

488 

AGNT40 KWNM 311301

MIMATN



MARINE WEATHER DISCUSSION FOR N ATLANTIC OCEAN

NWS OCEAN PREDICTION CENTER WASHINGTON DC

901 AM 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.



A WARM FRONT CONTS TO DRIFT NE ACRS THE NRN NT2 WTRS THIS MORNING

WITH MAX ASCD WINDS LIKELY IN THE 15-20 KT RANGE...THO IN

CONVECTION FIRING NR 36N LOCAL WINDS ARE LIKELY GUSTING TO GALE

FORCE. MAX SEAS THRUT THE WTRS ARE IN THE 4-6 FT RANGE...HIGHEST

ACRS THE CNTRL NT2 WTRS...WHICH ARE IN LINE WITH THE 06Z WAVEWATCH

III AND 00Z ECMWF WAM MDLS.



OVER THE SHORT TERM...THE LATEST MDLS HV COME INTO BETTER AGRMT IN

REGARDS TO THEIR FCST OF THE WARM FRONT. THE 06Z/00Z GFS...WHICH

YESTERDAY FCST THE WARM FRONT TO LIFT INTO THE NT1 WTRS...NOW

FCST THE FRONT TO BCM QSTNRY FURTHER S ACRS THE NRN NT2 WTRS NR

39N WITH SVRL WEAK LOWS TRACKING E ALONG THE FRONT TONITE THRU

MON NITE...WHICH IS IN BETTER AGRMT WITH THE OTHER FCST MDLS.

THEREFORE WL CONT TO USE THE PREVLY POPULATED 00Z GFS 10M BL

WINDS THRU MON NITE WITH JUST SM MINOR INSIG TWEAKS IN DEFERENCE

TO THE 06Z GFS AND 00Z ECMWF.



IN THE LONG RANGE...AS NOTED IN THE PREV DISCUSSION...THE 00Z

ECMWF (AND THE 00Z GEM) FCST A FINAL AND STRONGER SFC LOW TO

TRACK E ALONG THE FRONT TUE/TUE NITE WITH ASCD BL WINDS FCST TO

APRCH GALE FORCE ACRS THE OUTERMOST NRN NT2 WTRS TUE NITE. THE 00Z

UKMET LOOKS LIKE A SLOW OUTLIER SOLUTION WITH THIS FEATURE. THE

06Z/00Z GFS SHARE SMLR FCST TIMING AS THE 00Z ECMWF BUT FCST

WEAKER SFC LOWS. WITH THE 00Z ECENS MEAN INDICATING THAT THE 00Z

ECMWF MAY BE TOO STRONG WITH ITS FCST LOW...FOR NOW WL CONT TO USE

THE COMPROMISE MIX OF THE WEAKER 12Z ECMWF AND STRONGER 00Z ECMWF

BL WINDS ON TUE THRU WED NITE WITH SM MINOR ADDITIONAL EDITS

MAINLY IN DEFERENCE TO THE 06Z GFS. THEN FURTHER OUT IN THE LONG

RANGE...THU/THU NITE...WITH THE 06Z/00Z GFS AND 00Z ECMWF

SOLUTIONS NOW IN BETTER AGRMT AND SPRTD BY THE 06Z GEFS AND 00Z

ECENS MEANS...WL NOW REPOPULATE WITH ALL 00Z ECMWF BL WINDS AND

00Z ECMWF WAM SEAS THEN WHICH WL RESULT IN GNRLY MINOR CHNGS.









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PREVIOUS DISCUSSION...



SHORT TERM...THE 00Z GLBL MDLS ARE NOW IN GENERALLY GOOD AGREEMENT

OVR THE OFF WTRS INTO EARLY TUE. THE 06Z PRELIM OPC-WPC-NCEP SFC

ANALYSIS SHOWS A STNRY FRONT EXTENDING FROM THE DELMARVA COAST E

OVR NRN NT2 WTRS. LOW PRES WAS LOCATED FURTHER W ALONG THE FRONT

OVR OHIO. THE LATEST SATELLITE IMGRY AND LIGHTNING DENSITY IMGRY

INDICATES STRONG TSTMS INCREASING OFF THE DELMARVA COAST EARLY

THIS MORNING...MOVG OFF TO THE E-NE...MAINLY FROM OFF ZONES

ANZ825 AND 828...TO ANZ925. THE LATEST SREF TSTM GUID SUGGESTS

THAT THESE TSTMS WILL CONT TO SPREAD E-NE INTO THE LATE MORNING

AND AFTN HRS. ADTL TSTMS ARE LKLY OVR MOST OF THE NT2 WTRS DURING

THE NEXT FEW DAYS. LOCAL WIND GUSTS EXCEEDING GALE FORCE...AND

VRY ROUGH SEAS CAN BE FOUND IN OR NR THE STRONGER TSTMS.

OTW...THE LOW WILL DRIFT E OVR THE NEXT DAY OR TWO...AND LKLY

REACH THE SRN JERSEY SHORE THIS EVE OR TONITE...AND THEN SLIDE E

ALONG THE FRONT MON INTO MON NITE. THE FRONT WILL THEN REACH NE

NT2 WTRS TUE EVE. WE WILL REMAIN CLOSE TO THE 00Z GFS 10M WINDS

INTO EARLY TUE. FOR LATER TUE AND TUE NITE...THE 00Z ECMWF IS

DEEPER WITH THE LOW VS THE GFS AND NOW SLOWER THAN THE 12Z ECMWF

IN MOVG THE LOW E OVR THE NRN NT2 WTRS. FOR THE EARLY AM PACKAGE

WE WILL USE A 50-50 BLEND OF THE 00Z ECMWF AND 12Z ECMWF FROM

YESTERDAY FOR LTR TUE AND TUE NITE.



LONG TERM...FOR WED THRU THU NITE WE WILL CONTINUE TO USE A 50-50

BLEND OF THE 00Z ECMWF AND 12Z ECMWF FROM SAT. THIS WILL RESULT

IN ONLY MINOR CHANGES FROM THE PREV FCST. THE LOW WILL CONT TO

DEEPEN AS PUSH E OF THE OFF WTRS WED AS HIGH PRES BUILDS S FROM

NEW ENGLAND. THE HIGH WILL BUILD OVR MOST OF THE WTRS WED NITE

INTO THU NITE AS THE FRONT STALLS OVR THE SRN NT2 WTRS AND

WEAKENS. THE 00Z ECMWF IS MORE PROGRESSIVE IN MOVG THE HIGH E OF

THE WTRS BY LTR THU...WITH THE 12Z CYCLE KEEPING THE HIGH A

LITTLE FURTHER W. A COMPROMISE SOLUTION OF THE 00Z AND 12Z ECMWF

MDLS APPEARS TO BE THE BEST OPTION FOR THE EARLY AM PACKAGE.



SEAS...PER THE LATEST OBS AND ALTIMETER PASS OVR AND NR THE OFF

WTRS THE 00Z WNA WAVE WATCH III AND 00Z ECMWF WAM MDLS APPEAR TO

HAVE INITIALIZED QUITE WELL EARLY THIS MORNING...WITH MAX SEA

HEIGHTS NR 5 FT OVR ERN NT2 WTRS. FOR THE EARLY AM PACKAGE WE

WILL FOLLOW THE ABV DESCRIBED WIND FCST AND REMAIN CLOSE TO THE

00Z WNA WW3 MDL GUID FOR TODAY INTO MON NITE...AND THEN

TRANSITION TO A 50-50 BLEND OF THE 00Z ECMWF WAM AND 12Z SAT

ECMWF WAM WV MDL GUID FOR TUE AND BEYOND. WE WILL ADJUST SEA HTS

DOWN BY 5 PERCENT OR SO FOR LTR TUE THRU THU NITE TO TAKE INTO

ACCT THE OCCASIONAL HIGH BIAS OF THE ECMWF WAM MDL OVR THE WTRS

OR SIMILAR TO WHAT WAS DONE IN THE PREV FEW FCSTS.



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





.WARNINGS...PRELIMINARY.



.NT1 NEW ENGLAND WATERS...

     NONE.



.NT2 MID ATLC WATERS...

     NONE.



$$



.FORECASTER VUKITS/MILLS. OCEAN PREDICTION CENTER.

