

925 

AGNT40 KWNM 300109

MIMATN



MARINE WEATHER DISCUSSION FOR N ATLANTIC OCEAN

NWS OCEAN PREDICTION CENTER WASHINGTON DC

909 PM EDT FRI JUL 29 2016



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

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



1008 MB LOW PRES IS LOCATED ABOUT 100 NM SE OF NANTUCKET ISLAND

PER THE 00Z PRELIM OPC-NCEP SFC ANALYSIS. A STNRY FRONT EXTENDS

E-NE FROM THE LOW WITH A COLD FRONT EXTENDING SW FROM THE LOW

TOWARD CAPE HATTERAS. THE LOW WILL TRACK E-NE AWAY FROM THE WTRS

OVERNITE...WITH THE FRONT DRIFTING SOUTHWARD. THE FRONT IS STILL

FCST TO BECOME NEARLY STNRY DURING THE DAY SAT...WITH A SERIES OF

WEAK LOWS TRACKING ALONG THE FRONT LTR SAT INTO NEXT WK.



OVERALL...THE 18Z GFS AND NAM MDLS SUGGEST THAT LITTLE CHANGE WILL

BE NEEDED TO THE PREV FCST FOR THE EVE UPDATE. THE LATEST

SATELLITE...RADAR... AND LIGHTNING DENSITY DATA INDICATES SCTD

TSTMS ALONG THE FRONT EXTENDING FROM GEORGES BANK SW TO NEAR CAPE

HATTERAS. LOCAL WIND GUSTS EXCEEDING GALE FORCE MAY OCCUR WITH

THE HEAVIER TSTMS ALONG WITH VRY ROUGH SEAS TONITE MAINLY NR THE

ABOVE MENTION LOW AND COLD FRONT. THE LATEST SREF TSTMS GUID

SUGGEST THAT THIS TSTM ACTIVITY WILL SHIFT A LITTLE SOUTHWARD

WITH THE FRONT TONITE INTO SAT...AND THEN POTENTIALLY INCREASE

AND EXPAND SAT AFTN AND NITE AS THE FIRST IN A SERIES OF WK LOW

PRES AREAS PASS E ALONG THE FRONT. OVERALL...WE WILL DO NOT PLAN

ON MAKING SIGNIFICANT CHANGES TO THE ONGOING FCST FOR THE EVE

UPDATE.



SEAS...SEA HEIGHTS RANGE FROM 6 FT OVR NRN AND CENTRAL NT2 WTRS TO

1 TO 2 FT OVR THE GULF OF MAINE PER THE LATEST OBS AND 00Z RA1 OPC

SEA STATE ANALYSIS GRAPHIC. AGAIN...LITTLE CHANGE TO THE ONGOING

OPC FCST APPEARS NEEDED FOR THE EVE UPDATE.



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

PREVIOUS DISCUSSION...



OVER THE SHORT TERM...THE NEW 12Z MDLS ARE IN RSNBLY GOOD AGRMT

THAT THE SFC LOW NOW SE OF LONG ISLAND...WITH MAX ASCD WINDS

GNRLY IN THE 20-25 KT RANGE...WL TRACK NE ACRS THE FAR SE NT1 WTRS

EARLY TONITE...THEN ACCELERATE OFF TO THE E OF THE NT1 WTRS LATER

TONITE WHILE PULLING A TRAILING COLD FRONT S INTO THE NRN NT2 WTRS

WITH THE STRONGEST ASCD WINDS BCMG SE OF THE FRONT ACRS THE

OUTERMOST NRN/CNTRL NT2 WTRS. THEN WITH SLIGHT TIMING

DIFFERENCES...THE 12Z MDLS FCST THE FRONT TO BCM QSTNRY ACRS THE N

CNTRL NT2 WTRS SAT...THEN SLOWLY RETURN NWD AS A WARM FRONT SAT

NITE INTO SUN NITE. BY FCSTG A MR PRONOUNCED FRONTAL LOW(S?) TO

DVLP ALONG THE FRONT SUN/SUN NITE THE 12Z NAM/GFS/GEM DO NOT FCST

THEIR WARM FRONTS TO LIFT AS FAR N AS THE 12Z UKMET/ECMWF...THO

THE 12Z ECMWF IS NOW FURTHER S THAN ITS PREV 00Z RUN CLOSER TO THE

12Z GFS. SO WITH THIS IN MIND PLAN ON POPULATING OUR SHORT TERM

FCST WIND GRIDS WITH THE 12Z GFS 10M BL WINDS FOR TONITE THRU SUN

NITE...WITH SM MINOR ADDITIONAL EDITS IN DEFERENCE TO THE 12Z

UKMET/ECMWF.



IN THE LONG RANGE...THE 12Z GFS REMAINS VERY CONSISTENT VS ITS

PREV RESPECTIVE RUNS IN FCSTG THE FRONT TO BCM QSTNRY ACRS THE

NRN/CNTRL NT2 WTRS MON THRU TUE WHL SVRL WEAK FRONTAL WAVES TRACK

E ACRS THE WTRS...WITH THE FINAL FRONTAL LOW THEN PULLING THE

FRONT SLOWLY S INTO THE CNTRL/SRN NT2 WTRS TUE NITE INTO WED NITE.

OVERALL THE 12Z GEFS MEAN SUPPORTS THIS 12Z GFS SOLUTION. THO THEY

START WITH THEIR FRONTS FARTHER S MON INTO TUE...BY TUE NITE/WED

THE OTHER 12Z GLOBAL MDLS COME INTO BETTER AGRMT WITH THE 12Z GFS

FROPA. MAINLY TO BE MR IN LINE WITH THE LATEST WPC MEDIUM RANGE

GUIDANCE WL CONT TO POPULATE WITH THE 12Z GFS 10M BL WINDS ON MON

THRU TUE. THEN AS THEIR SOLUTIONS COME INTO BETTER AGRMT AND AS A

COMPROMISE...WL THEN TRANSITION TO POPULATING WITH A 50/50 BLEND

OF THE 12Z GFS 10M AND 12Z ECMWF BL WINDS FOR TUE NITE THRU WED

NITE.



.SEAS...THE 12Z WAVEWATCH III AND 12Z ECMWF WAM HV BOTH

INITIALIZED THE CURRENT SEAS RSNBL WELL. BUT SINCE THE 12Z GFS WL

BE FAVORED...WL POPULATE OUR FCST WAVE GRIDS WITH THE 12Z

WAVEWATCH III FOR TONITE THRU TUE. THEN SINCE A BLENDED 12Z

GFS/ECMWF SOLUTION WL BCM FAVORED...WITH THEN TRANSITION TO

POPULATING WITH A 50/50 BLEND OF THE 12Z WAVEWATCH III AND 12Z

ECMWF WAM FOR TUE NITE THRU WED NITE.



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





.WARNINGS...PRELIMINARY.



.NT1 NEW ENGLAND WATERS...

     NONE.



.NT2 MID ATLC WATERS...

     NONE.



$$



.FORECASTER MILLS/VUKITS. OCEAN PREDICTION CENTER.

