Marine Interpretation Message
Issued by NWS

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000
AGNT40 KWNM 281328
MIMATN

MARINE WEATHER DISCUSSION FOR N ATLANTIC OCEAN
NWS OCEAN PREDICTION CENTER WASHINGTON DC
828 AM EST SUN 28 DEC 2014

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

COLD FRONT WILL REACH THE NEW ENGL COAST AND MOVE OFFSHORE THIS
AFTERNOON WITH STEADILY INCREASING SW WINDS AHEAD OF BOUNDARY.
06Z GFS WAS GENERALLY CONSISTENT WITH ITS PREVIOUS RUN THROUGH
THE SHORT TERM AND OVERALL IS ABOVE AVG MODEL AGREEMENT OVER THE
W ATLC FOR THE NEXT COUPLE DAYS. GFS/ECMWF BOTH INDICANTE
SECONDARY COLD FRONT WILL MOVE OFF NEW ENGL COAST LATE MON INTO
MON NIGHT. MODELS THEN CONTINUE TO HAVE DIFFICULTY WITH TIMING
AND STRENGTH OF UPPER SHRTWVS IN PROGRESSIVE FLOW. 06Z GFS
APPEARS AS LONE MODEL TO ADVERTISE SHRTWV OFF NEW ENGL COAST
EARLY THU...AND INCREASING WINDS N OF BALT CNYN TO 25 OR 30 KT
QUICKER THAN ECMWF/UKMET/GLOBAL GEM. TIMING OF COLD FRONT TOWARD
WEEKS END BECOMES MURKY AS WELL WITH LATEST GEFS AND ECMWF EPS
MEANS BETTER SUPPORTING MORE PROGRESSIVE ECMWF/UKMET. WITH THIS
MORNINGS UPDATES WILL NOT BE MAKING SIGNIFICANT ADJUSTMENTS TO
PREVIOUS GRIDS/FORECASTS THO GIVEN AT LEAST MODERATE LEVELS OF
FORECAST UNCERTAINTY.

GULF OF MAINE BUOY 44005 WAS ALREADY UP TO 7 FT AT 12Z WHICH IS
2 FT ABOVE 06Z MULTIGRID WAVEWATCH III. 00Z ECMWF WAVE MDL IS
SLIGHLY BETTER INITIALIZED HERE. OVER NEXT 12 TO 18 HRS WILL USE
2:1 BLEND WITH HIGHER ECMWF WEIGHT.

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

THE LTST GOES WV IMGRY INDC AN UPR RDG OVR THE COAST...AN UPR
LOW N OF THE GRT LKS...AND A SHRTWV TROF OVR THE GRT LKS. ASCAT
FM 02Z INDC AN AREA OF SFC HIGH PRES OVR SRN NT2...AND W TO SW
WINDS UP TO 20 KT INADVOF A FRONTAL BNDRY IN THE GRT LKS
RGN...ASSOC WITH THE AFOREMENTIONED SHRTWV TROF. THE 00Z MDLS
AGREE WELL ON THE TMG OF THE BNDRY MOVG INTO THE OFSHR WTRS IN
THE SHORT TERM...THO THE GFS IS SLGTLY STGR WITH THE SFC LOW AS
IT PASSES N OF THE AREA TDA INTO TNGT. THE 00Z MDLS INDC WNDS
AHD OF THE BNDRY WL INCRS T0 25-30 AHD OF THE FRNT...AS THE
FRNTL FRCG SHUD ALLOW FOR SOME MXG IN THE MRGNLLY STABLE
ENVRMT...ESP OVR THE GLF STRM. THE STGR WINDS ARE XPCTD TO MOVE
QUICKLY E OF THE AREA TNGT...THO THE FRNT IS XPCTD TO HANG UP
AND MOV SLOWLY S ALNG THE COAST...BEFORE BFLY STALLING OVR SRN
NT2 MON NGT INTO TUE. THE 00Z MDLS ARE AGREEING FAIRLY WELL ON
THE TMG OF THE BNDRY...AND NO MAJOR DIFFS NOTED IN THE SHORT
TERM. HOWEVER...THERE HAVE BEEN SOME DIFFS ON THE TMG AND
INTSNTY OF SHRTWVS ALNG THE FRNT. THE PREV 12Z UKMET RUN WAS A
BIT STGR WITH THE FIRST SHRTWV...AND WAS A BIT OF A STG OUTLIER.
HOWEVER...THE 00Z RUN HAS TRENDED TWD THE REST OF THE GUID...AND
MOST ALL SOLNS INDC A VERY WK FRNTL WAVE ON MON. THE H5 ENERGY
LOOKS TOO WK TO SUPPORT MUCH OF A SFC LOW...SO ATTM FAVORING A
WKR SOLN. IN ADDITION...THE GFS/ECWMF AGREE FAIRLY WELL...AND
INDC WNDS UP TO 25 KT IN THE SE NT2 WTRS LATE MON. AS A
RESULT...PLANNING ON GOING NO HIGHER THAN 25 IN SE NT2 THRU MON.
FURTHERMORE...THE 00Z GFS ALSO AGREES WELL WITH THE ECWMF ON TUE
WITH THE SECOND AND STGST OF THE SHRTWVS. THE GFS HAS TRENDED
SLGTLY WKR WITH THE WINDS FM THE 18Z RUN...AND ALL MDLS INDC THE
H5 ENERGY BCMG STRETCHED OUT...THO A LTL MORE CONSOLIDATED THAN
THE PREV H5 VORT MON. THE 12Z ECWMF INDC ABT 25 KT...AS DOES THE
GFS. AS A RESULT...SO PLANNING TO GO AS HIGH AS 25 KT WITH THIS
FRNTL WAVE AS WELL...THO WL HAVE A SLGTLY MORE EXPANSIVE AREA.

IN THE EXTENDED...THE 00Z GFS AND ECWMF START DIFFERING LATE WED
AND THU...ESP WITH SHRTWVS ROTATING ABT AN UPR LOW CTRD NR JAMES
BAY. THE 00Z ECWMF HAS BEEN VRY INCONSISTENT IN THE EXTENDED
WITH THE HANDLG OF THE ENERGY...AND SFC DVLPMT HAS BEEN CHANGING
FM RUN TO RUN AS WELL. THE GFS HAS SHOWN A LTL BETTER RUN TO RUN
CONSISTENCY...AND INDC A WK FRNTL BNDRY THRU THE N PTN WED. THE
GFS HAS BACKED OFF THE WNDS AND STRENGTH OF THE BNDRY...AND INDC
ABT 25 KT IN NT1. THIS SEEMS RSNBL GIVEN THE WK MID-LVL ENERGY
ASSOC WITH THIS SYS.

IN ADDITION...THE 00Z MDLS ARE INDCG A STGR BNDRY THRU THE N PTN
THU...WITH GFS WNDS UP TO 30 KT IN THE CAA. ALTHO THE STRENGTH
OF THIS BNDRY WOULD INDC THE PSBLTY OF GALES...THE LACK OF A
CONSISTENT SOLN CREATES HIGH UNCERTAINTY...AND CONFDC IN GALES
IS LOW AS A RESULT. THE GFS HAS ALSO BACKED OFF THE CSTL DVLPMT
THU NGT ALNG THE GA/SC COAST...AND AGREES WELL WITH THE UKMET
AND ECWMF ON HIGH PRES BLDG IN FM THE W. ALTHO NOT HIGHLY
CONFDNT WITH THE GFS...PLANNING ON FLWG IT THRU THE FCST PD...AS
IT SEEMS TO BE A RSNBL CMPRMS AND HAS SHOWN THE LEAST
VARIABILITY.

.SEAS...00Z NWW3 AND ECMWF WAM ARE INIT WITHIN A FT IN THE OFSHR
WTRS...WITH SEAS LESS THAN 6 FT OVR THE AREA UNDER THE INFLUENCE
OF HIGH PRES. NO MAJOR DIFFS WERE NOTED INTO WED NGT...BEFORE
THE ECWMF WAM BUILDS SEAS ABT 6 FT HIGHER THAT NWW3 WED NGT INTO
THU WITH A STGR WX PTTN DEPICTED BY THE ASSOC WX MDL. TO REMAIN
CONSISTENT WITH THE PREFERRED WX MDL...WL GENLY STAY NR THE 00Z
NWW3 MDL.

.EXTRATROPICAL STORM SURGE GUIDANCE...N/A

.WARNINGS...PRELIMINARY.

.NT1 NEW ENGLAND WATERS...
     NONE.

.NT2 MID ATLC WATERS...
     NONE.

$$

.FORECASTER CLARK/KELLS. OCEAN PREDICTION CENTER.



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