

850 

AGNT40 KWNM 241422

MIMATN



MARINE WEATHER DISCUSSION FOR N ATLANTIC OCEAN

NWS OCEAN PREDICTION CENTER WASHINGTON DC

1022 AM EDT WED AUG 24 2016



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

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



GOES IR/VIS IMGRY INDC A WK FRNTL BNDRY JUST E OF THE OFSHR

WTRS...AND HIGH PRES BUILDING OVER THE OFSHR WATERS. THE ASCAT FM

LAST NGT INDC 20 KT BEHIND THE FRONT...BUT CRNT SFC RPRTS INDC

WIND HAVE WEAKENED A LTL WITH THE FRONT MOVG OFF TO THE E...WITH

UP TO 15 KT. THE 06Z GFS INDC ABT THE SAME...AND INDC THE WINDS WL

RMN AT THE INTNSTY OVR SRN NT2 AS HIGH PRES PASSES N OF THE

WATERS. THE REST OF THE 00Z GUID AGREES WELL WITH THE GFS IN THE

SHORT TERM WITH THE MAIN SYNOP FEATURES...SO NOT PLANNING ON MKG

SIG CHANGES FOR THE UPDATE PKG.



OTRW...THE 06Z GFS INDC ANTHR FRNTL BNDRY WL PASS THRU THE NT1

WTRS IN THE THU NGT TO SAT MRNG TIMEFRAME. THE GFS HAS BEEN

CONSISTENT WITH THE TMG AND INTNSTY...AND AGREES WELL WITH THE

THE 00Z MDLS...EXCEPT FOR THE 00Z GEM WHICH HAS CONSISTENTLY BEEN

A PROGRESSIVE OUTLIER. THE ONE POINT OF CONTENTION IS THE SRLY FLW

AHD OF THE FRONT...WHICH THE GFS INDC WL REACH THE 25 KT RNG BY

THU NGT IN THE GULF OF MAINE. CRNT BUOY RPRTS INDC SSTS NR 70 DEG

IN NT1...SO THE NORMALLY SUPPRESSED MIXING IN SW FLOW MAY NOT BE

AS MUCH WITH THE STATIC STABILITIES A LTL LOWER THAN USUAL. THE

PREV FCST HAD 25 KT...SO ATTM PLANNING ON KEEPING IT...WITH LOW TO

MDT CONFDC. OTRW WL BE STAYING NR CONTINUITY FOR THE REMAINDER OF

THE UPDATE PKG.



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

PREVIOUS DISCUSSION...



SUMMARY...00Z NCEP SFC ANALYSIS SHOWS A LARGE HIGH PRES RIDGE

BUILDING E OVER THE OFSHR WTRS...WITH A COLD FRONT E OF THE OFSHR

ZONES EXTDNG IN THE WTRS BETWEEN THE NT2 AREA AND BERMUDA. LATEST

AVAILABLE ASCAT AND ASCAT HI-RES PASSES FROM EARLIER TONITE SHOW

WINDS TO 20 KT IN NE FLOW OVER THE SRN NT2 ZONES AND OVER THE

INNER ZONES NEAR CAPE HATTERAS...BUT ELSEWHERE IN THE OFSHR WTRS

INDICATES ONLY LIGHT WINDS OF 15 KT OR LESS. LIGHTNING DENSITY

PRODUCT DATA AT 0650Z SHOWS A FEW AREAS OF SCATTERED SHOWERS AND

TSTMS JUST S OF THE NT2 AREA...BUT NO ACTIVITY OVER THE OFSHR

WTRS.



MAIN WEATHER FEATURES...THE WEAK SUMMERTIME PATTERN IS EXPCTD TO

CONTINUE THRU THE FCST PERIOD...WITH WINDS NOT EXPCTD TO EXCEED

25 KT. A RIDGE WILL PASS SLOWLY E OVER THE OFSHR WTRS TODAY INTO

FRI. A COLD FRONT WILL APPROACH THE COAST FROM THE NW FRI...THEN

MOVE SE OVER THE OFSHR WTRS FRI NITE INTO SAT NITE WHILE

WEAKENING. ANOTHER RIDGE WILL BUILD SE OVER THE OFSHR WTRS LATE

SAT INTO SUN...THEN PERSIST SUN NITE.



MODELS...THE 00Z MED RNG MDLS ARE IN GUD OVERALL AGREEMNT ACROSS

THE OFSHR WTRS THRU THE FCST PERIOD. THE 00Z GFS 10M SOLN LOOKS

REPRESENTATIVE ENUF TO BE USED FOR THE WIND GRIDS THRU AT LEAST

SUN NITE. AM NOT PLANNING TO MAKE SIGNIF CHANGES TO THE CURRENT

FCST TREND.



SEAS...THE 00Z WNA WAVEWATCH III AND ECMWF WAM BOTH INITIALIZED

WELL OVER THE OFSHR WTRS VERSUS THE RA1 SEA STATE ANALYSIS. THE

MDLS BOTH LOOK REASONABLE AND GENERALLY STAY WITHIN 1 OR 2 FEET

OF EACH OTHER THRU THE ENTIRE FCST PERIOD...SO WILL USE A 50/50

BLEND OF THE 00Z WNA WAVEWATCH III/ECMWF WAM FOR THE WAVE HT

GRIDS AS A COMPRIMISE SOLN.



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



.WARNINGS...PRELIMINARY.



.NT1 NEW ENGLAND WATERS...

     NONE.



.NT2 MID ATLC WATERS...

     NONE.



$$



.FORECASTER KELLS/SCOVIL. OCEAN PREDICTION CENTER.

