AGNT40 KWNM 241456
MIMATN
MARINE WEATHER DISCUSSION
NWS OCEAN PREDICTION CENTER WASHINGTON DC
915 AM EDT TUE 24 APR 2012

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

A LOW PRES CENTER WAS LOCATED OVER SE ONTARIO WITH A EXTENDING
FROM FAR E MAINE SE TO 40N64W THEN S TO 31N64W. A LOW PRES
TROUGH EXTENDED FROM THE SE GULF OF MAINE S TOT 37N68W. WINDS
OVER THE OFFSHORE WATERS WERE S TO SW 15 TO 25 KT E OF THE LOW
PRES TROUGH AND SW TO W 15 TO 25 KT OVER THE REST OF THE AREA.
SEAS AT 12Z WERE 5 TO 11 FT W OF 70W AND 9 TO 18 FT E OF 70W.

THE LOW PRES CENTER WILL MOVE N INTO QUEBEC THIS AFTERNOON AND
TONIGHT WHILE WEAKENING. THE COLD FRONT WILL MOVE WELL E OF THE
AREA. ANOTHER LOW PRES TROUGH WILL MOVE E ACROSS THE CENTRAL AND
N WATERS LATER THIS AFTERNOON AND TONIGHT. HIGH PRES WILL BUILD
INTO THE AREA FROM THE W WED AND WED NIGHT AND EXIT THE WATERS
THU.

FOR THE UPDATE WILL MAKE VERY FEW SHORT TERM CHANGES. THE MODELS
ARE IN GOOD AGREEMENT. THE COLD FRONT IS E OF THE AREA AND THE
LOW PRES TROUGH SHOULD EXIT THE WATERS IN THE AFT. THE MODEL
SHOW WINDS TO 25 KT OVER WRN NT1 AND NW NT2 INTO EARLY AFT AND
AHEAD OF THE NEXT TROUGH MOVING OFF THE COAST LATE TODAY. FOR
THE LONG TERM LOOKING AT PSN OF FRONT ACROSS THE CENTRAL NT2
WATERS ON SAT. THE 06Z GFS IS N OF THE OTHER MODELS WITH THE
FRONT AND DEVELOPS A LOW AT END OF PERIOD. FOR NOW PLAN TO GO
WITH PREVIOUS FCST AND WEAK WINDS N AND SW FLOW S OF THE FRONT.
ALSO WILL KEEP THE FRONT S OF 06Z GFS.

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PREVIOUS DISCUSSION

THE OPC SFC ANALYSIS INDICATED SLOW MOVING COLD FRONT EXTENDING
ACROSS THE GULF OF MAINE AND GEORGES BANK WATERS...AND THEN
EXTENDING S ACROSS THE E PORTION OF THE BALT CANYON TO HAGUE
WATERS. AN ASCAT PASS FROM AROUND 0150Z INDICATED A SMALL AREA
OF 35 KT WINDS OVER THE FAR SE PORTION OF THE BALT CANYON TO
HAGUE WATERS...OTHERWISE WINDS WERE 25 KT OR LESS.

THE 00Z MODELS CONTINUE TO BE IN REASONABLE AGREEMENT THROUGH
MOST OF THE FCST PERIOD. THE MAIN FOCUS FOR THE SHORT TERM
PERIOD IS ON THE FRONT MOVING THROUGH AREA. PLAN ON LETTING THE
GALES FOR THE NT2 WATERS EXPIRE AS SCHEDULED AS THE MODELS ARE
IN EXCELLENT AGREEMENT INDICATING THE GALES E OF THE OFFSHORE
AREA BY 09Z. FOR THE REMAINDER OF TODAY INTO WED...THE MODELS
ALL SIMILAR IN INDICATING SEVERAL SFC TROFS MOVING ACROSS THE
WATERS THROUGH WED WITH SPEEDS REMAINING BELOW GALE. THE NEXT
FRONT IS EXPECTED TO AFFECT THE REGION THU...WITH THE COLD FRONT
MOVING OFFSHORE LATER THU INTO EARLY FRI. THE 00Z GFS HAS
TRENDED A BIT FASTER WITH THE FRONT THAN THE OTHER GLOBAL
MODELS...INCLUDING THE PARALLEL GFS. WITH THIS IN MIND WILL PLAN
ON GOING CLOSE TO THE UKMET/CMC/GFSP/12Z ECMWF WHICH ARE ALL
SLOWER IN MOVING THE FRONT OFFSHORE. WILL ALSO CONTINUE THE
GALES FOR THU OVER A PORTION OF THE NT2 WATERS SINCE ALL THE
MODELS HAVE AT LEAST MARGINAL GALES. THE FRONT WILL THEN
EVENTUALLY STALL OVER THE SRN NT2 WATERS FRI BEFORE WASHING OUT.
WEAK HIGH PRES WILL BUILD OVER THE AREA LATE FRI AND SAT.

SEAS...THE MULTI-GRID WW3 APPEARS TO HAVE A GOOD HANDLE ON SEAS
AS THE SEA STATE ANALYSIS INDICATED THAT OBSERVED SEAS WERE
WITHIN 1-2 FT OF THE MODEL VALUES. PLAN ON GOING CLOSE TO THE
WW3 THROUGH THE PERIOD.

EXTRATROPICAL STORM SURGE GUIDANCE...THE 00Z ETSS WAS SHOWING A
NEG SURGE OF 1 FT FROM LONG ISLAND TO VA BEACH THIS AFT AND
TONIGHT AS THE SW TO W FLOW DEVELOPS. THE MODEL LOOKS
REASONABLE.
.WARNINGS/FORECAST CONFIDENCE...PRELIMINARY. ANY CHANGES WILL BE
COORDINATED THROUGH AWIPS 12 PLANET CHAT OR BY TELEPHONE:

.NT1 NEW ENGLAND WATERS
.GULF OF MAINE...NONE.
.GEORGES BANK...NONE.
.S OF NEW ENGLAND...NONE.

.NT2 MID ATLC WATERS
.HUDSON TO BALT CNYN...NONE.
.BALT CNYN TO HAGUE LINE...GALE THU...LOW TO MDT CONFDC.
.BALT CNYN TO HATTERAS CNYN...GALE THU...LOW TO MDT CONFDC.
.HATTERAS CNYN TO CAPE FEAR...GALE THU...LOW TO MDT CONFDC.
.CAPE FEAR TO 31N...NONE.

.FORECASTER OSZAJCA/KOSIER. OCEAN FORECAST BRANCH.