

926 

AGNT40 KWNM 182059

MIMATN



MARINE WEATHER DISCUSSION FOR N ATLANTIC OCEAN

NWS OCEAN PREDICTION CENTER WASHINGTON DC

459 PM EDT THU AUG 18 2016



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

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



THE 18Z OPC SFC ANALYSIS AND THE LATEST GOES IR SATELLITE IMAGERY

INDICATE A SLOW MOVG CDFNT EXTENDING W ACRS NRN NT2 WTRS AND A

NEWLY FORMED WK LOW OFF SRN NEW JERSEY COAST IN OUTER ANZ820. THE

LIGHTNING DENSITY ALG WITH LTNG STRIKE DATA INDC SHOWERS AND

TSTMS ALONG THE FRONT MAINLY IN THE MORE UNSTABLE CONDS OVER THE

GULF STREAM. ADNL SHOWERS ARE NOTED FM RADAR DATA EXTENDING

FARTHER N INTO SRN NT1 WTRS AND ALSO IN SW FLOW OFF SE COAST BUT

HEAVIER ACTVTY IS ALG A LEE TROF INLAND OVR CAROLINAS. NEWLY

POPULATED WX GRIDS INDC SHOWERS AND TSTMS CONSISTENT WITH THE

CRNT CONDITIONS. OTRW CRNT SFC RPRTS AND ASCAT-A AND B DATA INDC

WINDS TO 20 KT IN THE SW FLOW AHD OF THE FRONT...AND 5 TO 10 KT N

OF THE FRONT. THE 12Z GFS WINDS ARE INIT WELL WHEN COMPARED WTIH

THE CRNT DATA...AND INDC WINDS WILL DCRS AS THE LOW MOVES QUICKLY

OFF TO THE E. 12Z ECWMF/UKMET/GEM/NAM ALL AGREE FAIRLY WELL WITH

THE GFS ON THE TIMIMG OF THE COLD FRONT AND ON THE STRENGTH OF

THE WINDS. STARTED OUT WITH 12Z GFS 10M WINDS WHICH APPEAR

REPRESENTATIVE AND CONSISTENT WITH PREVIOUS RUNS ON CURRENT

SYSTEM.



THE 12Z GFS AGREES FAIRLY WELL WITH THE 12Z ECMWF/UKMET THRU THE

REMAINDER OF THE FCST PD ON THE SYNOP PTTN...AND INDC A WKR CD

FRONT WL MOVE S INTO NT1 AREA TNGT INTO FRI. THE 12Z GFS CONTINUES

TO SHOW THE FIRST FRONT WL DRIFT S OVER NT2 WTRS WHILE WKNG INTO

SAT...BEFORE ANOTHER STRONGER CDFNT MOVES INTO THE WRN ATLC LATE

SUN NIGHT THRU MON NIGHT. THE GFS HAS BEEN CONSISTENT ON THE

TIMING AND STRENGTH OF THE FRONT...AND GFS AGREES WITH ECMWF/UKMET

WINDS WL NOT INCRS TO MORE THAN 20 KT IN THE SRLY FLOW OVR NT1

WTRS WHERE BL CONDS ARE MORE STABLE. PREFER THE 12Z GFS OVR THE

SOMEWHAT WEAKER ECMWF WITH NLY TO 25 KT DVLPG IN COOLER

AIRMASS...COOLER THAN IN RECENT WEEKS...BEHIND THE FRONT AND

STAYED WITH GFS THRU MON NIGHT. ON TUE WITH HIGH PRES BUILDING OVR

THE WATERS FAVORED THE 12Z ECMWF WITH ITS SOMEWHAT HIGHER WINDS

OVER OUTER ZONES IN N TO NE FLOW AND MORE IN LN WITH UKMET. HWVR

MDL AGRMT ON SYNOP FEATURES REMAINS GOOD.



.SEAS...18Z RA1 INDC THE HIGHEST SEAS...6 FT OR HIGHER...ASSOC

WITH THE STRONGER WIND ALONG THE AFOREMENTIONED FRNTL BNDRY HAVE

MOVED E OF THE OFSHR WTRS. THE 12Z WNA NWW3 AND ECWMF WAM ARE

INIT WELL WHEN COMPARED WITH THE CRNT DATA...AND INDC THE SEAS WL

CONT TO SUBSIDE OVR THE NEXT 24 HOURS MAINLY OVR NT2 WTRS AS THE

STGST WINDS CONT TO MOVE E OF THE AREA. THE 12Z MDLS REMAIN

WITHIN A FT OR TWO OF EACH OTHER THRUT THE FCST PD...UNDER THE

RELATIVELY BENIGN WX PTTN. AS A RESULT...PLANNING ON USING A 50/50

BLEND OF THE TWO MDLS AS A COMPROMISE SOLN THRU MON NIGHT BEFORE

PREFERENCE SHIFTS TO 12Z ECMWF WAM.



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



.WARNINGS...PRELIMINARY.



.NT1 NEW ENGLAND WATERS...

     NONE.



.NT2 MID ATLC WATERS...

     NONE.



$$



.FORECASTER BANCROFT. OCEAN PREDICTION CENTER.

