Marine Interpretation Message
Issued by NWS

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AGPN40 KWNM 190803
MIMPAC

MARINE WEATHER DISCUSSION FOR N PACIFIC OCEAN
NWS OCEAN PREDICTION CENTER WASHINGTON DC
103 AM PDT SUN APR 19 2015

.FORECAST DISCUSSION: MAJOR FEATURES/WINDS/SEAS/SIGNIFICANT
.WEATHER FOR THE NORTH PACIFIC N OF 30N AND E OF 150W.

SUMMARY...THE LATEST HI RES ASCAT AND ASCAT-B PASSES MISSED MOST
OF THE OFF WTRS LAST EVE. THE LATEST R-SCAT IS SHOWING MAX WINDS
NR 30 KT OVR THE OFF WTRS WITH ONE GALE FORCE WIND VECTOR
RETRIEVAL OVR THE COASTAL WTRS JUST W OF OREG-CALIF BORDER. WE
WILL ALLOW GALES TO EXPIRE AS WAS NOTED IN THE EVE FCST UPDATE AS
A RESULT. OTW...A PAIR OF COLD FRONTS WILL MOVE OVR THE OFF WTRS
DURING THE NEXT FEW DAYS. THE FIRST FRONT WILL ARRIVE LATE MON
OVR WASH OFF WTRS THEN WEAKEN AS IT MOVES SE INTO CALIF WTRS MON
NGT INTO TUE. THE SECOND FRONT WILL REACH WASH OFF WTRS WED
NGT...THEN TRACK SE TO OREG AND CALIF WTRS THU INTO THU NGT.
BETWEEN THESE TWO FRONTS APPEARS TO BE THE BEST CHANCE FOR GALES
OVR MAINLY ERN SECTIONS OF THE OFF WTRS...AS THE PRES GRAD
STRENGTHENS BETWEEN STRONG HIGH PRES W OF THE WTRS AND LOWER
PRESSURES NR THE COAST AND INLAND. THESE GALES WILL BECOME MOST
LKLY OVR THE INNER CENTRAL AND INNER NOCAL OFF WTRS BY TUE EVE
AND NGT...SPREADING INTO FAR SE OREG OFF WTRS WED...BEFORE MOVG
BACK S TO INNER NOCAL AND INNER CENTRAL CALIF OFF WTRS WED EVE
AND NGT. THERE WILL BE A THREAT FOR GALES OVR NE WASH OFF WTRS
FOR A TIME TUE NGT AS WELL AS HIGH PRES BUILDS E TOWARD PZ5 WTRS.
ALSO THE GALES MAY EXPAND W TO COVER FAR ERN PARTS OF ZONE 925
FOR A TIME WED EVE. THE CONFDC LVLS IN GALES IS MDT TO HIGH OVR
NRN AND CENTRAL CALIF OFF WTRS...AND MDT OVR SE OREG OFF WTRS BY
THE MIDDLE OF THE WK. CONFDC IN THE GALES OVR NE WASH OFF WTRS IS
LOW TO MDT FOR THE TUE EVE AND TUE NGT TIME FRAME.

MODELS...ONCE AGAIN THERE IS VRY GOOD MDL AGREEMENT OVR THE OFF
WTRS FOR TODAY THRU THU NGT. THE 00Z GFS HAS REMAINED QUITE
CONSISTENT...AND HAS GOOD SUPPORT FROM THE 00Z UKMET AND 00Z
ECMWF MDL GUID. FOR THE EARLY AM FCST PACKAGE WE WILL BLEND THE
30M GFS WINDS WITH THE 10M GFS WINDS OVR THE OFF WTRS THRU THU
NGT. THIS BLEND WILL TEND TO LESSEN THE OVERALL EXTENT OF THE
GALES OVR THE OFF WTRS LTR TUE THRU EARLY THU...AND KEEP HEADLINES
SIMILAR TO THE PAST FEW OPC FCSTS. IF WE WERE TO USE JUST THE 30M
GFS WINDS GALES WOULD ALSO BE NEEDED FOR MOST OF PZ5 WTRS AND
COVER EVEN THE OUTER NOCAL AND CENTRAL CALIF OFF WTRS TUE EVE
INTO WED NGT. AT THIS TIME USING THE BLEND NOTED ABV WOULD APPEAR
MORE REALISTIC BASED ON THE WX PATTERN DVLPG OVR THE REGION.

.SEAS...BOTH THE 00Z ENP WV WATCH III MDL OUTPUT AND 00Z ECMWF WAM
WV MDL OUTPUT APPEAR TO INTIALIZED A FT OR TWO ON THE LOW SIDE
OVR OREG AND CALIF OFF WTRS BASED ON THE LATEST OBS AND EARLIER
ALTIMETER DATA. WE WILL ADJ THE FCST AS NEEDED TO FIT CONDITIONS
NOTED JUST PRIOR TO FCST ISSUANCE. FOR THE EARLY AM PACKAGE WE
WILL USE A 50-50 BLEND OF THE ENP WW3 AND ECMWF WAM MDL GUID.
THIS WILL HOPEFULLY DECREASE THE ERRORS NOTED IN ANY ONE MDL THRU
THU NGT...WITH THE ECMWF WAM PERHAPS BUILDING SEAS A LITTLE TOO
HIGH IN AND NEAR THE GALE WNG AREAS BY THE MIDDLE OF THE WEEK AND
THE ENP WV WATCH III PERHAPS BEING A BIT TOO LOW WITH SEAS HTS
FCST AT THAT TIME.

.EXTRATROPICAL STORM SURGE GUIDANCE...NA

.WARNINGS...PRELIMINARY.

.PZ5 WASHINGTON/OREGON WATERS...
.PZZ800...INNER WATERS FROM CAPE FLATTERY TO CAPE SHOALWATER...
     GALE POSSIBLE TUE NIGHT.
.PZZ815...INNER WATERS FROM FLORENCE OR TO POINT ST. GEORGE...
     GALE POSSIBLE TUE NIGHT INTO WED.

.PZ6 CALIFORNIA WATERS...
.PZZ820...INNER WATERS FROM POINT ST. GEORGE TO POINT ARENA...
     GALE POSSIBLE TUE NIGHT INTO WED NIGHT.
.PZZ825...INNER WATERS FROM POINT ARENA TO PIGEON POINT...
     GALE POSSIBLE TUE NIGHT INTO WED NIGHT.
.PZZ925...OUTER WATERS FROM POINT ARENA TO PIGEON POINT...
     GALE POSSIBLE WED INTO WED NIGHT.
.PZZ830...INNER WATERS FROM PIGEON POINT TO POINT PIEDRAS BLANCAS...
     GALE POSSIBLE WED NIGHT.

$$

.FORECASTER MILLS. OCEAN PREDICTION CENTER.



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