973 
AGNT40 KWNM 281911
MIMATN

MARINE WEATHER DISCUSSION 
NWS OCEAN PREDICTION CENTER WASHINGTON DC
300 PM EDT SUN 28 OCT 2012 

.FORECAST DISCUSSION: MAJOR FEATURES/WINDS/SEAS/SIGNIFICANT 
.WEATHER FOR NORTH ATLANTIC OCEAN W OF 50W FROM 30N TO 50N. 

NOTE: ISSUANCE OF NEW ENGL AND MID ATLC OFFSHORE WATER FORECASTS 
WILL BE DELAYED UNTIL 21Z NHC ADVISORY IS AVAILABLE.

LATEST NHC FORECAST WAS CONSISTENT WITH PREVIOUS ADVISORIES WITH 
TRACK OF HURCN SANDY...AND ALSO MAINTAINS SANDY AS TRPCL CYCLONE 
THRU 36HRS. ADJUSTED HEADLINES OVER NEW ENGL WATERS TO STORM/ 
HURCN FORCE WIND WARNINGS TO BE CONSISTENT WITH COASTAL WFOS AND 
ALSO ACCOUNT FOR POST TRPCL TRANSITION AS INDICATED BY EARLIER 
NHC ADVISORIES. HOWEVER THIS EXTRATROPICAL TRANSITION HAS LITTLE 
BEARING ON THE FACT THAT SANDY WILL REMAIN A DANGEROUS STORM 
WITH HURCN FORCE WINDS...LIFE THREATENING STORM SURGE AND HEAVY 
RAINFALL. 12Z GFS WAS CONSISTENT WITH ITS PREVIOUS RUN AND 
REMAINS FASTER THAN 12Z UKMET/ECMWF AND ALSO OFFICIAL NHC 
FORECAST...MAINLY AT 24 HRS AND BEYOND. OVERALL DO NOT 
ANTICIPATE THAT THERE WILL BE MUCH CHANGE NEEDED FROM PREVIOUSLY 
FORECAST WARNINGS. AT 15Z SHIP REPORTING 60 KT AND 47 FT WITHIN 
GLF STREAM WAS LIKELY A GOOD OB. WILL BE ADJUSTING 12Z MULTIGRID 
WAVEWATCH III SIG WV HGTS ASSOC WITH SANDY ABOUT 6 TO 8 FT OR 
HIGHER.          
WILL BE UPDATING STORM SURGE DETAILS BELOW BASED ON NHC 
CONFERENCE CALL AND ADVISORY IN AN UPDATED MARINE DISCUSSION TO 
FOLLOW SHORTLY. 

EXTRATROPICAL STORM SURGE GUIDANCE...WILL BE UPDATED VIA NEW 
PUBLIC NHC ADVISORY. STORM SURGE...THE COMBINATION OF A 
DANGEROUS STORM SURGE AND THE TIDE WILL CAUSE NORMALLY DRY AREAS 
NEAR THE COAST TO BE FLOODED BY RISING WATERS. THE WATER COULD 
REACH THE FOLLOWING DEPTHS ABOVE GROUND IF THE PEAK SURGE OCCURS 
AT THE TIME OF HIGH TIDE... 

NC NORTH OF SURF CITY INCLUDING PAMLICO/ALBERMARLE SNDS...4 TO 6 
FT 
SE VA AND DELMARVA INCLUDING LOWER CHESAPEAKE BAY...2 TO 4 FT. 
UPPER AND MIDDLE CHESAPEAKE BAY...1 TO 3 FT.
LONG ISLAND SOUND...RARITAN BAY...AND NEW YORK HARBOR...6 TO 11 
FT.
ELSEWHERE FROM OCEAN CITY MD TO THE CT/RI BORDER...4 TO 8 FT. 
CT/RI BORDER TO THE SOUTH SHORE OF CAPE COD INCLUDING BUZZARDS 
BAY AND NARRAGANSETT...3 TO 6 FT. 

SURGE-RELATED FLOODING DEPENDS ON THE RELATIVE TIMING OF THE 
SURGE AND THE TIDAL CYCLE...AND CAN VARY GREATLY OVER SHORT 
DISTANCES. GIVEN THE LARGE WIND FIELD ASSOCIATED WITH 
SANDY...ELEVATED WATER LEVELS COULD SPAN MULTIPLE TIDE CYCLES 
RESULTING IN REPEATED AND EXTENDED PERIODS OF COASTAL AND 
BAYSIDE FLOODING. IN ADDITION... ELEVATED WATERS COULD OCCUR FAR 
REMOVED FROM THE CENTER OF SANDY. FURTHERMORE...THESE CONDITIONS 
WILL OCCUR REGARDLESS OF WHETHER SANDY IS A TROPICAL OR 
POST-TROPICAL CYCLONE. FOR INFORMATION SPECIFIC TO YOUR 
AREA...PLEASE SEE PRODUCTS ISSUED BY YOUR LOCAL NATIONAL WEATHER 
SERVICE WASHINGTON DC

.WARNINGS/FORECAST CONFIDENCE...PRELIMINARY AND MAY BE AMENDED 
BASED ON LATEST NHC ADVISORY. ANY CHANGES WILL BE COORDINATED 
THROUGH AWIPS 12 PLANET CHAT OR BY TELEPHONE: 

.NT1 NEW ENGLAND WATERS 
.GULF OF MAINE...STORM...TNGT INTO TUE. 
.GEORGES BANK...STORM...TNGT INTO TUE. 
.S OF NEW ENGLAND...HURCN FORCE WIND MON INTO MON NGT. 

.NT2 MID ATLC WATERS 
.HUDSON CNYN TO BALT CNYN...HURN...MON INTO MON NGT. 
.BALT CNYN TO HAGUE LINE...HURCN...TNGT INTO MON NGT. 
.BALT CNYN TO HATTERAS CNYN...HURCN...TNGT INTO MON. 
.HATTERAS CNYN TO CAPE FEAR...HURCN...TNGT. 
.CAPE FEAR TO 31N...HURCN...TNGT. 

.FORECASTER CLARK. OCEAN FORECAST BRANCH.