Marine Interpretation Message
Issued by NWS

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AGPN40 KWNM 061501
MIMPAC

MARINE WEATHER DISCUSSION FOR N PACIFIC OCEAN
NWS OCEAN PREDICTION CENTER WASHINGTON DC
801 AM PDT FRI MAY 6 2016

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

HIGH PRES 1030 MB W OF THE CENTRAL REGION HAS ITS RIDGE ACROSS
THE NRN WATERS. A TROUGH EXTENDS FROM INLAND LOW PRES INTO THE
CENTRAL REGION WHERE MOST OF THE CONVECTIVE CLOUDS ARE
CONCENTRATED. LIGHTNING STRIKES ARE MAINLY OVER THE CENTRAL
WATERS. MAXIMUM OBSERVED WINDS ARE OVER THE CENTRAL WATERS IN THE
GALE FORCE RANGE. THE SEAS ARE ALSO HIGHEST OVR THE CENTRAL WATERS
PEAKING AT 13 FT. SEAS RANGE BETWEEN 5 AND 12 FT ELSEWHERE. THE
NWW3 MULTI GRID WAVE MODEL IS VERY CLOSE TO THE OBSERVED SEAS
PATTERN AND IS ALSO IN GOOD AGREEMENT WITH THE ECMWFWAVE MODEL.

UPPER LEVEL RIDGE WITH LITTLE TO NO ENERGY IS OVER THE WESTERN
PARTS OF THE WATERS WHILE AN UPPER LEVEL CUT OFF LOW WITH SOME
ENERGY IS OVR THE SOUTHERN HALF OF THE FORECAST WATERS. IN THE
SHORT TERM THE ENERGY OVER THE SRN WATERS WILL PERSIST AND THAT
WILL MAINTAIN THE LOW PRES TROUGH AT THE SURFACE. THE UPPER LEVEL
RIDGE WILL ALSO PERSIST JUST W OF THE REGION AND WILL BLOCK A
BAND OF ENERGY JUST W OF IT FROM MOVING E INTO THE REGION.

THE GLOBAL MODELS HAVE CONTINUED TO INITIALIZE WELL AND THEY ARE
IN DECENT AGREEMNET ON THE FEW SYNOPTIC FEATURES IMPACTING THE
WEATHER OVER THE REGION. THE MODELS GENERALLY AGREE WELL ASLO IN
THE EXTENDDED PERIOD ON ALLOWING HIGH PRES RIDGE TO PERSIST OVR
THE ENTIRE REGION AND THAT WILL ALLOW THE WINDS TO DIMINISH TO
BELOW GALE FORCE RANGE OVER THE ENTIRE WATERS. WILL CONTINUE TO
FOLLOW GFS MODEL GUIDANCE FOR THIS FORECAST PACKAGE. IN THE SHORT
TERM HIGH PRES WILL PERSIST OVR THE WESTERN PARTS WHILE THE INLAND
TROUGH WILL WEAKEN AND ALLOW THE WINDS TO DIMINISH TO BELOW GALE
FORCE. IN THE EXTENDED PERIOD HIGH PRES WILL CONTINUE TO BUILD
INTO THE REST OF THE REGION AND KEEP A RELAXED PRES GRADIENT OVER
THE REGION.

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PREVIOUS DISCUSSION...

SUMMARY...00Z NCEP SFC ANALYSIS SHOWS A LOW PRES TROF NEAR THE
CALIFORNIA COAST...WITH A WEAK LOW CENTERED OVER THE SRN PZ6 WTRS.
ALSO A HI PRES RIDGE IS INDICATED AS MOVG NE TOWARD THE OFSHR
WTRS...WITH STRONGEST PRES GRADIENT IN THE SRN OREGON AND NRN
CALIFORNIA COASTAL AND INNER OFSHR ZONES. LATEST AVAIL ASCATB HI-
RES AND RSCAT PASSES FROM THIS EVENING AND EARLIER TONITE SHOW A
LARGE SWATH OF 30 TO 35 KT WINDS IN NORTHERLY FLOW OFF THE SRN
OREGON AND NRN CALIFORNIA COAST...WITH ANOTHER SWATH OF 20 TO 25
KT WINDS IN NW FLOW JUST W AND SW OF VANCOUVER ISLAND.

MODELS...THE SYNOPTIC PATTERN OVER THE OFSHR WTRS IS NOT EXPECTED
TO CHANGE SIGNIFICANTLY DURING THE FCST PRD...AND THE 00Z MED RNG
MDLS ARE IN VERY GUD OVERALL AGREEMNT THRU TUE NITE...SO WILL USE
THE REPRESENTATIVE 00Z GFS SOLN TO POPULATE THE WIND GRIDS OVER THE
ENTIRE FCST PRD. AM NOT PLANNING TO MAKE ANY SIGNIF CHANGES TO THE
CURRENT FCST TREND.

SEAS...ENP VERSION OF THE 00Z WAVEWATCH III MDL AND 00Z ECMWF WAM
BOTH INITIALIZED WELL OVER THE OFSHR WTRS...AND THESE MDLS ARE IN
DECENT OVERALL AGREEMNT THRU TUE NITE SO THE 00Z ENP WW3 MDL WILL
BE USED FOR THE WAVE HT GRIDS THRU THE ENTIRE FCST PRD...BUT AS
WAS DONE BEFORE WILL BOOST UP THE ENP WW3 GUIDANCE BY AT LEAST 10
PERCENT IN AREAS OF GALE FORCE WINDS.

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


.WARNINGS...PRELIMINARY.

.PZ5 WASHINGTON/OREGON WATERS...
.PZZ800...INNER WATERS FROM CAPE FLATTERY TO CAPE SHOALWATER...
     GALE SAT NIGHT.
     GALE POSSIBLE SAT NIGHT.
     GALE POSSIBLE SUN NIGHT.

.PZ6 CALIFORNIA WATERS...
.PZZ820...INNER WATERS FROM POINT ST. GEORGE TO POINT ARENA...
     GALE TODAY INTO SAT NIGHT.

$$

.FORECASTER MUSONDA/SCOVIL. OCEAN PREDICTION CENTER.



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