

843 

AGNT40 KWNM 021418

MIMATN



MARINE WEATHER DISCUSSION FOR N ATLANTIC OCEAN 

NWS OCEAN PREDICTION CENTER WASHINGTON DC

1015 AM EDT FRI 2 SEP 2016 



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

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



THE TROPICAL STORM FORCE WINDS HAVE MOVED OFFSHORE OF THE 

GEORGIA COAST THIS MORNING AS BUOY 41008 SE OF SAVANNAH HAD A 37 

G 47 KT REPORT AT 12Z. THE 00Z/06Z GFS AND 00Z ECMWF BOTH 

TRENDED SIGNIFICANTLY STRONGER WITH HERMINE SAT THROUGH SUN 

NIGHT WHEN IT IS FORECAST TO BECOME POST-TROPICAL. THESE MODELS 

ALSO INDICATE THAT HERMINE COULD AGAIN ACQUIRE TROPICAL 

CHARACTERISTICS AT THAT TIME. THIS SIGNIFICANT DEEPENING IS NOT 

UNREASONABLE AS SYSTEM IS FORECAST TO SLOWLY MOVE ACROSS THE THE 

GULF STREAM WHERE SST ANOMALIES ARE ON THE ORDER OF +3 TO +5 C 

AND WITH THE DEVELOPING BAROCLINICITY OVER THE SW SEMICIRCLE OF 

SYSTEM. SO HAVE SOME CONCERN THAT WINDS MAY BE STRONGER THAN 

CURRENTLY FORECAST AND WILL MONITOR TODAYS MODEL TREND. THE 

00Z/06Z WAVEWATCH III AND 00Z ECMWF WAM ARE BOTH WELL INITIALIZD 

WITH OFFSHORE/COASTAL WAVE HEIGHTS THIS MORNING. 



NHC KEY MESSAGE:



1. HERMINE IS EXPECTED TO BECOME A POST-TROPICAL CYCLONE WHILE

STILL PRODUCING HAZARDOUS WINDS AND STORM SURGE OVER LAND.  NWS

POLICY ALLOWS NHC TO WRITE ADVISORIES ON AND ISSUE TROPICAL STORM

WATCHES AND WARNINGS FOR POST-TROPICAL CYCLONES, WHEN THE SYSTEM

CONTINUES TO POSE A SIGNIFICANT THREAT TO LIFE AND PROPERTY. NHC 

AND THE NWS EASTERN REGION HAVE DECIDED THAT THIS OPTION WILL BE 

INVOKED FOR HERMINE.  AFTER HERMINE BECOMES A POST-TROPICAL 

CYCLONE, NHC WILL CONTINUE TO ISSUE ITS FULL SUITE OF ADVISORY 

AND WARNING PRODUCTS FOR AS LONG AS THE SYSTEM REMAINS A 

SIGNIFICANT THREAT TO LAND.



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

...PREVIOUS DISCUSSION...



NOTE: OPC IS PROVIDING POST-TROPICAL FORECAST SUPPORT TO NHC FOR 

HURRICANES GASTON AND HERMINE...SO THIS DISCUSSION WILL BE 

BRIEF. 

IN REGARDS TO FCST TRACK OF HERMINE...THE NEW 00Z MDLS ARE ALL 

IN RSNBLY GOOD AGRMT THAT THE SYSTEM WL TRACK NE TO NEAR OF JUST 

INLAND ALONG THE S THEN N CAROLINA COASTS BY LATE TODAY INTO 

TONITE...THEN MOVE NE OFF THE N CAROLINA COAST SAT TO THE VCNTY 

OF 36.5N 72.5W BY 04/00Z. AT THIS TIME THE 00Z GEFS MEAN 

INDICATES THAT THE 00Z GFS 48HR POSITION MAY BE TOO FAR E WHICH 

IS ALSO INDICATED BY THE 00Z ECMWF. THEN AS THE SYSTEM IS FCST 

TO GET CAPTURED BY A CLOSED UPR LOW...TO VARYING DEGREES THE 00Z 

MDLS ALL FCST THE SYSTEM TO PERFORM A TIGHT CYCLONIC LOOP SAT 

NITE INTO SUN NITE (WITH THE 00Z GEM/UKMET SWINGING THEIR LOW 

FURTHER E THAN THE 00Z GFS)...BCM QSTNRY MON INTO MON NITE IN 

THE VCNTY OF 39N 71.5W...THEN DRIFT SLOWLY ENE TUE/TUE NITE (THO 

THE 00Z GFS FCSTS ITS LOW TO BCM QSTNRY FURTHER W THAN THE OTHER 

00Z GLOBAL MDLS WHICH PER THE 00Z GEFS MEAN MAY BE TOO FAR W). 

FOR NOW IF FORCE TO CHOOSE WULD FAVOR A BLENDED 00Z GEFS 

MEAN/ECMWF TRACK THRU SAT NITE. THEN WOULD FAVOR A COMPROMISE 

00Z GFS/ECMWF TRACK FOR SUN INTO TUE NITE AS THE DIFFERENCES 

BTWN THEIR FCST TRACKS NARROW. SO AGAIN DUE TO THE SLOW EXPECTED 

MOVEMENT OF HERMINE AS IT TRACKS INTO THE NT2 WTRS...DO NOT 

EXPECT NHC TO MAKE ANY MAJOR CHNGS IN THEIR NEXT FCST ADVSRY. 



.SEAS...THE 00Z WAVEWATCH III AND 00Z ECMWF WAM HV BOTH 

INITIALIZED THE CURRENT SEAS WELL...THO THE SLIGHTLY LOWER 00Z 

WAVEWATCH III LOOKS SLIGHTLY BETTER AT THE MOMENT. DEPENDING ON 

THE NEXT NHC ADVSRY AM LEANING AT THE MOMENT OF POPULATING WITH 

A 50/50 BLEND OF THE TWO WAVE MDLS THRU TUE NITE. 



.EXTRATROPICAL STORM SURGE GUIDANCE...WITH ALL OF THE 00Z MODELS 

FCSTG HERMINE TO SLOW AND NEARLY STALL OFF THE NRN MID ATLC AND 

SRN NEW ENGLAND COASTS SUN INTO TUE...THERE IS A HIGH LIKLIHOOD 

THAT A SIGNIFICANT SURGE EVENT WILL DEVELOP. WULD CONT TO FAVOR 

THE HIGHER SURGE VALUES FCST BY THE 00Z ESTOFS VS THE 00Z ETSS 

THEN. 



.WARNINGS...PRELIMINARY. 



.NT1 NEW ENGLAND WATERS...

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

     TROPICAL STORM POSSIBLE SUN INTO TUE NIGHT. 

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

     TROPICAL STORM SAT NIGHT.

     TROPICAL STORM POSSIBLE SUN INTO TUE NIGHT. 



.NT2 MID ATLC WATERS...

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

     TROPICAL STORM SAT INTO SAT NIGHT. 

     TROPICAL STORM POSSIBLE SUN INTO SUN NIGHT. 

     HURRICANE POSSIBLE MON.

     TROPICAL STORM POSSIBLE MON NIGHT INTO TUE NIGHT. 

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

     TROPICAL STORM SAT INTO SAT NIGHT. 

     TROPICAL STORM POSSIBLE SUN.

     HURRICANE POSSIBLE SUN NIGHT INTO MON. 

     TROPICAL STORM POSSIBLE MON NIGHT INTO TUE NIGHT. 

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

     TROPICAL STORM SAT INTO SAT NIGHT. 

     TROPICAL STORM POSSIBLE SUN.

     HURRICANE POSSIBLE SUN NIGHT INTO MON. 

     TROPICAL STORM POSSIBLE MON NIGHT INTO TUE NIGHT. 

.ANZ825...INNER WATERS FROM BALTIMORE CANYON TO CAPE CHARLES 

LIGHT...

     TROPICAL STORM TONIGHT INTO SAT NIGHT. 

     TROPICAL STORM POSSIBLE SUN INTO TUE. 

.ANZ828...INNER WATERS FROM CAPE CHARLES LIGHT TO CURRITUCK 

BEACH LIGHT...

     TROPICAL STORM TONIGHT INTO SAT NIGHT. 

     TROPICAL STORM POSSIBLE SUN INTO MON. 

.ANZ925...OUTER WATERS FROM BALTIMORE CANYON TO HATTERAS 

CANYON...

     TROPICAL STORM SAT INTO SAT NIGHT. 

     TROPICAL STORM POSSIBLE SUN.

     HURRICANE POSSIBLE SUN NIGHT INTO MON. 

     TROPICAL STORM POSSIBLE MON NIGHT INTO TUE. 

.ANZ830...INNER WATERS FROM CURRITUCK BEACH LIGHT TO CAPE 

HATTERAS...

     TROPICAL STORM TONIGHT INTO SAT NIGHT. 

     TROPICAL STORM POSSIBLE SUN.

.ANZ833...INNER WATERS FROM CAPE HATTERAS TO CAPE FEAR...

     TROPICAL STORM TONIGHT INTO SAT NIGHT. 

.ANZ930...OUTER WATERS FROM HATTERAS CANYON TO CAPE FEAR...

     TROPICAL STORM TONIGHT INTO SAT NIGHT. 

     TROPICAL STORM POSSIBLE SUN.

.ANZ835...INNER WATERS FROM CAPE FEAR TO 31N...

     TROPICAL STORM TODAY INTO TONIGHT. 



$$ 



.FORECASTER CLARK. OCEAN PREDICTION CENTER.

