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000
AGNT40 KWNM 151246
MIMATN

MARINE WEATHER DISCUSSION FOR N ATLANTIC OCEAN
NWS OCEAN PREDICTION CENTER WASHINGTON DC
846 AM EDT WED 15 MAY 2013

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

00Z/06Z MDLS DID NOT OFFER SIGNIFICANT DIFFERENCES FROM
YESTERDAYS RUNS CONCERNING FROPA AND ASSOC STRONG TO GALE
PREFRNTL WINDS TNGT INTO THU. WILL CONTINUE WITH MARGINAL GALES
BALT CNYN TO HAGUE LINE WATERS TNGT INTO EARLY THU. ALSO
ECMWF/UKMET HAVE CONSISTENTLY LIMITED SFC WINDS BALT TO HATTERAS
CNYNS TO 25 KT AND GIVEN SLIGHT LOW BIAS IN THESE WINDS...WILL
HOLD WINDS TO 30 KT OVER THIS ZONE...CONSISTENT WITH GFS 10M
WINDS. LITTLE POTENTIAL FOR ANY MIXING OVER COLDER NEW ENGL AND
SHELF WATERS BASED ON NAM LOW LVL LAPSE RATES...WHICH BETTER
CAPTURE GLF STREAM. IN THE MED RANGE SAT/SUN 00Z GFS TRENDED
TWRD PREFERRED ECMWF/UKMET BLEND. HOWEVER 06Z GFS IS AGAIN
STRONGER WITH UPPER VORTS/SFC LOWS PASSING E OFF MID ATLC COAST
AND ALONG STNRY FRONT SUN. WILL MAINTAIN FORECAST CONTINUITY
WITH THIS MORNINGS UPDATES.

06Z MULTIGRID WAVEWATCH III SIG WV HGTS LOOK REASONABLE WHEN
COMPARED TO W ATLC SHIP/BUOY OBS OVER PAST FEW HRS. FOR TNGT
INTO THU PREFER THE SLIGHTLY HIER 00Z ECMWF WV MDL THO.

-----------------------------------------------------------------
...PREVIOUS DISCUSSION...

A LOW PRES CENTER WAS LOCATED OVER ERN NOVA SCOTIA WITH A COLD
FRONT EXTENDING S ALONG 57W TO ANOTHER LOW 260 NM NE OF BERMUDA.
A HIGH PRES CENTER WAS LOCATED 185 NM SE OF CAPE FEAR WITH A
RIDGE EXTENDING NE ACROSS THE OFFSHORE WATERS AND INLAND OVER
ERN NEW ENGLAND. A SECOND RIDGE EXTENDS W TO THE SE U.S. AND
INTO THE GULF OF MX. WINDS OVER THE WATERS WERE W TO SW 10 TO 15
KT ACROSS NT1 AND NT2 N OF BALTIMORE CANYON...SW 10 TO 15 KT W
OF 1000 FM S OF HATTERAS CANYON AND VARIABLE 5 TO 10 KT
ELSEWHERE. SEAS 2 TO 8 FT WITH THE HIGHEST IN ERN PORTIONS.

SHORT TERM...THE HIGH PRES RIDGE ACROSS THE AREA THIS MORNING
WILL WEAKEN THIS AFT AND TONIGHT. A WARM FRONT WILL MOVE NE
ALONG THE COAST TONIGHT AND THU. A COLD FRONT WILL MOVE OFFSHORE
TONIGHT FOLLOWED BY A SECOND COLD FRONT THU NIGHT. THE SECOND
FRONT WILL STALL ACROSS THE CENTRAL WATERS NEAR CAPE HATTERAS
FRI. HIGH PRES WILL BUILD OVER THE AREA N OF THE STALLED FRONT
THU NIGHT AND FRI.

THE MODELS ARE IN AGREEMENT OVER THE SHORT TERM WITH WINDS INC
TO GALE FORCE AHEAD OF THE FIRST COLD FRONT. THE GALE AREA WILL
BE IN THE ERN WATERS S OF THE GULF STREAM AND E OF 1000 FM. THE
NAM IS TOO STRONG WITH THE WINDS AND THE GEM HAS SEVERAL AREAS
OF 35 KT. THE GFS AND ECWMF ARE CLOSE WITH E PORTION OF
BALTIMORE CANYON TO HAGUE LINE. ELSEWHERE N OF THE GULF STREAM
THE WATER IS STILL TOO COLD SO WINDS MAY NOT MIXED DOWN. FOR
HATTERAS CANYON TO BALTIMORE CANYON WILL HOLD AT 30 KT BUT A
BRIEF GALE MAY EXTEND INTO NE PORTION.

LONG TERM...THE STALLED FRONT ACROSS THE CENTRAL WATERS SAT
REMAINS INTO MON. HIGH PRES OVER THE N WATERS WILL MOVE SLOWLY E
THROUGH MON. AS THE HIGH MOVES E THE FRONT BECOMES STRETCHED
FROM NW TO SE ACROSS NT2. FOR LONG TERM WILL CONTINUE TO USE THE
GFS THROUGH SUN. THE GFS HAS BACKED OFF ON THE STRONG WINDS N OF
THE FRONT AND CHANGED TO A GENTLE SE FLOW SUN. THE GFS LOOKS
REASONABLE FROM RUN TO RUN AND IS WEAKER THAN THE 12Z AND 18Z
RUNS WITH WINDS N OF THE FRONT.

SEAS...THE MULTIGRID MODEL LOOKS FINE. PLAN TO FOLLOW THOUGH
SUN. HAVE INC SEAS 1 TO 2 FT IN WARNING AREA TO BLEND WITH THE
ECWMF WAM. THE ECWMF WAM IS SLIGHTLY HIGHER WITH THE SEAS IN
WARNING AREA TONIGHT INTO THU.

EXTRATROPICAL STORM SURGE MODEL...N/A.

.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.
.SOUTH OF NEW ENGLAND...NONE.

.NT2 MID ATLC WATERS...
.HUDSON CANYON TO BALTIMORE CANYON...NONE.
.BALTIMORE CANYON TO HAGUE LINE...GALE TNGT INTO THU...LOW TO
MOD CONFDC.
.BALTIMORE CANYON TO HATTERAS CANYON...NONE.
.HATTERAS CANYON TO CAPE FEAR...NONE.
.CAPE FEAR TO 31N...NONE.
$$

.FORECASTER CLARK/OSZAJCA. OCEAN PREDICTION CENTER.