511 
AGNT40 KWNM 231311
MIMATN

MARINE WEATHER DISCUSSION 
NWS OCEAN PREDICTION CENTER WASHINGTON DC
730 AM EST MON 23 NOV 2009 

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

AT 12Z THE LATEST SFC OBSERVATION SHOWED E TO NE WINDS 15 TO 25 
KT FROM BALTIMORE CANYON N TO THE GULF OF MAINE AND OVER THE NW 
CORNER OF BALTIMORE CANYON TO HATTERAS CANYON. THE STRONGER 
WINDS ALSO EXTENDING SW FROM CAPE HATTERAS TO CAPE FEAR OVER THE 
COASTAL AND FAR W OFFSHORE WATERS. ELSEWHERE WINDS WERE SE TO S 
10 TO 15 KT. SEAS WERE 9 TO 11 FT BETWEEN CAPE COD AND BALTIMORE 
CANYON...3 TO 6 FT OVER THE GULF OF MAINE AND 6 TO 8 FT S OF 
BALTIMORE CANYON. 

A DEVELOPING LOW PRES CENTER AT 12Z LOCATED TO THE SE OF CAPE 
LOOKOUT WILL MOVE NE TO CAPE HATTERAS BY EVENING THEN CONTINUE 
NE TO SW GEORGES BANK BY TUE MORNING. THE LOW WILL EXIT GEORGES 
BANK EARLY WED. DRAGGING A COLD FRONT E ACROSS THE NT2 WATERS. 

THE MODELS HAVE THE GENERAL PATTERN WITH THE NAM NOT ON BOARD 
WITH THE LOW MOVING INTO GEORGES BANK TUE. NO PLAN TO USE THE 
NAM TODAY. THE EC...UKMET AND GEM ARE SLOWER THEN THE 06Z GFS. 
IN ADDITION THE GFS HAS A SOMEWHAT ELONGATED AREA OF LOW PRES 
WITH THE OTHER MODELS FAVORING ONE CENTER. PLAN TO KEEP THE GALE 
UP FOR E TO NE FLOW ARND THE LOW BUT THINK IT WILL BE MARGINAL. 
NO CHARGES FOR THE UPDATE.  

------------------------------------------------------------
PREVIOUS DISCUSSION

LARGE HIGH PRES CONTS TO BUILD SE ACROSS THE NRN WATERS... 
SUPPORTING MOD NE FLOW OF 20 TO 25 KT OVR MOST OF THE OFFSHORE 
WATERS TNGT...XCPT EXCEPT FAR NW WATERS 15 TO 20 KT. MODELS CONT 
TO FCST LOW PRES TO DVLP OFFSHORE AND MOVE TO E OF THE VA CAPES 
BY LATE AFTN...THEN CONT TO DEEPEN AND MOVE LOW NE TNGT THRU 
TUE. GFS HAS BEEN FAIRLY CONSISTENT WITH THIS FCST...ONLY LATEST 
RUNS ARE DEEPER. LL VORT FIELDS INDCT GFS IS HAVING MINOR 
CONVECTIVE FEEDBACK PRBLMS. THE GFSP IS SMLR TO THE OP 
GFS...THOUGH JUST A BIT MORE TEPID ON DEEPENING THE LOW. THE 
ECMWF/UKMET/CDN ARE SMLR...WITH ALL THE MODELS ARRIVING AT A 
FCST OF THE SFC LOW OVER ERN GEORGES BANK AT 00Z WED. 
ODDLY...THE GFS ENSMBL MEAN IS SE OF ALL GLOBAL MODELS. THE GFS 
IS 3 TO 4 MBS DEEPER THAN THE OTHER MODELS. THE NAM...NEVER 
CATCHES ON AND TAKES A VERY WEAK LOW AND MOVES IT 
EASTWARD...THEN NORTHWARD AND IS DISCARDED. 

WILL CONT WITH E GALES DVLPNG AT 00Z TNGT S OF NEW ENGLAND 
WATERS...THEN ACROSS THE RMNDR OF THE NRTRN WATERS TNGT. XPCT 
GALES TO END TUE AND TUE NGT. WILL STAY WITH MINIMAL GALES... 
INSTEAD THE HIGHER 40 RO 45 KT FCST BY THE OVERDONE GFS. 

NEXT FCST PRBLM IS LATE THU AND FRI. MODELS CONT TO HAVE PRBLMS 
IN TIMING OF DVLPNG CUT OFF UPR LOW OVR THE OHIO VLLY LATE 
THU... THEN BRINGING LARGE UPR LOW EASTWARD. THE GFS AND ECMWF 
ARE THE MOST ALIKE WHILE THE CDN AND ESP THE UKMET CONTS TO BE 
TOO PROGRESSIVE. ON THE SFC...A SIG CYCLONE IS LIKELY TO AFFECT 
THE OFFSHORE WATERS FRI. DETAILS ARE DFFCLT AT THIS POINT WITH 
CONFIDENCE LACKING. WL FCST A MIX OF THE NEW GFS AND ECMWF... 
LEANING MORE TWDS THE LATTER. THE GFS ENSMBL MEMBERS ARE 
SCATTERED ABOUT AND OFFER LITTLE...EXCEPT TO CONFIRM THAT 
CONFIDENCE SHOULD BE LOW. BEST BET FOR GALES ATTM IS FOR LATE 
FRI...EARLY SAT IN UNSTABLE CAA IN WAKE OF SFC LOW OFF THE MID 
ATLC COAST. BUT OWING TO LOW CONFIDENCE...WL KP WINDS CHECKED AT 
30 KT MAXIMUM. 

SEAS...CURRENTLY...OBSRVTNS COMPARED WITH THE W ATLC WAVE WATCH 
MODEL ARE RUNNING 2 TO 3 FT ABOVE THE MODELS OFF THE NC AND SC 
COAST. SEAS HERE SHLD GRADU SUBSIDE AS WINDS VEER TO S'RLY AND 
DMNSH TODAY. AND OVER BALT CNYN...SEAS ARE 1 TO 2 FT ABV GDNC... 
AND DO NOT SEE MUCH OF A REASON TO CHANGE. ELSEWHERE...WL FLLW 
WAVE WATCH GUIDANCE...XCPT LOW SEAS 1 OR 2 FT IN ASSN WITH 
SLGTLY OVERFCST LOW. ALSO...LATE FRI...WL TRIM BACK SEAS 20 TO 
25 PCT OVR THE OUTER OFFSHORE WATERS. 

EXTRATROPICAL STORM SURGE...FCST LVLS REACH JUST OVER 1 FT ALONG 
THE NJ COAST 12Z TUE. SINCE GFS WINDS ARE OVERDONE...THESE HGTS 
MAY BE A LTTL TOO HIGH. 

.WARNINGS/FORECAST CONFIDENCE...WARNINGS ARE PRELIMINARY AND ARE 
SUBJECT TO CHANGE. ANY CHANGES WILL BE COORDINATED THROUGH AWIPS 
12 PLANET CHAT OR BY TELEPHONE. 

.NT1 NEW ENGLAND WATERS... 
.GULF OF MAINE...GALE TNGT INTO TUE...LOW CONFDC. GALE FRI...LOW 
CONFDC. 
.GEORGES BANK...GALE THIS AFT INTO TUE...LOW TO MDT CONFDC. 
.S OF NEW ENGLAND...GALE THIS AFT INTO TUE...LOW TO MDT CONFDC. 

.NT2 MID ATLC WATERS... 
.HUDSON TO BALT CNYN...NONE. 
.BALT CNYN TO HAGUE LINE...GALE THIS AFT INTO TNGT E PART...LOW 
TO MDT CONFDC. GALE FRI E PART...LOW CONFDC. 
.BALT CNYN TO HATTERAS CNYN...NONE. 
.HATTERAS CNYN TO CAPE FEAR...NONE. 
.CAPE FEAR TO 31N...NONE. 

.FORECASTER OSZAJCA/PROSISE. OCEAN FORECAST BRANCH.