

634 

AGNT40 KWNM 051445

MIMATN



MARINE WEATHER DISCUSSION FOR N ATLANTIC OCEAN

NWS OCEAN PREDICTION CENTER WASHINGTON DC

1045 AM EDT MON SEP 5 2016



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

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



GOES VIS IMGRY INDC POST-TROPICAL CYCLONE HERMINE IN THE NRN NT2

WATERS...WITH STG N TO NE FLOW W AND NW OF THE CENTER. ASCAT FM

01Z LAST NGT INDC A LARGE AREA OF 50 KT INVOF THE N WALL OF

THE GULF STREAM. CRNT SFC RPRTS INDC WINDS UP TO 45 KT NEAR THE

LOW CENTER...WITH 45 KT IN GEORGES BANK. THE 06Z GFS IS

INITIALIZED WELL WITH THE WINDS...INDICATING 55 TO 60 KT W AND NW

OF THE LOW...IN THE REGION TO THE W OF THE BENT-BACK OCCLUSION.

THE GLOBAL MODELS HAVE BEEN RUNNING W OF THE PREV FCST. WITH THE

LEFT EXIT REGION OF AN H2 JET STREAK W OF THE LOW CENTER...AND

SOME MDT MID LEVEL FORCING TO THE W OF THE CENTER...A W TRACK

SEEMS LIKE A RSNBL SOLN. THE LTST GEFS/ECMWF MEAN SOLNS AND

INDIVIDUAL MEMEBERS ARE CLUSTERED NR THE OPERATION SOLNS...SO

THE W TRACK HAS CONSIDERABLE SUPPORT. THIS MATCHES WITH THE WL BE

USING NHCS NEXT ADVISORY FOR THE UPDATE PKG. OTRW WL NOT BE MAKING

SIG CHANGES FOR THE REMAINDER OF THE FCST PD.



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

PREVIOUS DISCUSSION...



THE SAT IMG STILL INDC THAT POST-TROIPICAL CYCLONE HERMINE IS

OVER THE ERN PARTS OF THE CENTRAL WATERS WHILE A HIGH PRES RIDGE

IS OVER THE FAR NRN PARTS AND OVER THE S-WRN PARTS. THE LATEST

OBSERVATIONS INCLUDING THE ASCAT PASS AT SHOW HIGHER WINDS OVER

THE CENTRAL WATERS. A SHIP NOW LOCATED NEAR 40N 68W REPORTED NE

WINDS 45 KT AT 06Z. THE 06Z NCEP MAP STILL HAS POST-TROPICAL

CYCLONE HERMINE OVER ZONE ANZ910 WITH A SERIES OF HIGH PRES

CENTERS TO THE N AND A RIDGE STRETCHING FROM HIGH PRES CENTER 1029

MB NEAR 44N58W THRU THE FAR NRN WATERS TO THE GREAT LAKES AND

BEYOND. THE PRES GRDIENT IS STILL VERY TIGHT OVER THE CENTRAL

WATERS BUT VERY RELAXED OVER THE SRN AND FAR NRN WATERS.



THE GLOBAL MODELS HAVE INITIALIZED FAIRLY WELL WITH THE 06Z

OBSERVATIONS BUT STILL HAVE DIFFERENCES ON THE MAX WINDS. GFS HAS

ITS STRONGEST WINDS IN THE NW SECTOR WHILE THE ECMWFHR HAS THAT IN

THE N SECTOR AND THAT THE ECMWFHR WINDS ARE LOWER THAN GFS. THE

CMC WINDS ARE HIGH IN BOTH THE N AND NW SECTORS AND ARE ABOUT THE

SAME AS MAGNITUDE AS THE GFS AND THE UKMETHR WINDS ARE AS WEAK AS

THE ECMWFHR AND ITS COVERAGE OF HIGHER WINDS IS SIMILAR TO THE

CMC. DIFFERENCES IN WINDS AREAL COVERAGE AND MAGNITUDE ARE SIMILAR

THRU THE SHORT TERM BUT THESE DIFERENCES ARE LESS IN THE EXTENDED

PERIOD AS HERMINE WEAKENS AND MOVES TWD NE. GFS/ECMWFHR/UKMETHR

SUGGEST THAT HERMNE WILL MOVE NE AS IT WEAKENS AND WILL EITHER GET

ABSORBED OR JUST DISSIPATE IN THE EXTENDED PERIOD. THE ECMWFHR HAS

THE SYSTEM MORE N WHILE UKMETHR AND GFS ARE MUCH CLOSER TO THE

PREVIOUS SOLUTION. MODELS INDC THAT MOST OF THE SRN HALF WILL HAVE

A VERY RELAXED PRES GRADIENT AND WINDS WILL REMAIN BELOW WARNING

THRESHOLD THRU MOST OF THE PERIOD.



.SEAS...THE SEAS STILL HAVE 30 FT PEAKS OVER THE CENTRAL WATERS

AND THEY CONTINUE TO RANGE BETWEEN 5 AND 12 FT OVER MOST OF THE

WATERS OUTSIDE THE WARNING AREA. SEAS ARE EVEN SMALLER LESS THAN 6

FT AT THE FAR NRN AND FAR S-WRN WATERS. NWW3 WAVE MODEL FITS WELL

WITH THE 06Z OBSERVED SEAS PATTERN BUT IS STILL UNDERDONE ON THE

PEAK VALUE BY 6 FT. THE ECMWFWAVE ALSO FITS WELL WITH THE SEAS

PATTERN BUT IS EQUALLY UNDERDONE ON THE PEAK VALUE. WILL STILL

CONTINUE TO USE THE NWW3 BUT WILL HAVE TO STILL MAKE SOME MINOR

ADJUSTMENTS TO MATCH THE PEAK VALUES NEAR HERMINE.





.EXTRATROPICAL STORM SURGE GUIDANCE...WITH MODELS FORECASTING HERMINE 

TO HAVE A SLOW MEANDERING N AND THEN NE MOTION OFF THE NRN MID

ATLC AND SRN NEW ENGLAND COASTS THROUGH AT LEAST WED...STORM SURGE

WILL CONTINUE TO IMPACT THE COAST FROM THE DELMARVA PENINSULA TO

LONG ISLAND THROUGH EARLY THIS WEEK. FOR FURTHER DETAILS AND

GUIDANCE PLEASE SEE THE STORM SURGE SECTION OF THE NHC PUBLIC

ADVISORY AND THE NHC PROTOTYPE STORM SURGE WATCH/WARNING GRAPHIC

AT: WWW.HURRICANES.GOV/GRAPHICS_AT4.SHTML?WSURGE (ALL LOWERCASE).

ALSO SEE THE NHC KEY MESSAGES CONCERNING STORM SURGE BELOW.



NHC KEY MESSAGES (FROM 11AM NHC ADVISORY):



1. THE SLOW MOTION AND LARGE WIND FIELD ASSOCIATED WITH HERMINE

WILL RESULT IN A LONG DURATION OF HAZARDOUS CONDITIONS ALONG MUCH

OF THE MID-ATLANTIC COAST EXTENDING INTO SOUTHERN NEW ENGLAND

THROUGH THE HOLIDAY WEEKEND AND INTO MIDWEEK.



2. TROPCIAL STORM CONDITIONS WILL SPREAD NORTHWARD WITHIN THE

WARNING AREA ALONG THE ATLANTIC COAST THROUGH MON. TROPICAL STORM

CONDITIONS ARE POSSIBLE IN THE WATCH AREA BY MON.



3. THERE IS A DANGER OF LIFE-THREATENING INUNDATION WITHIN THE

NEXT 36 HOURS FROM CAPE CHARLES, VIRGINIA, TO SANDY HOOK, NEW

JERSEY. THERE IS ALSO THE POSSIBILITY OF LIFE-THREATENING

INUNDATION DURING THE NEXT 48 HOURS AT NAMY COASTAL LOCATIONS

BETWEEN SANDY HOOK, NEW JERSEY AND BRIDGEPORT, CONNECTICUT,

INCLUDING LONG ISLAND.



4. ALTHOUGH HERMINE HAS BECOME A POST-TROPICAL CYCLONE, NHC WILL

CONTINUE TO ISSUE ITS FULL SUITE OF ADVISORY AND WARNING PRODUCTS

AS LONG AS THE SYSTEM REMAINS A SIGNIFICANT THREAT TO LAND AREAS.



.WARNINGS...PRELIMINARY.



.NT1 NEW ENGLAND WATERS...

.ANZ805...GEORGES BANK WEST OF 68W...

     TROPICAL STORM TODAY INTO TUE NIGHT. 

     TROPICAL STORM POSSIBLE WED INTO THU. 

.ANZ900...GEORGES BANK EAST OF 68W...

     TROPICAL STORM TODAY INTO TUE. 

     TROPICAL STORM POSSIBLE THU.

.ANZ810...SOUTH OF NEW ENGLAND...

     TROPICAL STORM TODAY INTO TUE NIGHT. 

     TROPICAL STORM POSSIBLE WED INTO THU. 

.ANZ815...SOUTH OF LONG ISLAND...

     TROPICAL STORM TODAY INTO TUE NIGHT. 

     TROPICAL STORM POSSIBLE WED INTO WED NIGHT. 



.NT2 MID ATLC WATERS...

.ANZ820...HUDSON CANYON TO BALTIMORE CANYON...

     TROPICAL STORM TODAY INTO TUE NIGHT. 

.ANZ915...HUDSON CANYON TO THE GREAT SOUTH CHANNEL...

     TROPICAL STORM TODAY INTO TUE NIGHT. 

     TROPICAL STORM POSSIBLE WED INTO WED NIGHT. 

.ANZ920...BALTIMORE CANYON TO THE GREAT SOUTH CHANNEL...

     TROPICAL STORM TODAY INTO TUE NIGHT. 

.ANZ905...THE GREAT SOUTH CHANNEL TO THE HAGUE LINE...

     TROPICAL STORM TODAY INTO TUE NIGHT. 

     TROPICAL STORM POSSIBLE WED.

.ANZ910...EAST OF THE GREAT SOUTH CHANNEL AND SOUTH OF 39N...

     TROPICAL STORM TODAY.

     TROPICAL STORM TUE.



$$



.FORECASTER KELLS/MUSONDA. OCEAN PREDICTION CENTER.

