Marine Interpretation Message
Issued by NWS

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AGPN40 KWNM 030320
MIMPAC

MARINE WEATHER DISCUSSION FOR N PACIFIC OCEAN
NWS OCEAN PREDICTION CENTER WASHINGTON DC
820 PM PDT WED SEP 2 2015

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

CLDY AREAS ARE CONFINED TO THE CNTRL REGION BUT THERE ARE NO
LGHTNG STRKES ASSCTD WITH THEM AND THE RADAR HAS NO INDC OF TSTMS
OVR THE REGION. AT 00Z HGH PRES 1029 MB W OF THE REGION HAS RIDGE
INTO THE WTRS WHILE A WEAK CLD FRNT LIES ACRS THE CNTRL WTRS. THE
PRES GRDNT IS SLCK AND OBSVD WINDS RANGE BETWN 10 AND 20 KT. LAST
ASCAT PASS AT 1805Z HAD 20 KT WINDS OVR THE NW PARTS. THE SEAS
RANGE BTWN 6 AND 10 FT...HGST OVR THE NRN WTRS.BOTH NWW3 MULTI
GRID WV MDL AND THE ECMWFWV AGREE WITH OBS.

MOST OF THE ERNGY IS STILL CONFINED IN AN UPPRLVL TROF TO THE N
WHILE THE TROF XTNSION S-WARD TO THE SRN WTRS HAS JUST SOME LITTLE
ENRGY NR THE CNTRL WTRS. UPPRLVL RIDGE LIES W OF THE UPPLVL TROF
AND ANOTHER UPPRLVL RIDGE CVRS MOST OF THE CONUS. THE RIDGE TO THE
W WILL SLIGTHLY STRENGTHEN AND THAT WILL FORCE THE TROF TO BE
SQUEEZED AND INITIALLY DIP DOWN INTO THE NRN WTRS...THE CORRSPNDNG
SFC FEATURE WILL BE A LOW MOVING ACRS THE ERN PARTS OF THE REGION.
THE ERNRY WILL SHIFT INLAND AND ALLOW THE INLAND TROF TO
STRENGTHEN AND THAT WIL FORCE A SLIGHT TIGTENING OF THE PRES GRDNT
RESULTING IN ELEVATED WINDS JUST BEFORE END OF FCST PRD.

GLBL MDLS STIL IN AGRMNT IN THE SHORT TERM BUT SLIGHT DIFFS IN THE
XTNDD PRD AS MOST OF THE MDLS DO NOT SHOW ELEVATED WINDS TWD END
OF FRCST PRD. WILL SEEK MDL THAT SHUD ELEVATE WINDS NR THE END OF
FCST PRD. ALL THE MDLS AGREE ON LEVATED WINDS OVR THE ERN PARTS OF
THE CNTRL REGION TWD END OF FCST PRD XCPT ON THE STRENGTH.
GFS/NOGAPS AND CMC HAVE GALE FORCE WINDS UKMET HAS 30 KT WHILE
ECMWFHR HAS TO 25 KT. WILL USE MDL WITH HGR WINDS...GFS. IN THE
SHORT TERM HGH PRES TO THE W WILL KEEP MOVING SLOWLY E-WRD AS THE
INLAND TROF BUILDS SLOOWLY TOO. THE HGH WILL STRENGTEN IN THE
XTNDD PAS IT GETS CLSR TO THE REGON AND THAT WILL TRIGGER ELEVATED
WINDS OVR THE ERN PARTS OF THE CNTRL REGION.

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

AN AREA OF LOW PRESSURE N OF THE AREA...ANALYZED AT 1007 MB ON
THE OPC/NCEP 18Z SFC ANALYSIS...WILL MOVE SE TOWARDS THE PZ5
WATERS BEFORE MOVING INLAND AND DISSIPATING. HIGH PRESSURE WILL BUILD
E THROUGH FRIDAY...THEN REMAIN NEARLY STATIONARY W OF THE AREA
THROUGH MON NIGHT. A WEAK FRONT WILL PASS THROUGH THE NORTHERN
WATERS SAT NIGHT AND SUN. MODELS ALL AGREE ON AN AREA OF LOW
PRESSURE WILL MOVE E TOWARDS THE WATERS ON MONDAY AND MONDAY NIGHT...HOWEVER
THEY DIFFER ON TIMING AND STRENGTH OF THE LOW PRESSURE.

CHOSE THE GFS WITH SOME MODIFICATIONS VERY EARLY ON AND VERY LATE
IN THE FORECAST PERIOD TO ADJUST WINDS TOWARD THE UKMET/ECMWF.

.SEAS...SINCE THE GFS APPEARED TO BE A GOOD CHOICE...CHOSE THE
ENP WAVE MODEL WITH A FEW ADJUSTMENTS EARLY IN THE FORECAST.
INCREASED SIG WAVE HEIGHTS THROUGH TONIGHT TO MATCH OBS.

.EXTRATROPICAL STORM SURGE GUIDANCE...N/A



.WARNINGS...PRELIMINARY.

.PZ5 WASHINGTON/OREGON WATERS...
     NONE.

.PZ6 CALIFORNIA WATERS...
.PZZ820...INNER WATERS FROM POINT ST. GEORGE TO POINT ARENA...
     GALE POSSIBLE MON INTO MON NIGHT.

$$

.FORECASTER MUSONDA/SOMMERVILLE. OCEAN PREDICTION CENTER.


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