

384 

AGNT40 KWNM 041214

MIMATN



MARINE WEATHER DISCUSSION FOR N ATLANTIC OCEAN

NWS OCEAN PREDICTION CENTER WASHINGTON DC

814 AM EDT THU AUG 4 2016



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

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



UPDATE...06Z NCEP SFC ANALYSIS SHOWS A STATIONARY FRONT EXTNDG E

TO W ACROSS THE SRN NT2 WTRS...WITH A WEAK LOW CENTERED ALONG THE

FRONT OVER ZONE 930. THE ANALYSIS ALSO SHOWS A HI PRES RIDGE OVER

THE NT1 AREA. LATEST AVAIL ASCAT AND ASCAT HI-RES PASSES FROM LAST

NITE SHOW MAINLY 15 TO 20 KT WINDS OVER THE OFSHR WTRS...EXCEPT

FOR LIGHT WINDS OF 15 KT OR LESS ACROSS MUCH OF THE NT1 AREA.

LIGHTNING DENSITY PRODUCT DATA FROM 1100Z SHOWS SCATTERED SHOWERS

AND TSTMS OVER THE SRN NT2 WTRS.



MAIN WEATHER FEATURES...A WEAK LOW WILL MOVE E ACROSS THE SRN NT2

WTRS TODAY AND TONITE...THEN PASS E OF THE OFSHR WTRS FRI. A COLD

FRONT WILL APPROACH THE COAST FRI NITE AND SAT...MOVE SE OVER THE

OFSHR WTRS LATE SAT THRU SUN NITE...THEN STALL ACROSS THE SRN NT2

WTRS MON AND MON NITE WHILE WEAKENING. OTHERWISE...HI PRES RIDGING

WILL PREVAIL OVER THE OFSHR WTRS DURING THE FCST PERIOD.



MODELS...THE MED RNG MDLS ARE IN VRY GUD AGREEMENT THRU MON

NITE...AND THE MAX WINDS ARE NOT EXPECTED TO EXCEED 20 OR 25 KT. THE

GFS 10M SOLN LOOKS 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.



SEAS...THE WNA WAVEWATCH III AND ECMWF WAM BOTH INITIALIZED WELL

OVER THE OFSHR WTRS...AND ARE IN GUD OVERALL AGREEMNT WITH ONE

ANOTHER THRU THE FCST PERIOD WITH ONLY A FEW MINOR DIFFS NOTED.

AM GOING TO USE A 50/50 BLEND OF THE WNA WAVEWATCH III/ECMWF WAM

THRU THE FCST PERIOD TO SMOOTH OUT THE MDL DIFFS.



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



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

PREVIOUS DISCUSSION...



THE LTST GOES IR IMGRY INDC A FRONTAL BNDRY ACRS SRN NT2...WITH 

A WK WAVE TO THE ESE OF CAPE HATTERAS. THE 02Z ASCAT WIND

RETRIEVALS INDC UP TO 20 KT IN THE S TO SW FLOW AHEAD OF THE

FRONT...AND IN THE NE FLOW TO THE N OF IT. CRNT SFC RPRTS INDC ABT

THE SAME...AND THE 00Z GFS 10M WINDS ARE INIT WITHIN 5 KT OF THE

CRNT DATA. THE GFS INDC THE LOW WL MOVE E OF THE AREA TDA AND

TNGT...AND THE 00Z ECMWF/UKMET ARE IN EXCEPTIONALLY GUD AGRMT ON

THE TRACK OF THE LOW...THO SLGTLY WKR WITH THE WINDS IN THE SW

FLOW. THE 00Z NAM IS A LTL N OF THE GFS...AND THE 00Z GEM IS A BIT

FASTER...AND STGR. WITH THE GFS INIT WELL...AND IN GUD AGRMT IN

THE SHORT RANGE...PLANNING ON STAYING NR IT FOR THE FIRST CPL OF

DAYS IN THE FCST.



THE 00Z GFS REMAINS IN VRY GUD AGRMT WITH THE 00Z ECMWF/UKMET

THRUT THE REMAINDER OF THE FCST...ESP WITH THE NEXT FRONT THAT

MOVES OFF THE NEW ENGLAND AND MID ATLC COAST SAT INTO SAT

NIGHT...THEN CONTINUE SE THROUGH THE AREA SUN INTO MON. THE 00Z

MDLS ALL INDC IT IS A FAIRLY WK FEATURE...WITH WINDS NO MORE THAN

25 KT IN THE OFSHR WATERS AS IT MOVES S INTO NT2. THE GFS SEEMS

SLIGHTLY HIGH IN THE SW FLOW OVR THE GULF OF MAINE AS THE FRONT

APRCHS THE COAST...WITH 25 KT...SO PLANNING ON CAPPING AT 20 KT.

OTRW WITH THE MODELS IN VRY GUD AGRMT AND THE GFS BEING VRY

CONSISTENT...PLANNING ON USING THE GFS THRUT THE FCST PD...WHICH

WAS DONE IN THE PREV FCST. 



SEAS...WL BOOST SEAS SLGTLY FOR THIS MRNG WITH THE NE FLOW OVER

NE NT2...AS CRNT DATA INDC THE WAVE GUID IS INIT A LTL LOW.

OTRW...THE 00Z WAVEWATCH-III AND ECMWF WAM ARE BOTH INIT WITHIN A

FT OR TWO OF THE CRNT DATA...AND AGREE WELL THRUT THE FCST

PD...WHICH IS NOT SURPRISING WITH THE ASSOC WX MDLS IN VRY GUD

AGRMT. PLANNING ON USING A 50/50 BLEND OF THE TWO SOLNS...AS A

CMPRMS TO THE MINOR DIFFS.



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



.WARNINGS...PRELIMINARY.



.NT1 NEW ENGLAND WATERS...

     NONE.



.NT2 MID ATLC WATERS...

     NONE.



$$



.FORECASTER SCOVIL/KELLS. OCEAN PREDICTION CENTER.

