161  
AGPN40 KWNM 221451  
MIMPAC  
 
MARINE WEATHER DISCUSSION FOR N PACIFIC OCEAN  
NWS OCEAN PREDICTION CENTER WASHINGTON DC  
751 AM PDT SAT JUL 22 2017  
   
FORECAST DISCUSSION
 
MAJOR FEATURES/WINDS/SEAS/SIGNIFICANT  
.WEATHER FOR THE NORTH PACIFIC N OF 30N AND E OF 150W.  
 
THE 12Z OPC SURFACE ANALYSIS DEPICTS AN OCCLUDED LOW NEAR THE  
GULF OF ALASKA THIS MORNING WITH ITS ASSOCIATED COLD FRONT  
EXTENDING ACROSS THE NORTHERN PZ5 WATERS. ELSEWHERE, A TYPICAL  
SUMMER PATTERN PREVAILS WITH 20 TO 25 KT NORTHERLY WINDS OVER  
MUCH OF THE CALIFORNIA OFFSHORE WATERS. THESE WINDS ARE DRIVEN BY  
THE TIGHTENED GRADIENT BETWEEN HIGH PRESSURE WEST OF THE WATERS  
AND AN INLAND TROUGH OVER CALIFORNIA.  
 
OVERALL, THE GLOBAL MODELS REMAIN IN GOOD AGREEMENT THROUGHOUT  
THE FORECAST PERIOD. STRENGTHENING HIGH PRESSURE WEST OF THE  
WATERS SUNDAY AND MONDAY WILL ENHANCE THE GRADIENT OFF THE WEST  
COAST, WITH WIND SPEEDS APPROACHING GALE FORCE OVER OUR INNER  
WATERS PRIMARILY FROM CAPE BLANCO TO CAPE MENDOCINO. THE INHERITED  
FORECAST WINDS WERE NOTICEABLY HIGHER THAN ANY OF THE 00Z/06Z  
MODEL GUIDANCE. THEREFORE, HAVE REPOPULATED THE WIND GRIDS WITH  
THE 00Z GFS 10M WINDS TO BETTER MATCH MODEL CONSENSUS AS WELL AS  
OUR NEIGHBORING COASTAL WATERS. THIS CHANGE SLIGHTLY PUSHES BACK  
THE TIMING OF THE GALE WARNINGS UNTIL AFTER 12Z/18Z SUNDAY FOR  
PZZ820/815. WILL DROP THE GALES FOR PZZ920 AS NONE OF THE  
AVAILABLE GUIDANCE SUPPORTS WINDS REACHING WARNING CRITERIA AT  
THIS TIME. WIND SPEEDS WILL GRADUALLY DIMINISH OVER THE OFFSHORE  
WATERS AFTER 12Z MONDAY AS HIGH PRESSURE SLOWLY DRIFTS SOUTHWEST  
THROUGH MIDWEEK AND THE GRADIENT RELAXES.  
 
   
SEAS
 
AVAILABLE OBSERVATIONS FOR THE 12Z SEA STATE ANALYSIS  
SUPPORTED MAX SEAS OF 9 FT OFF POINT REYES AND POINT CONCEPTION  
THIS MORNING. SINCE THE 00Z GFS WINDS WERE FAVORED THROUGH THE  
PERIOD, WILL KEEP THE INHERITED 00Z NWW3 ENP SEAS AT THIS TIME.  
 
   
EXTRATROPICAL STORM SURGE GUIDANCE
 
N/A.  
 
   
WARNINGS
 
PRELIMINARY.  
   
PZ5 WASHINGTON/OREGON WATERS
 
   
PZZ815...INNER WATERS FROM FLORENCE OR TO POINT ST. GEORGE
 
 
GALE SUNDAY INTO SUNDAY NIGHT.  
   
PZ6 CALIFORNIA WATERS
 
   
PZZ820...INNER WATERS FROM POINT ST. GEORGE TO POINT ARENA
 
 
GALE SUNDAY INTO SUNDAY NIGHT.  
 

 
 
.FORECASTER REINHART. OCEAN PREDICTION CENTER.  
 
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