

299 

AGNT40 KWNM 161431

MIMATN



MARINE WEATHER DISCUSSION FOR N ATLANTIC OCEAN

NWS OCEAN PREDICTION CENTER WASHINGTON DC

1031 AM EDT TUE AUG 16 2016



.FORECAST DISCUSSION: MAJOR FEATURES/WINDS/SEAS/SIGNIFICANT

.WEATHER FOR THE NORTH ATLANTIC OCEAN W OF 50W FROM 30N TO 50N.



ALTHOUGH THE UPPER LEVEL HIGH PRES STILL REMAINS STRONG AND

DOMINANT SYNOP FEATURE ACROSS THE FORECAST WATERS...IT WILL START

TO WEAKEN IN THE SHORT TERM AND WILL REMAIN WEAK THROUGH THE

EXTENDED PERIOD.



THE LATEST SAT IMG INDC SCT TSTMS OVER THE CENTRAL WATERS WITH

STRONGER TSTMS JUST E OF THE BALT CANYON. THE CURRENT SYNOP

OBSERVATIONS INCLUDING THE EARLIER ASCAT AND RSCAT PASSES SHOW MAX

WINDS TO 20 KT BUT SLIGHTLY HIGHER IN AREAS WITH TSTMS. AT 12Z THE

NCEP MAP HAS A QUASI-STATIONARY FRONT ACROSS THE CENTRAL WATERS

WHICH IS INLINE WITH THE OBSERVED TSTMS. BROAD HIGH PRES 1026 MB E

OF THE REGION HAS ITS WRN RIDGE EXTENSION ACROSS THE WATERS. THE

PRES GRADIENT IS FAIRLY WEAK AND ALL THE MODELS HAVE INTITIALIZED

WELL WITH THE OBSERVATIONS. THE MODELS ARE ALSO IN GOOD AGREEMENT

IN THE SHORT TERM ON STARTING TO WEAKEN THE HIGH PRES OVER THE

WATERS. OTHERWISE THE GLOBAL MODELS AGREE ON MAINTAINING A RELAXED

PRES GRADIENT THRU THE FORECAST PERIOD AND SO THE WINDS WILL

REMAIN BELOW GALE FORCE THRESHOLD. WILL MAKE NO MAJOR CHANGES TO

THE PREVIOUS FORECAST AND WILL STAY WITH GFS. IN THE SHORT TERM

HIGH PRES OVER THE NRN WATERS WILL MOVE E AND ALLOW THE RIDGE TO

BE CONFINED TO THE FAR SRN WATERS. LOW PRES WILL THEN MOVE INTO

THE NRN WATERS. THE SEAS ARE EQUALLY LOW RANGING BETWEEN 3 AND 6

FT OVER THE NRN WATERS AND 2 TO 4 FT OVER THE SRN WATERS. NWW3

FITS VERY WELL WITH THE SEAS PATTERN AND IS CLOSE TO THE

ECMWFWAVE. WILL CONTINUE WITH NWW3 FOR THE SEAS.



-----------------------------------------------------------------

PREVIOUS DISCUSSION...



STRONG UPPER LEVEL HIGH PRES WHICH HAS PERSISTED FROM THE SE AND

MID ATLC STATES EASTWARD TOWARD THE CENTRAL ATLANTIC OCEAN WILL

FINALLY BEGIN TO BREAK DOWN TOWARD THE LATER HALF OF THE WEEK.



SHORT TERM...THE 00Z GLOBAL MODELS ARE REMAINING IN VERY GOOD

AGREEMENT ACROSS THE REGION...AND ARE REMAINING FAIRLY CONSISTENT

AS WELL. THE LATE EVE ASCT AND RSCT OVERPASSES INDICATED MAX

WINDS OF 15 TO 20 KT OVR FAR SRN AND FAR NE NT2 WTRS. THE 06Z

PRELIM OPC-NCEP SFC ANALYSIS SHOWS A WEAK COLD FRONT BCMG STNRY

OVR NRN NT2 WTRS...WITH SFC HIGH PRES COVERING AREAS S AND N OF

THE FRONT. FOR THE AM FCST PACKAGE WE WILL NOT MAKE SIGNIFICANT

CHANGES TO THE PREV FEW OPC FCSTS AS THE GENERAL WX SCENERIO

REMAINS THE SAME OVR THE WTRS THRU THU NITE. THE FRONT OVR NRN

NT2 WTRS EARLY THIS MORNING WILL RETURN N AS A WARM FRONT DURING

THE DAY TODAY INTO TONITE. LOW PRES WILL TRACK FROM THE GRT LKS

TOWARD NRN NEW ENGLAND TODAY...AND PASS N OF THE WTRS TONITE INTO

WED. A COLD FRONT ASSOC WITH THIS LOW WILL PASS SE OVR NT1 WTRS

WED INTO WED NITE...AND THEN STALL OVR NRN NT2 WTRS (39N-40N)

THU. THE NEXT COLD FRONT WILL APPROACH NT1 WTRS FROM THE NW EARLY

THU NITE...AND PASS SE OVR THESE WTRS LTR THU NITE INTO EARLY

FRI. TO THE S...OVR CENTRAL AND SRN NT2 WTRS...A HIGH PRES RIDGE

WILL DOMINATE FOR THE NEXT COUPLE OF DAYS...WITH A SLOW WEAKENING

OF THE RIDGE LKLY BY THU INTO FRI. FOR THE EARLY AM PACKAGE WE

WILL POPULATE THE FCST WITH A 50-50 BLEND OF THE PREV FCST AND

00Z GFS 10M WINDS. THIS WILL HELP TO MAINTAIN FCST CONTINUITY AND

RESULT IN NO MAJOR CHANGES TO THE ONGOING OPC FCST. THE LATEST

SATELLITE...RADAR AND LIGHTNING DENSITY IMAGERY DOES INDICATE

SCTD TSTMS OCCURRING MAINLY OVR NRN NT2 WTRS NR THE FRONT...WITH

ISOLATED TSTMS FURTHER S OVR SRN NT2 WTRS. THE BEST CHANCE FOR

STRONGER TSTMS WILL BE NR EACH FRONTAL SYSTEM OVR THE WTRS FOR

THE NEXT FEW DAYS WITH LOCALLY GUSTY WINDS NR GALE FORCE AND

ROUGH SEAS POSSIBLE NR THE STRONGER TSTMS.



LONG TERM...THE 00Z GLOBAL MDLS BEGIN TO DIVERGE SOMEWHAT FRI INTO

THE WKND. THE 00Z ECMWF HAS REMAINED QUITE CONSISTENT FROM THE

12Z CYCLE FROM MON...AND IS ALSO IN GOOD AGREEMENT WITH THE 00Z

UKMET AND LATEST MED RANGE GUIDANCE FROM WPC. AS A RESULT WE WILL

TRANSITION OUR GRIDS AND FCST TOWARD THE 00Z ECMWF FOR LATER FRI

INTO SAT NITE OVR THE WTRS. THIS WILL ALSO RESULT IN LITTLE

CHANGE FROM THE PREV FCST FOR THE EARLY AM PACKAGE WITH A FRONT

ONCE AGAIN BECOMING NRLY STNRY OVR NRN OR CENTRAL NT2 WTRS FRI

NITE INTO SAT NITE AS HIGH PRES BUILDS N OF THE WTRS.



SEAS...BOTH THE 00Z WNA WAVE WATCH III AND 00Z ECMWF WAM WAVE

MODELS APPEAR TO HAVE INITIALIZED WELL OVR THE WTRS PER THE

LATEST OBS AND ALTIMETER DATA. TO MATCH THE WIND FCST AS NOTED

ABV...WE WILL POPULATE THE GRIDS AND FCST WITH A 50-50 BLEND OF

THE PREV FCST AND 00Z WW3 MDL GUID FOR TODAY INTO FRI...AND THEN

TRANSITION TOWARD THE 00Z ECMWF WAM MDL OUTPUT THEREAFTER.



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





.WARNINGS...PRELIMINARY.



.NT1 NEW ENGLAND WATERS...

     NONE.



.NT2 MID ATLC WATERS...

     NONE.



$$



.FORECASTER MUSONDA/MILLS. OCEAN PREDICTION CENTER.

