Storm Summary Number 1 for West Coast Atmospheric River and Wind
Event
NWS Weather Prediction Center College Park MD
700 AM PST Wed Nov 20 2024

...A strong area of low pressure over the waters of the Pacific
Northwest will bring strong winds and an accompanied atmospheric
river will bring a flooding threat... 

High Wind Warnings are active across interior mountain locations
over northern California and Oregon

A Storm Warning is active overs the waters off Oregon and
Washington.

A Blizzard Warning is active across the Cascades in Washington
State.

Winter Storm Warnings and Advisories are in effect for the
mountains in northern Califronia to Washington.

Flood watch is active along the Oregon and California Coastlines.

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

At 600 AM PST...A deep area of low pressure, surface observations
report 950 mb (28.05 in), is spinning in the Pacific to the west
of Washington State and British Columbia. An occluded front is
located over the coastlines of Washington, Oregon, and northern
California. A stationary front extends off the north California
coastline and another stationary front was located over the
northern and central California coastal region. Radar shows gusty
showers from Washington southwards to Oregon along the occluded
boundary. Snow was ongoing over interior elevation, particularly
the Cascades. Moderate to heavy rain was located over northern
California and is focused along the triple point of the frontal
boundary and strongest fetch of moisture from the Pacific where
the atmospheric river is setting up. 

...Selected preliminary Storm Total Rainfall in inches from 600 AM
PST Tue Nov 19 through 600 AM PST Wed Nov 20...

...CALIFORNIA...
COOKSIE MOUNTAIN                     2.68                    
EEL RIVER CAMP                       2.09                    

...OREGON...
CEDAR                                3.24                    
SOUTH FORK                           2.71                    
CANNIBAL MOUNTAIN                    2.28                    

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

...CALIFORNIA...
VAN BREMMER                            82                    
INDIAN WELL                            80                    
GAZELLE                                79                    
WEST WEED                              74                    
BOLMUS                                 70                    
EAST LAKE SHASTINA                     68                    
WEED AIRPORT                           67                    

...OREGON...
ACORN WOMAN PEAK                       89                    
LONG PRAIRIE                           82                    
FLYNN PRAIRIE                          80                    
YAQUINA                                73                    
FLORENCE                               67                    
CROWN POINT                            63                    
SUGARLOAF                              61                    

...WASHINGTON...
MOUNT RAINEER                          77                    
CRYSTAL MOUNTAIN                       74                    
W CAPE ELIZABETH                       72                    
KOSMOS                                 71                    
CAMANO ISLAND                          63                    
SEATAC AIRPORT                         59                    
SEATTLE                                35                    


A potentially high end impact flooding event is underway. The
latest forecast calls for the area of low pressure in the Pacific
to be nearly stationary over the next couple of days. The moisture
streaming in from the Pacific should continue over the next
several days as the synoptic set-up is relatively static in
regards to the low pressure and associated frontal boundaries. The
latest forecast calls for 12-16 inches of rainfall over northern
California and far southwest Oregon into Friday. The atmospheric
river and heavy rainfall intensity is forecast to peak on
Thursday. In the Cascades and mountains of northern California, a
heavy snow threat will unfold as several feet of accumulation are
possible. Strong winds will combine with snow to produce potential
blizzard conditions. Along the coastlines and in/near areas of
terrain, a wind threat will also be present. Wind gusts over 60
mph are possible and may create issues with downed trees and power
failures. Coastal flooding will also be a threat. 

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

Wilder