Marine Interpretation Message
Issued by NWS

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000
AGNT40 KWNM 301440
MIMATN

MARINE WEATHER DISCUSSION FOR N ATLANTIC OCEAN
NWS OCEAN PREDICTION CENTER WASHINGTON DC
1040 AM EDT TUE AUG 30 2016

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

THE SAT IMG INDC A HIGH PRES RIDGE OVER THE NRN WATERS. THE
LATEST OBSERVATIONS SHOW HIGH WINDS OVER THE SRN WATERS. AT 12Z
LOW PRES JUST E OF NEW FOUNDLAND HAS A COLD FRONT THAT STRETCHES
SW AND BECOMES STNRY OVER THE CENTRAL WATERS. THE PRES GRADIENT
REMAINS SLACK OVER THE NRN WATERS AND SLIGHTLY TIGHT OVER THE SRN
WATERS. T.D EIGHT STILL OVER THE SRN WATERS NOW NEAR 34.3N 75.3W
AND NOW MOVING NNW AT 4 KT. SEE THE NHC FOR THE LATEST ON TD
EIGHT. THE SEAS ARE HIGHER OVER THE SRN WATERS IN THE VICINITY OF
TD EIGHT. NWW3 MULTI GRID WAVE MODEL FITS GENERALLY WELL WITH THE
SEAS PATTERN BUT UNDERDONE NEAR TD EIGHT. THE ECMFWAVE IS EQUALLY
UNDERDONE NEAR THE TD. BOTH WAVE MODELS HAVE VERY SIMILAR SOLUTION
AND SO WILL STAY WITH WNA.

THE ECMWFHR/GFS/UKMETHR/CMC/NOGAPS/ MODELS HAVE DIFFERENCES ON
ALMOST ALL THE SYNOP FEATURES THAT WILL IMPACT MOSTLY THE NT2
WATERS IN THE SHORT TERM AND WILL INCLUDE NT1 WATERS IN THE
EXTENDED PERIOD. DIFFERENCES ON TD EIGHT ARE MAINLY ON THE
STRENGTH OF THE WINDS. INITIALLY MODEL WINDS ARE WITHIN 10 KT
DIFFERENCE WITH ECMWFHR BEING THE WEAKEST AND UKMETHR AND CMC ON
THE HIGH END WHILE GFS AND NOGAPS LIE IN BETWEEN. UKMETHR GFS AND
CMC HAVE WINDS ASSOCIATED WITH TD EIGHT INCREASING EARLIER THAN
ECMWFHR. OTHERWISE THE MODELS HAVE GENEARLLY SHOWN A CLOSE TRACK
OF TD EIGHT. THE OTHER DIFFERENCES ARE ON AWEAK LOW THAT WIL FORM
NEAR GA COAST. ONLY UKMETHR AND GFS DEVOLP A WEAK LOW OFF GA COAST
AND SHOW IT PASSING NE OVER THE ERN PARTS OF THE SRN WATERS WITH
ELEVATED WINDS OVER ERN POTIONS. THE MODELS HAVE MAJOR DIFFERENCES
WITH TD NINE MAINLY ON THE TIMING AND TWD THE END ON THE TRACK.
ECMWFHR APPEAR TO BE SLIGHTLY FASTER THAN THE REST IN THE SHORT
TERM AND IN THE LONG TERM GFS SHOWS THE STORM W OF THE OTHER
MODELS. FOR THIS PACKAGE WILL NOT MAKE ANY MAJOR CHANGES TO THE
PREVIOUS FORECAST AND WILL CONTINUE WITH GFS.


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

SUMMARY...00Z NCEP SFC ANALYSIS SHOWS T.D. EIGHT CENTERED OVER
ZONE 930 IN THE SRN NT2 WTRS...WITH T.D. NINE CENTERED ABOUT 90
NM NW OF WRN CUBA...HURCN GASTON IS CENTERED ABOUT 500 NM E OF
BERMUDA...AND A COLD FRONT EXTNDS NE TO SW ACROSS THE GEORGES BANK
AND SRN NEW ENGLAND WTRS. LATEST AVAILABLE ASCAT AND ASCAT HI-RES
PASSES FROM EARLIER THIS MORNING SHOW AREAS OF WINDS TO 20 KT
ALONG THE NRN PERIPHERY OF T.D. EIGHT...THERE WAS NO COVERAGE OVER
THE CENTER OF THE SYSTEM. LIGHTNING DENSITY PRODUCT DATA AT 0650Z
INDICATES SCATTERED SHOWERS AND TSTMS OVER THE SRN ZONES OF THE NT2
WTRS...AND AROUND THE N AND NW SEMICIRCLES OF T.D. EIGHT.

MODELS...THE 00Z GEM/GFS/UKMET BRING A FAIRLY STRONG LOW NE ACROSS
THE NT2 WTRS ON THU AND THU NITE...WHILE THE 00Z ECMWF IS SIGNIF
SLOWER AND WEAKER WITH THIS LOW. THE 00Z GFS ALSO LOOKS CLOSE TO
THE OFFICIAL NHC TRACK FORECASTS FOR T.D. EIGHT AND T.D.
NINE...SO IT APPEARS THAT THE 00Z GFS 30M SOLN IS REPRESENTATIVE
ENUF TO BE USED FOR THE WIND GRIDS OVER THE ENTIRE FCST PERIOD. AM
NOT PLANNING TO MAKE ANY SIGNIF CHANGES TO THE CURRENT FCST
TREND...UNLESS THERE ARE SIGNIF CHANGES TO THE FCST TRACKS OF T.D.
EIGHT AND/OR T.D. NINE.

SEAS...00Z WNA WAVEWATCH III AND 00Z ECMWF WAM BOTH INITIALIZED
REASONABLY WELL OVER THE OFSHR WTRS...BUT IT IS POSSIBLE THEY MAY
BOTH BE A FEW FEET TOO LOW AROUND T.D. EIGHT. IN ORDER TO BE
CONSISTENT WITH THE PREFERRED 00Z GFS SOLN...WILL USE THE 00Z WNA
WAVEWATCH III FOR THE ENTIRE FCST PERIOD.

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


.WARNINGS...PRELIMINARY.

.NT1 NEW ENGLAND WATERS...
     NONE.

.NT2 MID ATLC WATERS...
.ANZ915...HUDSON CANYON TO THE GREAT SOUTH CHANNEL...
     TROPICAL STORM WED NIGHT.
.ANZ920...BALTIMORE CANYON TO THE GREAT SOUTH CHANNEL...
     TROPICAL STORM WED INTO WED NIGHT.
.ANZ905...THE GREAT SOUTH CHANNEL TO THE HAGUE LINE...
     TROPICAL STORM WED NIGHT.
     TROPICAL STORM POSSIBLE THU.
.ANZ910...EAST OF THE GREAT SOUTH CHANNEL AND SOUTH OF 39N...
     TROPICAL STORM WED NIGHT.
     TROPICAL STORM POSSIBLE THU.
.ANZ828...INNER WATERS FROM CAPE CHARLES LIGHT TO CURRITUCK BEACH LIGHT...
     TROPICAL STORM TONIGHT INTO WED.
.ANZ925...OUTER WATERS FROM BALTIMORE CANYON TO HATTERAS CANYON...
     TROPICAL STORM TONIGHT INTO WED NIGHT.
     TROPICAL STORM POSSIBLE SAT INTO SAT NIGHT.
.ANZ830...INNER WATERS FROM CURRITUCK BEACH LIGHT TO CAPE HATTERAS...
     TROPICAL STORM TONIGHT INTO WED.
     TROPICAL STORM POSSIBLE FRI NIGHT.
.ANZ833...INNER WATERS FROM CAPE HATTERAS TO CAPE FEAR...
     TROPICAL STORM TONIGHT.
     TROPICAL STORM POSSIBLE FRI NIGHT.
.ANZ930...OUTER WATERS FROM HATTERAS CANYON TO CAPE FEAR...
     TROPICAL STORM TONIGHT INTO WED.
     TROPICAL STORM POSSIBLE FRI NIGHT INTO SAT.
.ANZ835...INNER WATERS FROM CAPE FEAR TO 31N...
     TROPICAL STORM POSSIBLE THU NIGHT INTO FRI NIGHT.
.ANZ935...OUTER WATERS FROM CAPE FEAR TO 31N...
     TROPICAL STORM POSSIBLE FRI INTO FRI NIGHT.

$$

.FORECASTER MUSONDA/SCOVIL. OCEAN PREDICTION CENTER.



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