of central and northern
California, including rapid water rises, rock slides and
mudslides. Isolated major river flooding is expected through the
weekend into next week, with record river levels possible.
Numerous instances of flash flooding and debris flows are possible
over burn scar areas. Furthermore, an additional 1-3 feet of snow
is also possible during this event across the Klamath and Sierra
Nevada Ranges, which will lead to dangerous travel conditions,
especially over 4000 feet, with road closures possible. Little
reprieve from the excessively wet pattern is expected through
midweek as additional heavy rain, snow, and gusty winds will
persist with a more intense atmospheric river Monday.

The next Storm Summary will be issued by the Weather Prediction
Center at 700 AM PST. Please refer to your local National Weather
Service office for additional information on this event.

Russell/Asherman