Marine Interpretation Message
Issued by NWS

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000
AGNT40 KWNM 311921
MIMATN

MARINE WEATHER DISCUSSION FOR N ATLANTIC OCEAN
NWS OCEAN PREDICTION CENTER WASHINGTON DC
321 PM EDT FRI JUL 31 2015

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

CRNT GOES VIS IMGRY INDC A CDFNT OVR NT1 AND NRN NT2...AND ALSO
AN AREA OF LOW PRES ABOUT 90 NM NE OF CAPE HTRS WITH A TROF
EXTENDING TO THE SSW. THE IMGRY AND THE LGTNG DENSITY PROD BOTH
INDC AN AREA OF SHOWERS AND TSTMS ALNG THE TROF IN THE UNSTABLE
EVRNMT OVR THE GLF STRM...AND ALSO A FEW ALNG THE FRNTL BNDRY. WL
MAINTAIN MENTION OF TSTMS AND SHOWERS IN THE FCST...BUT MAIN
CONCERN IS GALES IN SW FLOW OVR NT2 ZONES. ASCAT FM 1520 UTC INDC
25 TO 30 KT AHD OF THE TROF AND FRNTL BNDRY...WITH A VRY SML AREA
OF GALES OVR NRN NT2. RECENT SFC RPRTS INDC WNDS UP TO 25 KT OVR
NT2...AND TO 35 KT JUST SE OF NRN NT2 WTRS. THE 12Z GFS 30M WNDS
ARE INIT JUST A TAD LOW AHD OF THE BNDRY...SO PLANNING ON BOOSTING
WNDS INITIALLY INVOF THE FRNT TO MATCH CRNT DATA. OTRW WL CONT
WITH 30M OVR THE GULF STRM AND SE...AND 10M WNDS TO THE N OF THE
GULF INTO 18Z SAT...AS THE 12Z ECWMF/UKMET ARE INIT LOW...THO
SYNOP FEATURES MATCH GFS.

THE 12Z MDLS RMN IN GENLY GUD AGRMT ON THE OVERALL PTTN INTO
MON...AND ALL INDC THE CRNT BNDRY WL STALL OVR NT2 WHILE WKNG. THE
12Z GEM SEEMS TO HAVE SOME FEEDBACK ISSUES...AS IT OVR DVLPS A
LOW ALNG THE FRNT. ATTM PLANNING ON USING 10M GFS WNDS INTO 00Z
TUE...AS A RESULT OF THE DECENT MDL AGRMT. HOWEVER...12Z MDL SOLNS
START DVRGING AT 00Z TUE...WITH THE GFS BCMG FASTER WITH THE NEXT
SYS THRU THE W ATLC. THE 12Z ECWMF IS ABT 12 HOURS SLOWER BY 12Z
WED...AND IT SEEMS TO HAVE A BIT MORE CREDIBILITY WITH THE UPR LVL
PTTN INDCG A SLGTLY AMPLIFIED RDG IN THE ERN ATLC THAT SHUD SLOW
DN THE FLOW A BIT. THE 12Z UKMET AND GEM ARE MUCH DIFF...AND INDC
ANTHR STG LOW WL DVLP IN THE EXTENDED...AND BOTH SEEM TO HAVE
FEEDBACK PRBLMS. FOR THE FCST...PLANNING ON USING A CMPRMS BTWN
THE 12Z GFS AND ECMWF...AND WL TIMESHIFT THE GFS 6 HOURS SLOWER.

SEAS...THE 12Z MWW3 AND ECMWF WAM HV BOTH INIT SEAS A TAD LOW
OVER THE FAR E NT2 WTRS E OF CAPE HTRS...BUT ELSWHR LOOK RSNBL.
THE MDLS SEEM RSNBL INTO 00Z TUE...BUT TMG ISSUES WITH ASSOC WX
MDLS CREATE DIFFS WITH THE WAVE MDLS. FOR THE FCST...PLANNING ON
USING A SMLR STRATEGY AS WITH THE WX MDLS...AND TIMESHIFT 12Z MWW3
SEAS 6 HOUR SLOWER. THIS BRINGS WAVE MDLS CLOSE...SO WL
SUBSEQUENTLY USE A 50/50 BLEND OF THE TIMESHIFTED MWW3 GRIDS WITH
THE 12Z ECWMF WAM GRIDS FOR THE FCST FROM 00Z TUE ONWARD.

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

.WARNINGS...PRELIMINARY.

.NT1 NEW ENGLAND WATERS...
     NONE.

.NT2 MID ATLC WATERS...
.ANZ925...OUTER WATERS FROM BALTIMORE CANYON TO HATTERAS CANYON...
     GALE TONIGHT.

$$

.FORECASTER KELLS. OCEAN PREDICTION CENTER.


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