Marine Interpretation Message
Issued by NWS

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000
AGNT40 KWNM 220651
MIMATN

MARINE WEATHER DISCUSSION FOR N ATLANTIC OCEAN
NWS OCEAN PREDICTION CENTER WASHINGTON DC
251 AM EDT MON SEP 22 2014

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

OVER THE SHORT TERM...AN EARLIER 0214Z ASCAT-B PASS CONFIRMED
THAT SSWLY GALE FORCE WINDS WERE PRESENT IN THE SSWLY GRADIENT
ACRS THE SE MOST NT1 AND NE NT2 WTRS IN ADVANCE OF THE COLD FRONT
TRAILING FM THE LOW PRES CENTER NOW PASSING NE ACRS THE SE GULF OF
MAINE. BY THE START OF THE TODAY FCST PERIOD ALL OF THE NEW 00Z
MDLS FCST THE LOW TO RACE OFF TO THE NE WITH ITS COLD FRONT AND
GALE FORCE ASCD WINDS E OF THE OFSHR WTRS. THEN THE MDLS ALL FCST
ANOTHER COLD FRONT TO SLIDE OFSHR TODAY ACRS THE NT1 AND NRN/CNTRL
NT2 WTRS...CONT SE INTO SRN NT2 WTRS TONITE...THEN STALL AND
WEAKEN ACRS THE SRN NT2 WTRS TUE/TUE NITE WHILE STRONG HIGH PRES
BUILDS IN FROM THE NW CAUSING A MOD STRONG (PRIMARILY IN THE 20-30
KT RANGE) ENELY GRADIENT TO DVLP ACSR THE NT2 WTRS. BY TUE NITE
THE 00Z NAM/GEM/UKMET INDICATE MARGINAL GALES CULD DVLP IN THE
COUNTERFLOW INVOF THE GULF STREAM ACRS THE S CNTRL NT2 WTRS. FOR
NOW THO WITH THE 00Z GFS/ECMWF FCSTG SMWHT WEAKER GRADIENTS WL
HOLD OFF ON ANY ASCD WRNGS. THEREFORE PLAN ON POPULATING OUR SHORT
TERM GRIDS THRU TUE NITE WITH THE 00Z GFS 30M BL WINDS WITH SM
ADDITIONAL EDITS THEN MADE IN DEFERENCE TO THE 00Z UKMET/ECMWF. SO
ANTICIPATE MAKING GNRLY MINOR SHORT TERM CHNGS TO THE PREV OFSHR
FCSTS.

IN THE LONG RANGE...THE DISPARITY BTWN THE 00Z MDLS INCREASES IN
REGARDS TO THEIR FCST PSN OF A SFC TROF (OR STNRY FRONT) FORMING
NR THE SE COAST AND WHETHER ANY FRONTAL WAVES WL DVLP ALONG IT.
THE 00Z GFS NOW DIFFERS SIGLY VS ITS PREV RESPECTIVE RUNS IN FCSTG
A MR PRONOUNCED SFC TROF EXPANDING NWD WED/WED NITE... SPINS UP AN
ASCD SFC LOW OFF THE MID ATLC COAST EARLY THU WITH GALE FORCE ASCD
BL WINDS...THEN TRACKS THE LOW ENE ACRS THE NRN NT2 WTRS LATER THU
INTO EARLY FRI. WITH LITTLE SUPPORT FROM THE 00Z GEFS AND THE
OTHER 00Z GLOBAL MDLS...WL DISREGARD THIS 00Z GFS SOLUTION. WL
ALSO DISREGARD THE USUALLY AGGRESSIVE 00Z GEM SOLUTION ALSO.
THEREFORE WITH NO MR THAN LOW/MOD FCST CONFIDENCE...WL FAVOR A
BLENDED 00Z UKMET/ECMWF SOLUTION FOR THE LONG RANGE WHICH ARE MR
SUPPRESSED WITH THEIR SFC TROF/FRONT ACRS THE NT2 WTRS AND MR IN
LINE WITH THE LATEST WPC MEDIUM RANGE GUIDANCE. AS THE 00Z
UKMET/ECMWF BOTH FCST THE SFC RIDGE TO THE N TO GRADLY WEAKEN THEY
FCST THE MOD STRONG ENELY GRADIENT ACRS THE NT2 WTRS WED/THU TO
WEAKEN BY LATE FRI/FRI NITE. THEREFORE PLAN ON POPULATING OUR FCST
WIND GRIDS WITH A 50/50 BLEND OF THE 00Z UKMET/ECMWF ON WED THRU
FRI NITE WHICH WL RESULT IN NO MAJOR LONG RANGE CHNGS IN THE NEXT
OFSHR FCST PACKAGE.

.SEAS...THE 00Z WAVEWATCH HAS INITIALIZED THE SEAS THRUT THE NT1
AND NRN/CNTRL NT2 WTRS 1-3 FT ON AVERAGE TOO HIGH. THEREFORE SINCE
ITS ASCD GLOBAL MDL WL BE FAVORED IN THE LONG RANGE ALSO...PLAN
ON POPULATING OUR FCST WAVE GRIDS WITH THE 00Z ECMWF WAM MDL THRUT
THE FCST PERIOD.

.EXTRATROPICAL STORM SURGE GUIDANCE...BY LATE WED INTO THU THE
00Z ESTOFS FCSTS A MR SIG POSITIVE SURGE (UP TO 1 TO 2 FT) DVLPG
ALONG THE MID ATLC COAST THAN THE 00Z ETSS MDL. BUT WITH THE 00Z
GFS NOT BEING FAVORED AT THAT TIME BLV BOTH MDLS ARE LKLY
OVERFCSTG THIS SURGE.

.WARNINGS...PRELIMINARY.

.NT1 NEW ENGLAND WATERS...
     NONE.

.NT2 MID ATLC WATERS...
     NONE.

$$

.FORECASTER VUKITS. OCEAN PREDICTION CENTER.



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