Marine Interpretation Message
Issued by NWS

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000
AGNT40 KWNM 210158
MIMATN

MARINE WEATHER DISCUSSION FOR N ATLANTIC OCEAN
NWS OCEAN PREDICTION CENTER WASHINGTON DC
958 PM EDT SUN APR 20 2014

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

ATTM I PLAN ON ONLY MAKING MINOR CHANGES TO UPCOMING PKG...EXPECT
GALE CONDITIONS TO SLOWLY DIMINISH OVER NEXT 12 HRS AS LOW CENTER
PULLS AWAY FROM CST AND WEAKENS.

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

OVER THE SHORT TERM...THO THE 12Z MDLS CONT TO DIFFER SMWHT IN
THEIR FCST TRACKS FOR THE SFC LOW NOW INVOF 32N76W THEY FCST
SMLR ASCD FCST GRADIENTS. OVERALL WL FAVOR THE 12Z GFS FCST
GRADIENTS ASCD WITH THIS LOW AND ITS 30M BL WINDS...WITH SM
MODIFICATIONS IN DEFERENCE TO THE 12Z UKMET/ECMWF. PER THIS
SOLUTION...WITH A REL HIGH FCST CONFIDENCE LEVEL...WL CONFINE
THE GALES ASCD WITH THIS SYSTEM TO THE CP HAT TO CP FEAR WTRS BY
MON MORNING...THEN FCST WINDS BCMG SUBGALE THRUT BY MON
AFTERNOON. SO DO NOT PLAN ON MAKING ANY MAJOR CHNGS TO THE PREV
NT2 FCST RGRDG THIS SYSTEM NOR ELSWHR THRU THE SHORT TERM.

IN THE LONG RANGE...THE FOCUS SHIFTS FURTHER N AS A NRN STREAM
UPR TROF IS FCST BY ALL OF THE 12Z MDLS TO DIG INTO THE NE CONUS
WED...GAIN NEGATIVE TILT AS ITS MOVES OFSHR ACRS THE NRN WTRS
WED NITE...THEN CLOSES OFF INTO A CLOSED UPR LOW THU/THU NITE
THAT DRIFTS E OF THE OFSHR WTRS. AT THE SFC...VS ITS PREV
RESPECTIVE RUNS...THE 12Z GFS REMAINS CONSISTENT IN FCSTG AN
ASCD SFC LOW TO MOVE INTO THE GULF OF MAINE TUE NITE...THEN
DRIFT E OF THE NT1 WTRS LATE WED INTO THU WHL SLOWLY
INTENSIFYING. THO THEY DIFFER IN HOW THEY FCST THEIR SFC LOWS TO
TRACK OFSHR BY THU MORNING THE 12Z GEM/UKMET (THE 12Z GEM MORESO
THAN THE 12Z UKMET) FCST SMLRLY STRONG NNWLY GRADIENTS VS THE
12Z GFS TO DVLP THRUT THE NT1 AND NRN/CNTRL NT2 WTRS. THE 12Z
ECMWF THO FCSTS A TRACK VERY SMLR TO THE 12Z GFS. SINCE THE 12Z
GEFS MEAN PROVIDES SUPPORT...AND SINCE ITS IN LINE WITH THE
LATEST WPC MEDIUM RANGE GUIDANCE AND THE 12Z ECMWF...WL FAVOR
THE 12Z GFS SOLUTION FOR THIS SYSTEM. FOR TUE/TUE NITE WL FAVOR
THE 12Z GFS 10M BL WINDS AND THEN ON WED THRU THU NITE WL FAVOR
THE 12Z GFS 30M BL WINDS IN THE COLD AIR ADVECTION BEHIND THE
SYSTEM. THEREFORE WL CONT TO FCST PSBL GALES TO DVLP ACRS THE
NT1 AND NE NT2 WTRS WED NITE INTO THU NIGHT.

SEAS...AN EARLIER 1041Z ALTIMETER PASS SHOWED SEAS UP TO 19 FT
IN THE GULF STREAM JUST OFF CP HATTERAS WHICH IS SPRTD BY THE
18Z OBS FM BUOY 41025 RPRTG 18 FT. THE 12Z WAVEWATCH III HAS
INITIALIZED THESE SEAS RSNBLY WELL AND OVERALL WL FAVOR ITS FCST
SEAS OVER THE SHORT TERM BUT WL LIKELY ADJUST THEM UPWARD BY
10-15 PERCENT INVOF THE GULF STREAM. THEN IN THE LONG RANGE WL
LKLY USE A 50/50 BLEND OF THE 12Z WAVEWATCH III AND 12Z ECMWF
WAM AS WAS DONE PREVLY.

EXTRATROPICAL STORM SURGE GUIDANCE...IN THE NNELY GRADIENT OFF
THE SE COAST THE 12Z ESTOFS FCSTS A SLIGHTLY MR SIG POSTIVE
SURGE THAN THE 12Z ETSS THRU MON WHICH LOOK REASONABLE.
OTHERWISE THE TWO MDLS ARE SMLR.



.WARNINGS...PRELIMINARY. ANY CHANGES WILL BE COORDINATED THROUGH
AWIPS 12 PLANET CHAT OR BY TELEPHONE:

.NT1 NEW ENGLAND WATERS...
.ANZ800...GULF OF MAINE...
     GALE POSSIBLE WED NIGHT INTO THU.
.ANZ805...GEORGES BANK EAST OF 68W...
     GALE POSSIBLE WED NIGHT INTO THU.
.ANZ900...GEORGES BANK WEST OF 68W...
     GALE POSSIBLE WED NIGHT INTO THU NIGHT.
.ANZ810...SOUTH OF NEW ENGLAND...
     GALE POSSIBLE WED NIGHT INTO THU.

.NT2 MID ATLC WATERS...
.ANZ915...HUDSON CANYON TO THE GREAT SOUTH CHANNEL...
     GALE POSSIBLE WED NIGHT INTO THU.
.ANZ920...BALTIMORE CANYON TO THE GREAT SOUTH CHANNEL...
     GALE POSSIBLE THU.
.ANZ905...THE GREAT SOUTH CHANNEL TO THE HAGUE LINE...
     GALE POSSIBLE WED NIGHT INTO THU NIGHT.
.ANZ910...EAST OF THE GREAT SOUTH CHANNEL AND SOUTH OF 39N...
     GALE POSSIBLE WED NIGHT INTO THU NIGHT.
.ANZ828...INNER WATERS FROM CAPE CHARLES LIGHT TO CURRITUCK BEACH LIGHT...
     GALE TONIGHT.
.ANZ925...OUTER WATERS FROM BALTIMORE CANYON TO HATTERAS CANYON...
     GALE TONIGHT.
.ANZ830...INNER WATERS FROM CURRITUCK BEACH LIGHT TO CAPE HATTERAS...
     GALE TONIGHT.
.ANZ833...INNER WATERS FROM CAPE HATTERAS TO CAPE FEAR...
     GALE TONIGHT.
.ANZ835...INNER WATERS FROM CAPE FEAR TO 31N...
     GALE TONIGHT.

$$

.FORECASTER SHAW/VUKITS. OCEAN PREDICTION CENTER.


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