

391 

AGNT40 KWNM 010129

MIMATN



MARINE WEATHER DISCUSSION FOR N ATLANTIC OCEAN

NWS OCEAN PREDICTION CENTER WASHINGTON DC

929 PM EDT SUN JUL 31 2016



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

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



THE PRELIM OPC-NCEP 00Z SFC ANALYSIS INDICATES A STNRY FRONT

EXTENDING FROM W TO E OVR NRN NT2 WTRS ROUGHLY ALONG 39N. A 1020

MB HIGH WAS LOCATED N OF THE FRONT NR GEORGES BANK...WITH A 1025

MB HIGH LOCATED ABOUT 425 NM E OF BERMUDA. THE 18Z GFS IS VRY

SIMILAR TO THE 12Z CYCLE WHICH WAS USED FOR THE AFTN FCST

PACKAGE. FOR THE EVE UPDATE WE WILL NOT MAKE SIGNIFICANT CHANGES

TO THE PREV FCST...EXCEPT TO ALTER GRIDS SLIGHTLY TO FIT

CONDITIONS NOTED PRIOR TO FCST ISSUANCE AND TO FIT A LITTLE

BETTER WITH NEARBY WFO AND TAFB FCSTS.



ALSO...THE LATEST SATELLITE AND LIGHTNING DENSITY IMGRY INDICATES

SCTD TSTMS NR THE FRONT...WITH VRY STRONG TSTMS CURRENTLY MOVG

E-NE OVR CENTRAL AND NE NT2 WTRS...OR MORE SPECIFICALLY NRN OFF

ZONE ANZ925 NE INTO ZONE ANZ920. THE LATEST SREF TSTM GUID

INDICATES THAT THIS ACTIVITY WILL PERSIST INTO THE OVERNITE

HRS...WITH ADTL ACTIVITY LKLY THE FRONT THRU MON. LOCAL WIND

GUSTS EXCEEDING GALE FORCE...AND VRY ROUGH SEAS WILL BE LKLY IN

OR NR THE STRONGER TSTMS.



SEAS...SEA HEIGHTS RANGE FROM 2 TO 6 FT OVR THE OFF WTRS PER THE

LATEST OBS AND RA1 SEA STATE ANALYSIS GRAPHIC...WITH THE HIGHEST

SEAS LOCATED OVR NRN NT2 WTRS...AND IN AND NR TSTMS. FOR THE EVE

UPDATE NO MAJOR CHANGES APPEAR NEEDED TO THE PREV FCST.



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

PREVIOUS DISCUSSION...



OVER THE SHORT TERM...THE NEW 12Z MDLS OVERALL REMAIN IN RSNBLY

GOOD AGRMT THAT THE STNRY FRONT NOW ACRS THE NRN NT2 WTRS WL

REMAIN NRLY STNRY TONITE THRU TUE WHILE A SERIES OF LOWS TRACK E

ALONG THE FRONT. THE 12Z GLOBAL MDLS THEN GNRLY AGREE THAT THE

STRONGEST AND FINAL FRONTAL LOW WL PASS E OF THE NT2 WTRS TUE NITE

AND PULL THE FRONT S AS A COLD FRONT ACRS THE CNTRL NT2 WTRS. THE

12Z GEM/ECMWF CONT THEIR PREV RESPECTIVE TRENDS OF FCSTG A

STRONGER FINAL FRONTAL LOW THAN THE 12Z NAM/GFE/UKMET. FOR NOW

SMLR TO THE PREV FCST PACKAGE...PLAN ON POPULATING OUR FCST WIND

GRIDS WITH THE REPRESENTATIVE 12Z GFS 10M BL WINDS FOR TONITE THRU

TUE NITE...WITH SM ADDITIONAL EDITS TO BUMP UP THESE WINDS ACRS

THE FAR SE AND FAR NE NT2 WTRS LATE TUE/TUE NITE IN DEFERENCE TO

THE STRONGER 12Z GEM/ECMWF. SO AS A RESULT ANTICIPATE MAKING ONLY

MINOR SHORT TERM CHNGS TO THE PREV OFSHR FCSTS.



IN THE LONG RANGE...THE 12Z MDLS FCST A QUIET WEATHER PATTERN TO

DVLP. DISREGARDING THE 12Z GEM SOLUTION...OVERALL THE 12Z

GFS/UKMET/ECMWF ARE GNRLY IN GOOD AGRMT THAT THE COLD FRONT WL

CONT S INTO THE SRN NT2 WTRS WED...THEN BCM QSTNRY AND GRADLY

WEAKEN WED NITE INTO FRI WITH WEAK ASCD GRADIENTS AND LITE ASCD

WINDS (GNRLY 10-15 KT OR LESS) DVLPG. THEN LATER FRI/FRI NITE THE

12Z GFS/UKMET/ECMWF ALL FCST A GRADLY STRENGTHENING SSWLY GRADIENT

TO DVLP ACRS THE NRN WTRS AS THE NEXT INLAND COLD FRONT APRCHS FM

THE NW. THEREFORE WL CONT TO POPULATE WITH THE REPRESENTATIVE 12Z

GFS 10M BL WINDS ON WED/WED NITE AND THEN AS A COMPROMISE BTWN

THEIR SMLR SOLUTIONS WL TRANSITION TO A 50/50 BLEND OF THE 12Z GFS

10M AND 12Z ECMWF BL WINDS ON THU THRU FRI NITE.



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

INITIALIZED THE CURRENT SEAS THRUT THE WTRS VERY WELL (GNRLY

WITHIN 1 FT). SO WITH THEIR ASCD GFS/ECMWF SOLUTIONS BEING

SMLR...AND WITH THEIR FCST DIFFERENCES GNRLY RMNG IN THE 1-2 FT

RANGE...WL POPULATE OUR FCST WAVE GRIDS WITH A 50/50 BLEND OF THE

12Z WAVEWATCH III AND 12Z ECMWF WAM MDLS TONITE THRU FRI 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.

