Marine Interpretation Message
Issued by NWS

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AGNT40 KWNM 181343
MIMATN

MARINE WEATHER DISCUSSION FOR N ATLANTIC OCEAN
NWS OCEAN PREDICTION CENTER WASHINGTON DC
843 AM EST THU 18 DEC 2014

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

AT 12Z 993 MB SFC LOW WAS CENTERED NEAR PRINCE EDWARD ISLAND.
WILL CONTINUE WITH PREVIOUS GLWS GEORGES BANK AND NERN MOST MID
ATLC ZONES INTO THIS AFTERNOON. LAST NGTS ASCAT OVERPASSES
RETURNED 20 TO 30 KT OFFSHORE N OF BALT CNYN. SHOULD SEE SOME
FURTHER ENHANCEMENT OF WINDS WITHIN NEXT COUPLE HOURS OVER OUTER
WATERS BEHIND SECONDARY COLD FRONT JUST SE OF GEORGES BANK AND
EXTENDING SW ACROSS NT2 WATERS. HAVE LONG HISTORY ON SHIP WHICH
REPORTED 37 KT AT 12Z WELL OFFSHORE SE OF CAPE MAY AND JUST NW
OF GULF STREAM. ITS MEAN WIND SPEED ERROR WAS CLOSE TO +6 KT.

AS HAS BEEN THE CASE FOR SEVERAL DAYS MODELS CONTINUE TO SHOW
LITTLE RUN TO RUN CONSISTENCY OR AGREEMENT WITH DVLPG MID ATLC
COASTAL LOW LATE SAT INTO EARLY NEXT WEEK. MOST MODELS HAD
TRENDED WEAKER AND SLOWER OVER PAST COUPLE DAYS. HOWEVER THE
00Z/06Z GFS ARE NOW STRONGER EVEN INDICATING GALES ASSOCIATED
WITH LOW AND ALONG WITH THE PARALLEL GFS ALSO TRACK LOW FURTHER
NW WITHIN 70 TO 80 NM OF CAPE COD TUE EVENING. HAVE VERY LOW
CONFIDENCE WITH FORECAST AT DAYS 3-5. MODELS ARE IN BETTER
AGREEMENT LATER NEXT WEEK WITH LARGE UPPER LOW DEVELOPING OVER
ERN US AND STRONG COLD FRONT APPROACHING COAST AND MOVING
OFFSHORE WED/WED NIGHT. AM ANTICIPATING THAT WILL LIKELY HAVE TO
MAKE SOME CHANGES TO WIND GRIDS LATE SAT THROUGH EARLY NEXT WEEK
BUT WILL WAIT FOR 12Z GUIDANCE BEFORE MAKING ANY SIGNIFICANT
MODIFICATIONS.

06Z MULTIGRID WAVEWATCH III IS ABOUT 1 TO 2 FT LOW WITH SIG WV
HGTS OVER OFFSHORE WATERS N OF BALT CNYN. BUOY 44066 HAS BEEN
REPORTING 9 TO 10 FT PAST SEVERAL HRS.

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

SUMMARY...STRENGTHENING LOW PRES OVER THE GLF OF MAINE WILL PASS
NE OVER NOVA SCOTIA TODAY AND TONITE. A HIGH PRES RIDGE WILL
MOVE E TOWARD THE AREA FRI INTO FRI NITE...BUILD OVER THE WATERS
SAT INTO SAT NITE...THEN PASS NE OF THE AREA SUN AND SUN NITE.
DVLPG LOW PRES WILL MOVE OFF THE SOUTH CAROLINA COAST LATE
SAT...THEN DRIFT NE ACROSS THE NT2 AREA SAT NITE THRU MON NITE
WHILE PULLING A COLD FNT E INTO THE NT2 WTRS.

MODELS...THE 00Z MED RNG MDLS ARE IN GUD OVERALL AGREEMNT ACROSS
THE OFSHR WTRS THRU SAT...SO THE 00Z GFS 30M WILL BE USED TO
POPULATE THE WIND GRIDS FOR THIS TIMEFRAME. HOWEVER...THE MED
RNG MDLS HAVE BEEN SHOWING POOR RUN TO RUN CONSISTENCY OVER THE
PAST FEW RUNS REGARDING THE DVLPG COASTAL LOWS...AND THEY ARE
NOT IN GUD AGREEMNT CONCERNING TIMING/STRENGTH/TRAJECTORY OF THE
DVLPG COASTAL LOWS DURING THE SUN THRU MON NITE PRD. WILL BE
USING THE ECMWF FOR SAT NITE THRU MON NITE...SINCE THE 00Z ECMWF
HAS GUD SUPPORT FROM THE LATEST WPC MED RNG FCSTR GUIDANCE.

SEAS...THE 00Z MULTIGRID WW3 MDL GUIDANCE LOOKS REASONABLE OVER
THE OFSHR WTRS FOR TODAY THRU SAT. GIVEN THAT THE 00Z ECMWF IS
THE PREFERRED MDL FOR SUN THRU MON NITE...THE 00Z ECMWF WAM WILL
BE USED TO POPULATE THE SEA HT GRIDS FOR THIS PRD.

.EXTRATROPICAL STORM SURGE GUIDANCE...WITH OFSHR WINDS FOR THE
NEXT COUPLE OF DAYS...BOTH ESTOFS AND ETSS SHOW A NEGATIVE
SURGE...WITH ESTOFS IN 1.0 TO 1.5 FT RANGE FROM VA CAPES TO
MARTHAS VYD TONITE THRU FRI. ETSS IS LESS NEGATIVE WITH SURGE
VALUES UP TO 1.0 FT. A BLEND OF THESE TWO MODELS IS PREFERRED.

.WARNINGS...PRELIMINARY.

.NT1 NEW ENGLAND WATERS...
.ANZ805...GEORGES BANK WEST OF 68W...
     GALE TODAY.
.ANZ900...GEORGES BANK EAST OF 68W...
     GALE TODAY.

.NT2 MID ATLC WATERS...
.ANZ905...THE GREAT SOUTH CHANNEL TO THE HAGUE LINE...
     GALE TODAY.
.ANZ910...EAST OF THE GREAT SOUTH CHANNEL AND SOUTH OF 39N...
     GALE TODAY.

$$

.FORECASTER CLARK/SCOVIL. OCEAN PREDICTION CENTER.


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