Marine Interpretation Message
Issued by NWS

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000
AGNT40 KWNM 251354
MIMATN

MARINE WEATHER DISCUSSION FOR N ATLANTIC OCEAN
NWS OCEAN PREDICTION CENTER WASHINGTON DC
954 AM EDT SAT APR 25 2015

.FORECAST DISCUSSION: MAJOR FEATURES/WINDS/SEAS/SIGNIFICANT
.WEATHER FOR THE NORTH ATLANTIC OCEAN W OF 50W FROM 30N TO 50N.


LIGHT WINDS AND RELITIVELY QUIET CONDS PREVAIL THIS MRNG AS HIGH
PRES OVR THE FAR SRN WATERS CONTS TO SLOWLY DRIFT ESE. A WEAK
STNRY FRONT EXTENDS OFFSHORE OVR HATTERAS CANYON. S OF THE
FRONT...WINDS ARE LGT S TO W...WITH MAINLY LGT NW WINDS N OF THE
FRONT. SEAS ARE SLOWLY DCRSNG...WITH HIGHEST SEAS NR 12 FT NR 38N
68W. CURRENT FCST LOOKS GOOD AND DO NOT EXPECT TO MAKE ANY SIG
CHANGES TO THE FCST FOR THE UPDATE.

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

OVER THE SHORT TERM...THE NEW 00Z MDLS ARE IN RSNBLY GOOD AGRMT
THAT A DVLPG SFC LOW WL RACE E INVOF 35N TONITE/EARLY SAT...FLWD
BY ANOTHER DVLG SFC LOW FWLG A SMLR TRACK LATE SAT INTO SAT NIGHT.
SMLR TO ITS PREV RESPECTIVE RUNS...THE 00Z GFS IS SLIGHTLY FASTER
THAN THE OTHER 00Z MDLS WITH THESE LOWS. THE 00Z GEFS MEAN ALSO
INDICATES THAT THE 00Z GFS IS LKLY SLIGHTLY TOO FAST. IN RGRDS TO
THE FCST GRADIENTS ASCD WITH THESE LOWS...OVERALL BELIEVE THE 00Z
GFS SOLUTION LOOKS REPRESENTATIVE. THEREFORE WL POPULATE OUR SHORT
TERM WIND FCST GRIDS WITH THE 00Z GFS 10M BL WINDS FOR TODAY INTO
SUN...THEN WL TRANSITION TO THE 00Z GFS 30M BL WINDS FOR LATE
SUN/SUN NITE ALL TIME SHIFTED 3 HRS SLOWER IN DEFERENCE TO THE
OTHER MDLS. PER THESE FCST WINDS WL NOW LIMIT ANY ASCD GALES TO
THE SW GRADIENT INADVOF THE LEAD SFC LOW ACRS THE OUTER SRN NT2
WTRS TONITE INTO EARLY SUN. SO WL BE MAKING SM SIG CHNGS TO THE
PREV NT2 FCST.

IN THE LONG RANGE...THO THEY DIFFER IN RGRDS TO THEIR EXACT FCST
TRACKS...THE 00Z GLOBAL MDLS TO AT TIMES SIGLY DIFFERENT DEGREES
ALL FCST A SERIES OF DVLPG SFC LOWS TO DUMBBELL AROUND EACH OTHER
E OF THE OFSHR WTRS MON INTO EARLY WED WITH A STRONG NLY GRADIENT
DVLPG THRUT MUCH OF THE OFSHR WTRS. TO BETTER ACCOUNT FOR THE
UNSEASONABLY STRONG NEGATIVE STATIC STABILITIES FCST IN THIS
GRADIENT...WL CONT TO POPULATE WITH THE 00Z GFS 30M BL
WINDS...WHICH ARE SPRTD BY THE 00Z UKMET/ECMWF...FOR MON THRU WED.
SO PER THESE WINDS FOR NOW WL CONT LIMIT THE PSBL GALES IN THIS
GRADIENT TO THE OUTER CNTRL/NRN NT2 WTRS MON NITE INTO TUE NITE.

THEN FURTHER OUT IN THE LONG RANGE...WED/WED NITE THE DISPARITY
BTWN THE 00Z MDLS CONTS AS THEY DIFFER SIGLY IN RGRDS TO A SRN
STREAM DVLPG SFC LOW MOVG OFSHR INTO THE SRN NT2 WTRS. IN RGRDS TO
THE FCST TRACK OF THIS SYSTEM THE 00Z GFS HAS FLIP-FLOPPED BACK TO
A MR PROGRESSIVE TRACK WHICH IS NOW MR SMLR TO THE 00Z GEM/ECMWF
TRACKS. THE 00Z UKMET LOOKS TOO PROGRESSIVE WITH THIS SYSTEM. IN
RGRDS TO THE FCST STRENGTH OF THIS SYSTEM FOR NOW WULD FAVOR A
COMPROMISE BTWN THE STRONG 00Z ECMWF AND WEAKER 00Z GFS/GEM
SOLUTIONS. THEREFORE TO ATTEMPT TO GET THIS COMPROMISE...WL
TRANSITION TO POPULATING WITH THE 00Z ECMWF BL WINDS FOR WED/WED
NITE...ADJUSTED 10 PERCENT LOWER TO KEEP THE ASCD WINDS SUBGALE
FOR NOW.

SEAS...WITH THE DIFFERENCES BTWN THE TWO MDLS REMAINING
MINIMAL...AND THEN TO TAP DOWN THE HIGH SEAS FCST BY THE 00Z
ECMWF WAM LATE WED/WED NITE OVER THE SRN NT2 WTRS...WL USE A 50/50
BLEND OF THE 00Z WAVEWATCH III (TIME SHIFTED 3 HRS SLOWER EARLY AS
DONE WITH THE 00Z GFS WINDS0 AND 00Z ECMWF WAM MDL THRU WED NITE.

.EXTRATROPICAL STORM SURGE GUIDANCE...THE DIFFERENCES BTWN THE
00Z ESTOFS AND 00Z ETSS MDLS REMAIN MINIMAL THRU TUE AS NO SIG
SURGES ARE FCST BY EITHER MDL.


.WARNINGS...PRELIMINARY.

.NT1 NEW ENGLAND WATERS...
.ANZ805...GEORGES BANK WEST OF 68W...
     GALE POSSIBLE TUE INTO TUE NIGHT.
.ANZ900...GEORGES BANK EAST OF 68W...
     GALE POSSIBLE TUE INTO TUE NIGHT.

.NT2 MID ATLC WATERS...
.ANZ915...HUDSON CANYON TO THE GREAT SOUTH CHANNEL...
     GALE POSSIBLE TUE INTO TUE NIGHT.
.ANZ920...BALTIMORE CANYON TO THE GREAT SOUTH CHANNEL...
     GALE POSSIBLE TUE INTO TUE NIGHT.
.ANZ905...THE GREAT SOUTH CHANNEL TO THE HAGUE LINE...
     GALE POSSIBLE TUE INTO TUE NIGHT.
.ANZ910...EAST OF THE GREAT SOUTH CHANNEL AND SOUTH OF 39N...
     GALE POSSIBLE TUE INTO TUE NIGHT.
.ANZ925...OUTER WATERS FROM BALTIMORE CANYON TO HATTERAS CANYON...
     GALE SUN.
     GALE POSSIBLE MON NIGHT INTO TUE.
.ANZ930...OUTER WATERS FROM HATTERAS CANYON TO CAPE FEAR...
     GALE SUN.

$$

.FORECASTER PROSISE/VUKITS. OCEAN PREDICTION CENTER.



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