STORM SUMMARY NUMBER 3 FOR WEST COAST ATMOSPHERIC RIVER AND HEAVY
RAIN
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
200 AM PDT SAT APR 07 2018

...HEAVY RAIN IS FALLING ACROSS NORTHERN CALIFORNIA AS AN
ATMOSPHERIC RIVER PROVIDES RECORD-BREAKING MOISTURE... 

FLOOD WATCHES ARE IN EFFECT FOR MUCH OF NORTHERN AND CENTRAL
CALIFORNIA...PORTIONS OF SOUTHWESTERN OREGON...AND PORTIONS OF
IDAHO.

HIGH WIND WARNINGS ARE IN EFFECT FOR PORTIONS OF OREGON AND
WASHINGTON...NORTHERN CALIFORNIA AND NORTHERN NEVADA.

FOR A DETAILED GRAPHICAL DEPICTION OF THE LATEST
WATCHES...WARNINGS AND ADVISORIES...PLEASE SEE WWW.WEATHER.GOV

AT 100 AM PDT...A SURFACE LOW WITH A CENTRAL PRESSURE OF 972
MB...28.70 INCHES...WAS CENTERED APPROXIMATELY 450 MILES WEST OF
THE OREGON/WASHINGTON COAST AND MOVING NORTHEASTWARD. AHEAD OF THE
LOW PRESSURE SYSTEM A BROAD ATMOSPHERIC RIVER WAS PROVIDING HIGH
TO RECORD-BREAKING AMOUNTS OF MOISTURE TO CALIFORNIA AND SOUTHERN
OREGON. NATIONAL WEATHER SERVICE DOPPLER RADARS AND SURFACE
OBSERVATIONS INDICATED THAT MODERATE TO HEAVY RAIN WAS FALLING
ACROSS MUCH OF CENTRAL AND NORTHERN CALIFORNIA. LIGHT TO MODERATE
RAIN WAS FALLING ACROSS MUCH OF OREGON. 

...SELECTED PRELIMINARY STORM TOTAL RAINFALL IN INCHES FROM 100 AM
PDT THU APR 05 THROUGH 100 AM PDT SAT APR 07...

...CALIFORNIA...
OCCIDENTAL 1 W                        6.43                    
MIDDLE PEAK RAWS                      5.79                    
MILL VALLEY 2 W                       5.69                    
VENADO 7 NNW GUERNEVILLE              5.04                    
GUALALA                               4.69                    
COMPTCHE 9 W                          4.28                    
DILLON BEACH                          4.22                    
LEGGETT 1 NW                          4.04                    
ROCKPORT 3 N                          4.00                    
WHITEHORN 2 WNW                       3.88                    
BLUE CANYON/NYACK ARPT                3.34                    
YOUNTVILLE 3 WSW                      3.04                    
SHELTER COVE 1 WNW                    3.00                    
SANTA ROSA/SONOMA CO. ARPT            2.98                    
UKIAH MUNI ARPT                       2.95                    
SAN FRANCISCO 1 SW                    2.93                    
OAKLAND 3 NE                          2.54                    
REDDING MUNI ARPT                     2.49                    
SACRAMENTO METRO ARPT                 1.27                    

...SELECTED PEAK WIND GUSTS IN MILES PER HOUR EARLIER IN THE
EVENT...

...CALIFORNIA...
BURNS CANYON                          62                    
WHITEWATER RAWS 2 N                   60                    
MOJAVE ARPT                           51                    


THE ATMOSPHERIC RIVER WILL CONTINUE TO SPREAD COPIOUS AMOUNTS OF
MOISTURE ONSHORE...PRODUCING HEAVY RAINFALL ALONG MUCH OF THE WEST
COAST TODAY. BY THIS AFTERNOON THE SURFACE LOW WILL APPROACH
BRITISH COLUMBIA WHILE THE COLD FRONT SWEEPS INLAND ACROSS THE
WEST COAST STATES...CUTTING OFF THE INFLOW OF DEEP MOISTURE INTO
THE WEST COAST. WHILE THE HEAVIEST RAINFALL RATES SHOULD BEGIN TO
WIND DOWN LATE SATURDAY...ONSHORE FLOW IN THE WAKE OF THE COLD
FRONT WILL KEEP SHOWERS IN PLACE INTO SUNDAY ACROSS THE PACIFIC
NORTHWEST. ADDITIONAL RAINFALL AMOUNTS OF 2 TO 4 INCHES ARE
POSSIBLE THROUGH SUNDAY FROM WESTERN WASHINGTON AND OREGON SOUTH
TO CENTRAL CALIFORNIA...ESPECIALLY AT THE HIGHER ELEVATIONS WHERE
OROGRAPHIC LIFT WILL ENHANCE PRECIPITATION RATES. UP TO 1 INCH OF
ADDITIONAL RAINFALL IS EXPECTED AT LOWER ELEVATION LOCATIONS.

THE NEXT STORM SUMMARY WILL BE ISSUED BY THE WEATHER PREDICTION
CENTER AT 800 AM PDT. PLEASE REFER TO YOUR LOCAL NATIONAL WEATHER
SERVICE OFFICE FOR ADDITIONAL INFORMATION ON THIS EVENT.

RYAN