Marine Interpretation Message
Issued by NWS

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AGNT40 KWNM 191236
MIMATN

MARINE WEATHER DISCUSSION FOR N ATLANTIC OCEAN
NWS OCEAN PREDICTION CENTER WASHINGTON DC
836 AM EDT SAT APR 19 2014

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

LOW PRES OVER NRN FLORIDA HAS A STNRY FRONT EXTENDING NEWD OFF THE
SE COAST WHICH IN COMBININATION WITH STRONG HIGH PRES TO THE N IS
SUPPORTING A STRONG ENELY GRADIENT N OF THE FRONT INTO THE CNTRL
NT2 WTRS. PER BUOY 41036 BLV MARGINAL GALES ARE OCCURING IMMED N
OF THE FRONT. MAX SEAS IN THIS GRADIENT ARE IN THE 7-9 FT RANGE
WHICH ARE BEING HANDLED RSNBLY WELL BY THE 06Z WAVEWATCH III AND
00Z ECMWF WAM.

OVER THE SHORT TERM...THE LATEST MDLS ARE IN RSNBLY GOOD AGRMT
THAT THE LOW WL MOVE OFF THE NE FLORIDA COAST TODAY...THEN TRACK
ENE INVOF THE SRN MOST NT2 WTRS TONITE INTO EARLY TUE WHILE
MAINTAINING A STRONG NNELY GRADIENT TO IS N ACRS THE SRN AND CNTRL
NT2 WTRS. WL USE A BLENDED 00Z/06Z GFS AND 00Z UKMET/ECMWF
SOLUTION FOR THIS GRADIENT. SO PER THIS BLENDED SOLUTION AND WL
START THE GALES ACRS THE SRN NT2 WTRS TODAY INSTEAD OF THE PREVLY
FCSTD TONITE. OTHERWISE NO MAJOR SHORT TERM CHNGS ARE PLANNED FOR
THE NEXT OFSHR FCST PACKAGE.

IN THE LONG RANGE...ALL OF THE LATEST MDLS GRNLY AGREE THAT AS THE
SFC LOW PASSES TO THE E OF THE SRN NT2 WTRS MON INTO TUE AND THE
HIGH PRES TO THE N WEAKENS THAT THE NNELY GRADIENT ACRS THE
SRN/CNTRL NT2 WTRS WL WEAKEN. WL CONT TO USE A BLENDED 00Z
GFS/ECMWF SOLUTION FOR MON/TUE. THEN ON WED WL USE A COMPROMISE
06Z/00Z GFS AND 00Z ECMWF SOLUTION FOR A NRN STREAM SFC LOW
PULLING A COLD FRONT OFSHR ACRS THE NRN WTRS. SO OVERALL NO MAJOR
LONG RANGE CHNGS ARE PLANNED FOR THE NEXT OFSHR FCST PACKAGE.


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

MAIN FCST PRBLM IS IN THE SHORT TERM...FM TNGT INTO EARLY MON.
THE LASTEST GFS  HAS COME NITO MUCH BTTR AGRMNT WITH THE
ECMWF/UKMET WITH REGARDS TO THE TRACK OF SFC LOW FCST TO MOV OFF
THE NRN COAST OF FLA TODAY. LOW WILL MOVE E ALONG 30N THRU SUN.
FOCUS OF WINDS WILL BE NW OF THIS LOW AND THE NE TO TO SW STNRY
FRONT ACROSS THE WATERS S OF HTTRS CNYN. GFS SEEMS TO HAV RSNBL
DPCTN OF NE FLOW OFF THE CAROLINA COAST TNGT...WITH SFC WINDS
MATCHING CLOSER TO THE 30M GFS WINDS. THESE WINDS SHOW WELL IN THE
0241Z ASCAT PASS.

WINDS WILL EASE A BIT THIS MRNG AS THE HIGH OVR THE NERN CONUS
WKNS. AS NEXT HIGH BUILDS S WHILE LOW PRES MVS OFF THE FL
COAST...XPCT NE WINDS TO INCRS THIS AFTN THRU SUN AFTN. GFS/
ECMWF/UKMET ALL INCRS WINDS TO 35 KT S OF HTTRS CNYN BY 12Z
SUN...SO WILL BUMP UP GALE WARNING START TIME TO LATE TNGT... WITH
HIGH CNFDC IN THIS GALE EVENT. THE GFS INCRS WINDS TO 40 KT S OF
CAPE FEAR LATE SUN. THE NEW UKMET LENDS SUPPRT TO 40 KT WINDS.
CNSDRNG THE MODEL IS TRNDING STRNGR WITH THE SFC RDG AND THESE
WINDS WL BE OVR AND OPPOSED TO THE GULF STREAM...WL INCRS WINDS TO
40 KT S OF CAPE FEAR. WINDS WILL GRADU DMNSH SUN NGT AND WILL END
GALES BY 12Z MON...THOUGH ITS QUITE PSBL THAT GALES WIL NEED TO BE
XTND INTO EARLY MON S OF BALT CNYN.

THE MODELS BGN TO HAVE SOME DFFRNCS IN THE TRACK OF THE ASSD UPR
LOW SUN NGT AND MON...WHICH INCRS IN TIME. THE GEM BCMS AN OUTLIER
QUICKLY TAKING THE UPR CNTR OFF TO THE NE. THE GFS/UKMET/ ECMWF
ARE SMLR IN THEIR TRACK THRU TUE...THOUGH WITH A GRADU INCRSNG
DFFRNC.

SECOND FCST CONCERN IS LATE WED. BY 12Z WED...THE MODELS AGREE ON
BRINGING COLD FRONT OFF THE COAST AND AGREE WELL ON PLACEMENT OF
THE FRONT. MAIN DFFRNC IS LOW OF SFC LOW OVR NEW ENGLAND. THE GFS
IS 200 NM S OF THE ECMWF/GEM AND WILL LIKELY LEAN TWDS THE
ECMWF...UNLESS THE 00Z RUN COMES IN MUCH DFFRNT. WPC MAN PROGS
RFLCT THE 12Z ECMWF. BY 12Z THU...THE GFS/UKMET FCST A 990 LOW NR
40N60W LEADING TO NW GALES OVR THE NERN WATERS. THE GEM AND 12Z
ECMWF ARE EACH QUITE A BIT DFFRNT. WILL WAIT FOR THE 00Z ECMWF...
BUT EITHER WAY...WILL CAP WINDS AT 30 KT ATTM DUE TO LOW CNFDC.


.SEAS...THE MULTIGRID WAVEWATCH III MODELS ININTLDS SEAS 1 TO 3 FT
TOO LOW IN THE MOD NE FLOW OFFSHR SAT NGT. XCPT THESE SEAS TO COME
A LTTL MORE IN LINE TODAY AS WINDS DMNSH A LTTL. THE ECMWF WAM
FCST QUITE SMLR...THOUGH WITH SEAS SEAS UP TWO FT HIGHER. THIS
LOOKS BTTR IN THE NE FLOW...SO WL USE THIS MODELS...BUMPING UP
SEAS 10 TO 15 PCT TNGT THRU SUN NGT IN THE STRNG NE FLOW...ESP OVR
THE GF STREAM


.EXTRATROPICAL STORM SURGE GUIDANCE...THE LATEST ESTOFS INDICATES
A POS SURGE OF 1 TO 2 FT DVLPNG SUN FM THE NRN FLA COAST TO S NC
COAST...AND ALSO JUST N OF CAP HTTRS TO SRN DELMARVA. THIS SURGE
ABATES SUN NGT. THE ETSS SURGE IS LESS THAN 1 FT. THE ESTOFS GDNC
SEEMS REASONABLE.



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

.NT1 NEW ENGLAND WATERS...
     NONE.

.NT2 MID ATLC WATERS...
.ANZ828...INNER WATERS FROM CAPE CHARLES LIGHT TO CURRITUCK BEACH LIGHT...
     GALE SUN INTO SUN NIGHT.
.ANZ925...OUTER WATERS FROM BALTIMORE CANYON TO HATTERAS CANYON...
     GALE SUN INTO SUN NIGHT.
.ANZ830...INNER WATERS FROM CURRITUCK BEACH LIGHT TO CAPE HATTERAS...
     GALE SUN INTO SUN NIGHT.
.ANZ833...INNER WATERS FROM CAPE HATTERAS TO CAPE FEAR...
     GALE TODAY INTO SUN NIGHT.
.ANZ930...OUTER WATERS FROM HATTERAS CANYON TO CAPE FEAR...
     GALE SUN INTO SUN NIGHT.
.ANZ835...INNER WATERS FROM CAPE FEAR TO 31N...
     GALE TODAY INTO SUN NIGHT.

$$

.FORECASTER VUKITS/PROSISE. OCEAN PREDICTION CENTER.



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