Storm Summary Number 4 for West Coast Multi-Hazard Atmospheric
River Events
NWS Weather Prediction Center College Park MD
700 PM PST Fri Jan 06 2023

...Heavy rain/snow and high winds moving onshore as the next
Atmospheric River arrives...

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

Flood Watches are in effect for much of northern Central Valley
and southern San Joaquin Valley.

High Wind Watches are in effect for southern Oregon.

Winter Weather Advisories are in effect for portions of the
Cascades.

Wind Advisories are in effect for much of central and northern
California.

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

At 600 PM PST...The next system slated to bring heavy rain/snow
and high winds to much of California and the Pacific Northwest was
analyzed with a minimum pressure of 976 mb (28.82 in Hg), and
located about 500 miles west of Portland, OR. Latest surface
observations and RADAR indicated precipitation had moved onshore
across the Washington and northern Oregon coastline, with light to
moderate rain falling. Further south, conditions remained
relatively dry across much of central and southern California with
light to moderate precipitation falling over northern California.
Snow and mixed precipitation remained confined to the higher
elevations of the Olympic, Cascade, and Klamath mountain ranges.

...Selected preliminary Storm Total Snowfall in inches from 700 AM
PST Wed Jan 04 through 600 PM PST Fri Jan 06...

...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                    

...COLORADO...
DOUGLAS PASS                          8.0                    
HAYDEN                                6.0                    
DINOSAUR                              4.6                    

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

...UTAH...
BRIGHTON                             17.0                    
ALTA                                 10.0                    
SPRINGDELL                           10.0                    
SUMMIT PARK                           8.0                    
SUNNYSIDE                             6.0                    

...Selected preliminary Storm Total Rainfall in inches from 700 AM
PST Wed Jan 04 through 600 PM PST Fri Jan 06...

...CALIFORNIA...
OLD MAN MOUNTAIN                     6.57                    
FRENCH GULCH                         5.60                    
THREE PEAKS                          5.59                    
LOS GATOS                            4.17                    
MORAGA 2.4 NNW                       3.82                    
BURLINGAME 2.0 WSW                   3.71                    
UKIAH MUNICIPAL APT                  3.21                    
THOUSAND OAKS 2.1 WSW                2.91                    
K6BPM SANTA BARBARA                  2.39                    
ATASCADERO 2.3 NE                    2.31                    
ROHNERT PARK 0.9 SW                  2.30                    
SACRAMENTO INTL APT                  2.16                    
SAN FRANCISCO INTL APT               1.97                    
LOS ANGELES INTL APT                 1.60                    
HOPLAND 8 SSE                        1.50                    
OXNARD NWS                           1.44                    
SANTA BARBARA MUNICIPAL APT          1.20                    
REDDING MUNICIPAL APT                1.17                    

...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                    


As the next atmospheric river event arrives Friday night into
Saturday morning into northern California, conditions are expected
to deteriorate with heavy rain/snow and strong winds moving
onshore. The focus of the event will then spread further south on
Saturday as precipitation moves southward to the central portion
of the state. Widespread additional rainfall of 3-5" +, with
locally heavier amounts possible, is expected through the weekend.
The cumulative effect of an additonal 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. Minor to isolated
major river flooding is expected through the weekend into next
week, with record river levels possible. 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 5000 feet.

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/Genz