Marine Interpretation Message
Issued by NWS

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AGPN40 KWNM 282035
MIMPAC

MARINE WEATHER DISCUSSION FOR N PACIFIC OCEAN
NWS OCEAN PREDICTION CENTER WASHINGTON DC
135 PM PDT SUN AUG 28 2016

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

SHORT TERM...A 1748Z ASCAT OVERPASS INDICATED MAX WINDS NR 20 KT
OCCURRING OFF POINT CONCEPTION AND ALSO OVR NRN WASH OFF WTRS...
WITH WINDS GENERALLY 15 KT OR LESS ELSEWHERE. GALE FORCE WINDS
WERE NOTED NW OF VANCOUVER ISLAND...NR THE QUEEN CHARLOTTE
ISLANDS. THESE WINDS APPEAR TO MATCH UP QUITE WELL WITH THE 12Z
GFS 10M WINDS. OVERALL...THE 12Z GLOBAL MODELS REMAIN IN VERY
GOOD AGREEMENT OVR THE REGION INTO WED. WE WILL...THEREFORE...
CONTINUE TO POPULATE THE FCST WITH THE GFS 10M WINDS FOR THE AFTN
PACKAGE TONITE THRU EARLY WED. THIS WILL RESULT IN LITTLE CHANGE
FROM THE PREV FEW OPC FCSTS...WITH A WEAKENING COLD FRONT STILL
FCST TO MOVE SE OVR PZ5 WTRS TONITE...MON...INTO TUE AS ASSOC LOW
PRES N OF THE WTRS MOVES SLOWLY W-NW THRU EARLY MON...AND THEN
DRIFTS TOWARD THE SE LATER MON THRU THE MIDDLE OF THE WK. FURTHER
S...HIGH PRES WILL DOMINATE THE CALIF WTRS INTO MON...BEFORE THE
HIGH WEAKENS AND MERGES WITH A LARGER HIGH PRES AREA NW OF THESE
WTRS. A LOW PRES TROF WILL STRENGTHEN ALONG THE SRN AND CENTRAL
CALIF COAST MON AFTN THRU EARLY WED. THERE IS SOME POTENTIAL FOR
GALES ASSOC WITH THIS TROF MON NITE INTO WED. FOR NOW...IT
APPEARS AS IF THE BEST CHANCE FOR ANY GALES WILL BE OVR THE
CENTRAL AND SRN CALIF COASTAL WTRS AND LKLY IN GUSTS. WE WILL
KEEP MAX WINDS AT 25 KT TO OCCASIONALLY 30 KT OVR THE ADJACENT
OFF WTRS MON NITE INTO WED...OR SIMILAR TO THE PREV FEW OPC
FCSTS. CONFDC LVLS IN THE SHORT TERM PART OF THE FCST ARE ABOVE
AVERAGE.

LONG TERM...LOW PRES WILL REMAIN JUST N OF THE WTRS LATER WED INTO
THU BEFORE DISSIPATING. HIGH PRES WILL REMAIN W OF THE CALIF OFF
WTRS LATER WED THRU FRI NITE. THE CALIF COASTAL LOW PRES TROF IS
FCST TO WEAKEN LATER WED INTO FRI...BEFORE POSSIBLY STRENGTHENING
SOME LATER FRI AND FRI NITE. ANY GALES OVR THE LONG TERM PART OF
THE FCST APPEAR AS IF THEY WILL REMAIN OVR THE CALIF COASTAL
WTRS...AND STILL MAINLY IN GUSTS. THE 12Z GLOBAL MDLS ARE SIMILAR
OVR THE WTRS LATER WED THRU FRI NITE...ALTHOUGH THE 12Z GFS
APPEARS TO KEEP THE LOW N OF THE WTRS A TAD TOO FAR S AND PERHAPS
A LITTLE TOO STRONG BASED IN THE UPPER LEVEL SUPPORT OVR THE
REGION WED NITE THRU THU NITE. THEREFORE...WE WILL TRANSITION THE
AFTN FCST FROM THE 12Z GFS TOWARD THE 12Z ECMWF MDL GUID LATER
WED AND WED NITE...AND THEN REMAIN CLOSE TO THE 12Z ECMWF MDL
GUID THU THRU FRI NITE OVR THE WTRS. OVERALL...THERE WILL BE NO
MAJOR CHANGES FROM THE PREV FEW OPC FCSTS FOR THE AFTN PACKAGE.
CONFDC LVLS ARE NEAR TO ABOVE AVERAGE FOR THE LONG TERM PORTION
OF THE FCST.

.SEAS...BOTH THE 12Z ENP WWIII AND 12Z ECMWF WAM MDLS INTIALIZED
QUITE WELL OVR THE OFF WTRS PER THE LATEST OBS AND ALTIMETER
DATA. WE WILL ADJUST THE SEA HEIGHT FCST ONLY SLIGHTLY FROM THE
PREV FEW OPC FCSTS...AND RELY ON THE 12Z ENP WWIII GUIDANCE INTO
EARLY WED...TRANSITION TO TOWARD THE 12Z ECMWF WAM LATER WED INTO
WED NITE...AND THEN TO MATCH THE WINDS REMAIN CLOSER TO THE 12Z
WAM MDL GUID THEREAFTER.

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

.WARNINGS...PRELIMINARY.

.PZ5 WASHINGTON/OREGON WATERS...
     NONE.

.PZ6 CALIFORNIA WATERS...
     NONE.

$$

.FORECASTER MILLS. OCEAN PREDICTION CENTER.


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