

548 

AGNT40 KWNM 042042

MIMATN



MARINE WEATHER DISCUSSION FOR N ATLANTIC OCEAN 

NWS OCEAN PREDICTION CENTER WASHINGTON DC

430 PM EDT SUN 4 SEP 2016 



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

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



THIS MORNINGS ASCAT OVERPASSES MISSED CENTER OF HERMINE AS WELL 

AS THE HIGHEST WINDS. HOWEVER THE EDGE OF THE 1430Z PASS 

SUGGESTED THAT GALES OVER THE W QUADRANT OF HERMINE EXTEND 

SLIGHLY FURTHER W THAN INITIALIZED BY THE 12Z MODELS. ALSO THE 

GALES N OF THE WARM FRONT EXTENDED AS FAR E AS 63W. OVER THE 

NEAR TERM THE 12Z MODELS ARE IN GOOD AGREEMENT THAT HERMINE 

SHOULD DEEPEN OVER THE NEXT 12 TO 24 HOURS...WITH THE MODEL 

CONSENSUS ON ORDER OF 7 TO 10 MB...AT WHICH TIME SHOULD SEE A 

SLIGHT INCREASE IN WINDS TO HURCN FORCE. AS FAR AS THE TRACK 

MODELS CONTINUE TO HAVE DIFFICULTY AND SHOW LITTLE RUN TO RUN 

CONSISTENCY. THE 12Z ECMWF MOVES THE SYSTEM WITHIN MUCH FURTHER 

N AND WITHIN 30 NM OF NANTUCKET AND CAPE COD...ALTHOUGH AS A 

WEAKER SYSTEM THAN SHOWN BY PREVIOUS RUNS. OVER PAST DAY OR SO 

MODELS HAVE GENERALLY TRENDED WEAKER WITH HERMINE FROM TUE 

ONWARD. HOWEVER THE 12Z GFS BUCKED THIS TREND AND NOW INDICATES 

WINDS UP TO 50 OR 55 KT AS HERMINE TRACKS NE NEAR GEORGES BANK 

AND S OF THE CANADIAN MARITIMES. IF THE NEXT NHC ADVISORY 

REMAINS CONSISTENT AND IS STRONGER LIKE THE 12Z GFS...WILL BE 

ABLE TO BETTER UTILIZE THE 12Z WAVEWATCH III FOR WAVE HEIGHT 

GRIDS AT LATE TUE THROUGH THU. 



THE 12Z MODELS CONTINUED TO SHOW SIGNIFICANT TIMING DIFFERENCES 

FROM LATE MON NIGHT THROUGH THU NIGHT WITH THE ECMWF STILL A 

FULL TWO DAYS FASTER THAN GFS/UKMET IN WEAKENING THE UPPER LOW 

AND THEN EJECTING THE OPEN TROUGH NE OF GEORGES BANK. THE 

PREVIOUS NHC FORECAST RELIED ON A COMPROMISE BETWEEN THE GFS AND 

ECMWF. AM NOT ANTICIPATING THAT THERE WILL BE MAJOR CHANGES WITH 

NEXT NHC ADVISORY...AND AS A RESULT WILL NOT BE MUCH CHANGE IN 

THE WARNINGS FROM THE PREVIOUS NT1/NT2 FORECASTS. FORECAST 

CONFIDENCE REMAINS WELL BELOW AVERAGE AFTER ABOUT 24 TO 36 

HOURS. SURPRISINGLY BY LATE FRI/FRI NIGHT THE GFS AND ECMWF ARE 

IN DECENT AGREEMENT IN MOVING A WEAK COLD FRONT OFF THE NEW 

ENGLAND COAST.   



SEAS...LAST EVENINGS ASCAT OVERPASS RETURNED 50 TO 55 KT ACROSS 

THE GULF STREAM FROM ABOUT 36.5N TO 38N...JUST NW OF THE 

OCCLUDED FRONT. WITH HERMINE FORECAST TO SLOWLY MEANDER N THE 

STRONGEST N TO NE WINDS WILL CONTINUE TO BE COUNTERFLOW TO THE 

GULF STREAM TONIGHT INTO EARLY TOMORROW CREATING A PERILOUS SEA 

STATE NEAR THE STREAM. WE BELIEVE THE HIGHER ECMWF WAM HAS A 

MUCH BETTER HANDLE THAN THE WAVEWATCH III WITH WAVE HEIGHTS THIS 

AFTERNOON.  1445Z CRYOSAT AND 16Z JASON-2/3 ALTIMETER OVERPASSES 

RETURNED 20 TO 27 FT ACROSS THE GULF STEAM AND WAVE HEIGHTS ARE 

LIKLEY SOMEWHAT HIGHER BETWEEN THESE TWO OVERPASSES. GRIDS WILL 

LIKELY AGAIN NEED A GREAT DEAL OF MANUAL EDITS TO ADJUST FOR THE 

TIMING AND INTENSITY FORECAST FROM NHC.  



.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. 

     TROPICAL STORM POSSIBLE TUE NIGHT INTO WED NIGHT. 

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

     TROPICAL STORM TONIGHT INTO TUE. 

     TROPICAL STORM POSSIBLE TUE NIGHT INTO THU. 

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

     TROPICAL STORM TODAY INTO TUE. 

     TROPICAL STORM POSSIBLE TUE NIGHT INTO WED NIGHT. 

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

     TROPICAL STORM TONIGHT INTO TUE. 

     TROPICAL STORM POSSIBLE TUE NIGHT INTO WED. 



.NT2 MID ATLC WATERS...

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

     TROPICAL STORM TONIGHT INTO TUE. 

     TROPICAL STORM POSSIBLE TUE NIGHT.

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

     TROPICAL STORM TODAY INTO TUE. 

     TROPICAL STORM POSSIBLE TUE NIGHT INTO WED NIGHT. 

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

     TROPICAL STORM TODAY INTO TUE. 

     TROPICAL STORM POSSIBLE TUE NIGHT.

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

     TROPICAL STORM TODAY INTO TUE. 

     TROPICAL STORM POSSIBLE TUE NIGHT INTO THU. 

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

     TROPICAL STORM TODAY INTO TUE. 

     TROPICAL STORM POSSIBLE TUE NIGHT INTO WED. 

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

CANYON...

     TROPICAL STORM TODAY INTO MON NIGHT. 



$$ 



.FORECASTER CLARK. OCEAN PREDICTION CENTER.

