Marine Interpretation Message
Issued by NWS

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AGNT40 KWNM 301254
MIMATN

MARINE WEATHER DISCUSSION FOR N ATLANTIC OCEAN
NWS OCEAN PREDICTION CENTER WASHINGTON DC
854 AM EDT SAT JUL 30 2016

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

A COLD FRONT CONTS TO DRIFT SLOWLY S ACRS THE NRN AND CNTRL NT2
WTRS WITH MAX ASCD WINDS GNRLY UP TO 20-25 KT...HIGHEST ACRS THE
OUTERMOST WTRS. MAX ASCD SEAS...VERIFIED BY AN EARLIER JASON
ALTIMETER PASS...ARE LKLY IN THE 5-7 FT RANGE ACRS THE OUTERMOST
NRN NT2 WTRS WHICH ARE IN LINE WITH THE 06Z WAVEWATCH III AND 00Z
ECMWF WAM MDLS.

OVER THE SHORT TERM...THE LATEST MDLS PRESENT NO MAJOR FCST
PROBLEMS. OVERALL THE MDLS AGREE THAT THE COLD FRONT WL BCM NRLY
STNRY TODAY...THEN RETURN SLOWLY NWD AS A WARM FRONT TONITE INTO
SUN NITE WITH MAX ASCD WINDS GNRLY HOLDING IN THE 15-20 KT RANGE.
S0 WITH THE 06Z NAM/GFS RMNG CONSISTENT VS THEIR PREV RESPECTIVE
RUNS...PLAN ON CONTG TO USE THE PREVLY POPULATED 00Z GFS 10M BL
WINDS WITH JUST MINOR ADDITIONAL EDITS IN DEFERENCE TO THE 06Z GFS
AND 00Z ECMWF.

IN THE LONG RANGE...IN GNRL THE MDLS AGREE THAT THE WARM FRONT WL
BCM QSTNRY ACRS THE SRN NT1 WTRS MON THROUGH TUE WHILE SEVERAL
WEAK LOWS TRACK E ALONG THE FRONT...THEN SHIFT BACK SLOWLY S ACRS
THE NRN/CNTRL NT2 WTRS AS A COLD FRONT TUE NIGHT INTO WED NITE.
MAINLY DUE TO THE LATEST MDLS CONTG TO HV TIMING AND TRACK
DIFFERENCES IN RGRDS TO THE SFC LOWS TRACKING E ALONG THE
FRONT MON INTO TUE NITE...WHICH RESULTS IN LOW/MOD FCST
CONFIDENCE...BELIEVE THE PREVLY POPULATED COMPROMISE 00Z
GFS/ECMWF SOLUTION FOR MON THRU WED NITE STIL LOOKS LIKE A WISE
COURSE TO FOLLOW FOR NOW. SO DO NOT PLAN ON MAKING ANY SIG LONG
RANGE CHNGS IN THE NEXT OFSHR FCST PACKAGE.



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

SHORT TERM...LOW PRES HAS MOVED E OF GEORGES BANK AND IS NOW
LOCATED NEARLY 150 NM S OF CENTRAL NOVA SCOTIA PER THE 06Z PRELIM
OPC-NCEP SFC ANALYSIS. THE LOW WILL CONTINUE TO MOVE E-NE AWAY
FROM THE WTRS TODAY. THE ASSOC COLD FRONT EXTENDS SW OVR NRN AND
CENTRAL NT2 WTRS TOWARD CAPE HATTERAS AT THIS TIME. A FEW SCTD
TSTMS WERE BEING DETECTED BY THE LATEST LIGHTNING DENSITY IMGRY
OVR MAINLY NE AND CENTRAL NT2 WTRS RIGHT ALONG THE FRONT. THE LATE
EVE ASCAT PASS INDICATED MAX WINDS NR 25 KT FROM FROM SW OVR NE
NT2 WTRS JUST AHEAD OF THE FRONT...WITH WINDS GENERALLY 20 KT OR
LESS ELSEWHERE. THESE WIND SPEEDS AND DIRECTIONS MATCHED WELL WITH
THE 00Z GFS 10M WINDS...WITH THE REMAINING GLBL MDLS ALSO
INITIALIZING QUITE WELL OVR THE REGION EARLY THIS MORNING. FOR THE
EARLY AM PACKAGE...WE WILL STAY CLOSE TO THE 00Z GFS 10M WINDS FOR
TODAY INTO SUN NITE. THE COLD FRONT WILL BECOME NEARLY STATIONARY
OVR NRN NT2 WTRS DURING THE DAY TODAY. WEAK LOW PRES AREAS WILL
TRACK E-NE ALONG THE FRONT BEGINNING SUN. THERE ARE SOME MINOR
TIMING AND PSN DIFFERENCES NOTED IN THE 00Z GLBL MDLS BEGINNING
SUN NITE. AS A RESULT...WE WILL TRANSITION TO A 50-50 BLEND OF THE
00Z GFS AND 00Z ECMWF BY 06 MON TO ACCT FOR THESE DIFFERENCES.
ALSO TSTMS...PER THE LATEST SREF TSTMS GUID ARE FCST TO INCREASE
AT TIMES OVR MAINLY NRN AND CENTRAL NT2 WTRS TODAY INTO MON.
LOCALLY HIGHER WINDS POTENTIALLY NR OR EXCEEDING GALE FORCE AND
ROUGH SEAS CAN BE EXPECTED IN OR NR THE HEAVIER TSTMS.

LONG TERM...WK LOW PRES AREAS WILL CONT TO TRACK E-NE ALONG THE
FRONT OVR THE NRN NT2 WTRS MON NITE INTO TUE. A FINAL LOW IS
STILL FCST TO MOVE E OF THE WTRS TUE NITE INTO WED AS HIGH PRES
BUILDS E AND SE INTO THE NT1 WTRS. THE ASSOC COLD FRONT WILL THEN
SLIDE SE OVR CENTRAL AND THEN SRN NT2 WTRS WED INTO WED
NITE...WITH THE HIGH BUILDING S INTO NRN AND POTENTIALLY CENTRAL
NT2 WTRS. FOR THE EARLY AM PACKAGE...WE WILL CONT TO USE A 50-50
BLEND OF THE 00Z GFS AND 00Z ECMWF FOR MON NITE INTO WED NITE
BEFORE TRANSITIONING TO MAINLY THE 00Z ECWMF LTR WED NITE AND
BEYOND. THIS BLEND APPEARS TO BEST FIT A GENERAL MODELS
CONSENSUS...MAINTAINS CONTINUITY FROM THE PREV FCST...AND IS
GNRLY CLOSE TO THE LATEST WPC MED RANGE GUID.

SEAS...THE 00Z WNA WAVEWATCH III AND 00Z ECMWF WAM HV BOTH
INITIALIZED THE CURRENT SEAS QUITE WELL AGAIN EARLY THIS MORNING
BASED ON THE LATEST OBS AND ALTIMETER DATA. FOR THE EARLY AM
PACKAGE WE WILL REMAIN CLOSE TO THE WW3 FOR TODAY INTO SUN
NITE...TRANSITION TO A 50-50 BLEND OF THE WW3 AND WAM MDLS LATER
SUN NITE INTO WED NITE...AND THEN 100 PERCENT ECMWF WAM
THEREAFTER. THIS WILL MATCH WELL WITH THE FCST WINDS AS DESCRIBED
ABV.

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


.WARNINGS...PRELIMINARY.

.NT1 NEW ENGLAND WATERS...
     NONE.

.NT2 MID ATLC WATERS...
     NONE.

$$

.FORECASTER VUKITS/MILLS. OCEAN PREDICTION CENTER.



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