

597 

AGNT40 KWNM 171346

MIMATN



MARINE WEATHER DISCUSSION FOR N ATLANTIC OCEAN

NWS OCEAN PREDICTION CENTER WASHINGTON DC

946 AM EDT WED AUG 17 2016



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

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



12Z WPC/OPC PRELIM SFC ANALYSIS PLACES LOW PRES ALG NE COAST OF

MAINE WITH 1005 MB CENTER WITH TRAILING CODL FRONT SW THRU SRN NEW

ENGLAND AND NRN NJ...WHILE HIGH RES NEAR BERMUDA EXTENDS A RDG W

ACRS CENTRAL AND SRN NT2 WTRS. LATEST SFC OBS SHOW STRONGEST WINDS

AHD OF COLD FRONT IN ERN NT1 ZONES WITH BUOYS SUCH AS 44005 AND

44020 AND ALSO 44027 EARLY THIS MORNING REPORTING GUSTS NEAR 30

KT...BUT OTRW 20 TO 25 KT N OF ABOUT 39N. THESE WINDS ARE CLOSE TO

00Z/06Z GFS 10M WINDS. AS LOW PRES MOVS E INTO MRTMS BY THIS

AFTERNOON EXPECT THE 30 KT WINDS TO BE E OF OFSHR WTRS. LIGHTNING

STRIKE AND DENSITY DATA SHOW LTL ACTVTY...ISOLD NR GLF

STREAM...WITH RADAR DATA SHOWING MAINLY SCT SHRA WITH SOME SHRA

ACTVTY ALSO NEAR CDFNT.



OTRW THE 00Z/06Z GFS/NAM AND OTHER 00Z GLOBAL MDLS AGREE IN SHORT

TERM ON TIMING OF AFOREMENTIONED FRONT AS IT PASSES S THRU RMNDR

OF NT1 WATERS AND INTO NRN NT2 AREA TODAY INTO TONIGHT WHILE THE

HIGH PRES RIDGE PERSISTS OVER THE SRN WATERS. MDLS ALSO AGREE ON

THE NEXT SYSTEM EXPECTED THU NIGHT AND FRI WHICH IS EXPECTED TO BE

WEAKER. THE PREVIOUS FCST FAVORED THE 00Z GFS 10M WINDS SPRTD BY

OTHER GUIDANCE...EXCP NAM BL WINDS LOOK OVERDONE COMPARED TO OBSVD

CONDS. NOT EXPECTING TO MAKE ANY CHANGES IN SHORT RANGE.



IN LONGER RANGE...MDLS ALL AGREE AN UPR RDG WILL BUILD OVER THE

WRN ATLC WITH A FEW WK VORT MAXES PASSING OVR NT2 WTRS ALTHOUGH

MDLS SHOW SOME DISAGREEMENT ON LOCATION AND AND STRENGTH...BUT

MOST MDLS SHOW THEM TO REMAIN WK. THE PREVIOUS FCST STAYED WITH

00Z GFS THRU RMNDR OF FCST PERIOD AND WILL MAINTAIN CONTINUITY AS

RESULT OF MDL DISAGREEMENT ON WK FEATURES REFERRED TO ABOVE. NO

SGFNT COLD ADVECTION IS EXPECTED THRU FCST PERIOD AND 10M GFS

WINDS LOOK REPRESENTATIVE.

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

PREVIOUS DISCUSSION...



CRNT SFC RPRTS INDC SW WINDSUP TO 25 KT OVER THE GULF OF MAINE AND

NW NT1...AHEAD OF A COLD FRONT CRNTLY OVER NEW ENGLAND AND HEADING

TWD THE COAST. THE 23Z RSCAT AND 0140Z ASCAT WIND RETRIEVALS INDC

ABT THE SAME...ALTHO A SMALL AREA OF 30 KT IN THE GULF OF MAINE.

THE WIND ARE FAIRLY STG...CONSIDERING THE SW FLOW OVER THE COLD

SHELF WATERS. THE 00Z GFS 925MB WINDS INDC A STG LL JET...WITH

VALUES UP TO 50 KT...WHICH CREATED VERTICAL SHEAR OVER THE LOWER

WINDS AT THE SFC. ALSO...THE 00Z GFS INDC A JET STREAK OVER THE W

ATLC...WITH THE RIGHT ENTRANCE REGION OVER THE GULF OF MAINE. THE

ENHANCEMENTS HAVE HELPED WITH MIXING STGR WIND ALOFT TO THE

SFC...AS SHOWN BY CRNT RPRTS AND THE ASCAT DATA. THE 00Z GFS 10M

WINDS INDC UP TO 30 KT IN THE GULF OF MAINE...AND ARE INIT WELL IN

THE OFSHR WTRS. THE 00Z ECWMF/UKMET/GEM/NAM AGREE WELL WITH THE

TMG AND INTNSTY OF THE FRONT...AND INDC THE LOW WL PULL THE FRONT

THRU THE OFSHR WATERS TDA INTO TNGT. THE PREV FCST CAPPED WINDS AT

25 KT...SO PLANNING ON INCSRG TO 30 KT IN THE NEXT FCST...MAINED

BASED ON CRNT DATA. 



OTRW...THE 00Z MDLS AGREE IN THE SHORT TERM...AND THE 00Z

GFS/ECMWF ARE IN RSNBLY GUD AGRMT THRUT THE RMEAINDER OF THE FCST

PD. THE MDLS INDC ANOTHER WK COLD FRONT WL PASS THRU NT1 THU

NGT...THO THE WINDS ARE XPCTD TO STAY WKR THAN THE CRNT BNDRY...AS

THE UPPER WINDS ARE NOT AS STG AS THOSE ASSOC WITH THE CRNT FRONT.

THE 00Z MDLS THEN INDC AN UPPER RDG WL BUILD OVER THE W ATLC FRI

NGT INTO SUN NGT...AS A FEW WK H5 VORTS MV OVR NT2. THERE HAS BEEN

A FEW SLIGHT DIFFS ON THE VORT MAXES...WHICH DVLP WK LOWS ALONG

THE AFOREMENTIONED FRONTAL BNDRY AS IT SAGS INTO C NT2.

HOWEVER...WINDS ARE XPCTD TO RMN LGT IN THE OFSHR WATERS...SO

WARNINGS ARE NOT A CONCERN FOR THE NEXT PKG. THE PREV FCST

FAVORED THE GFS...AND ATTM IT CONTINUES TO BE WELL SUPPORTED BY

THE REST OF THE 00Z GUID...SO PLANNING ON FAVORING THE 00Z GFS FOR

THE NEXT FCST PKG. 



.SEAS...BUOY REPORTS IN THE GULF OF MAINE INDC SEAS TO 7 FT CRNTLY

IN THE SW FLOW AHD OF THE APRCHG CD FRONT. THE 00Z NWW3 AND ECMWF

WAM MDLS ARE INITALIZED WELL WHEN COMPARED WITH THE DATA...AND

INDC THE HIGHER SEAS WL MOVE OFF TO THE EAST WITH THE HIGHER WINDS

TDA INTO TNGT. THE MDLS AGREE VERY WEL IN THE SHORT TERM...THEN

DIFFER SLIGHTLY IN THE EXTENDED PD. ATTM PLANNING ON USING A 50/50

BLEND OF THE TWO SOLNS...AS A COMPROMISE SOLN.



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



.WARNINGS...PRELIMINARY.



.NT1 NEW ENGLAND WATERS...

     NONE.



.NT2 MID ATLC WATERS...

     NONE.



$$



.FORECASTER BANCROFT/KELLS. OCEAN PREDICTION CENTER.

