Marine Interpretation Message
Issued by NWS

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
AGPN40 KWNM 280217
MIMPAC

MARINE WEATHER DISCUSSION FOR N PACIFIC OCEAN
NWS OCEAN PREDICTION CENTER WASHINGTON DC
717 PM PDT WED AUG 27 2014

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

WEAK 1019 MB LOW PRES IS PASSING N OF THE WTRS THIS EVE DRAGGING A
WEAK COLD FRONT SE INTO PZ5 WTRS TNGT. THE FRONT WILL LKLY DSIPT
THU. OVERALL NO MAJOR CHANGES WILL BE MADE TO THE PREV FCST FOR
THE EVE UPDATE. THE MAIN CONCERN WILL BE THE DECAYING S SWELLS
ASSOC WITH T.S. MARIE AND THE STRENGTHENING PRES GRAD BETWEEN
HIGH PRES W OF THE WTRS AND LOW PRES JUST INLAND OVR THE WKND
INTO NEXT WK...WITH THE POSSIBILITY FOR GALES BEGINNING TO
INCREASE NEXT WK.

SEAS...SEA HTS RANGE FROM 29 FT NR T.S. MARIE TO 3 FT OVR COASTAL
WASH WTRS THIS EVE PER THE 00Z RP1 SEA STATE ANALYSIS. HIGHER
SWELLS ASSOC WITH MARIE WILL PERSIST TNGT...AND SLOWLY DECAY THU
INTO FRI. OVRALL...NO MAJOR CHANGES WILL BE NEEDED FOR THE EVE
UPDATE.

-----------------------------------------------------------------
PREVIOUS DISCUSSION...

OVER THE SHORT TERM...THE DIFFERENCES BTWN THE 12Z MDLS ARE
NEGLIGIBLE THRU FRI NITE. THE MDLS REMAIN IN GOOD AGRMT THAT A
WEAK COLD FRONT WL DRIFT SE ACRS THE PZ5 WTRS TONITE INTO THU WHL
GRADLY WASHING OUT. THEN THE NEXT SIG WX FEATURE WL BE ANOTHER
WEAK FRONT AND/OR SFC TROF FCST TO PUSH INTO THE PZ5 WTRS LATE
FRI/FRI NITE. THESE FROPAS WL SUPPRESS THE STRENGTH OF THE HIGH
PRES RIDGE W OF THE PZ5 WTRS WHICH IN TURN WL KEEP THE NNWLY
GRADIENT OFSHR REL WEAK (GNRLY IN THE 15-20 KT RANGE). BY LATE THU
INTO FRI NITE...MAINLY IN RESPONSE TO THE INLAND CA SFC TROF
STRENGTHENING SLIGHTLY...THE NNWLY GRADIENT WL STRENGTHEN SLIGHTLY
(TO 20-25 KT) ACRS THE NRN CA CSTL WTR DOMAINS. SO WITH THE 12Z
MDLS BEING SMLR...BLV THE 12Z GFS 10M BL WINDS LOOK REPRESENTATIVE
AND AS A RESULT WL USE THEM TO POPULATE OUR SHORT TERM WIND GRIDS
THRU FRI NITE. SO SINCE THE 00Z GFS 10M WINDS WERE PREVLY USED NO
MAJOR SHORT TERM CHANGES ARE PLANNED FOR THE NEXT OFSHR FCST
PACKAGE.

IN THE LONG RANGE...THE 12Z GLOBAL MDLS AGAIN ARE IN OVERALL
AGRMT THAT A HIGH PRES RIDGE WL SLOWLY BUILD INTO THE PZ5 WTRS
SAT/SUN AND THEN PERSIST THRU MON NITE...WHL AT THE SAME TIME FCST
THE INLD LOW PRES TROF TO GRADLY STRENGTHEN. AS A RESULT A GRADLY
STRENGTHENING NNWLY GRADIENT IS FCST TO VARYING DEGREES BY THE 12Z
MDLS TO DVLP THRUT THE CNTRL/NRN PZ6 AND SE MOST PZ5 WTRS THRU MON
NITE. IN FACT BY LATE SUN INTO MON NITE THE 12Z GFS FCSTS GALE
FORCE 30M BL WINDS TO DVLP IN THE CSTL WTR DOMAINS NEAR PT ST
GEORGE. FOR NOW WITH THE 12Z UKMET/ECMWF FCSTG SLIGHTLY WEAKER
NNWLY GRADIENTS WL HOLD OFF ON FCSTG ANY PSBL GALES IN THE OFSHR
WTRS THEN. SO FOR OUR LONG RANGE GRIDS PLAN ON USING A 80/20 BLEND
OF THE 12Z GFS 30M BL AND 12Z ECMWF BL WINDS...MAINLY TO TAP DOWN
THE 12Z GFS BL WINDS IN DEFERENCE TO THE WEAKER 12Z UKMET/ECMWF
SOLUTIONS.

.SEAS...BOTH THE 12Z WAVEWATCH III AND 12Z ECMWF WAM HV BOTH
INITIALIZED THE LONG PERIOD SLY SWELL FROM HURCN MARIE PASSING TO
THE S RSNBLY WELL. WITH THE DIFFERENCES BTWN THE TWO MDLS NOT
EXCEEDING 1-2 FT ON AVERAGE THRU MON NITE...PLAN ON USING A 50/50
BLEND OF THE TWO MDLS THRU MON NITE.

.EXTRATROPICAL STORM SURGE GUIDANCE...N/A.


.WARNINGS...PRELIMINARY.

.PZ5 WASHINGTON/OREGON WATERS...
     NONE.

.PZ6 CALIFORNIA WATERS...
     NONE.

$$

.FORECASTER MILLS/VUKITS. OCEAN PREDICTION CENTER.



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.