Marine Interpretation Message
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000
AGNT40 KWNM 211252
MIMATN

MARINE WEATHER DISCUSSION FOR N ATLANTIC OCEAN
NWS OCEAN PREDICTION CENTER WASHINGTON DC
852 AM EDT MON APR 21 2014

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

LOW PRES NR 33N71W CONTS TO SLOWLY DRIFT ENE. PER THE LATEST SFC
OBS MARGINAL ASCD NNELY GALES ARE STIL LKLY PRESENT INVOF THE
GULF STREAM FM CP HAT TO CP FEAR. MAX ASCD SEAS IN THIS VCNTY ARE
IN THE 12-15 FT RANGE WHICH ARE BEING HANDLED SLIGHTLY BETTER BY
THE 06Z WAVEWATCH III VS THE 00Z ECMWF WAM.

OVER THE SHORT TERM...ALL OF THE LATEST MDLS ARE IN RSNBLY GOOD
AGRMT THAT THE SFC LOW WL CONT TO MOVE OFF TO THE ENE
TODAY/TONITE WHILE AT THE SAME TIME THE STRONG HIGH PRES RIDGE
ACRS THE NT1 WTRS WEAKENS WHICH WL ALLOW THE GRADIENT BTWN THE
TWO SYSTEMS TO WEAKEN. AS A RESULT WL ALLOW THE CURRENT GALE WRNGS
TO EXPIRE BEFORE ISSUING THE NEXT UPDATED NT2 FCST. OTHERWISE DO
NOT ANTICIPATE MAKING ANY SIG CHNGS TO THE PREV OFSHR FCSTS THRU
TUE. ON TUE NITE WL USE A COMPROMISE 00Z/06Z GFS AND 00Z ECMWF
SOLUTION FOR A SFC LOW MOVG INTO THE GULF OF MAINE WHILE PULLING A
COLD FRONT OFSHR. SO PER THIS COMPROMISE WL JUST MAKE SM MINOR
TWEAKS TO THE PREVLY FCST CONDS TUE NITE BUT WL NOT REPOPULATE
OUR FCST GRIDS.

IN THE LONG RANGE...SINCE THEY OVERALL ARE IN RSNBLY GOOD AGRMT...WL
CONT TO USE A BLENDED 00Z/06Z GFS AND 00Z ECMWF SOLUTION FOR THE
DVLPG SFC LOW PASSING E ACRS THE NT1 WTRS WED...THEN INTENSIFYG
WED NITE INTO THU WHILE IT DRIFTS OFF TO THE E CAUSING A STRONG
NNWLY GRADIENT IN ITS WAKE ACRS THE NT1 AND NRN/CNTRL NT2 WTRS.
AGAIN WL NOT REPOPULATE OUR FCST GRIDS BUT WL MAKE SM MINOR CHNGS
TO THEM IN DEFERENCE TO THE 06Z GFS. SO OVERALL NO MAJOR CHNGS ARE
PLANNED TO THE PREVLY FCSTD PSBL GALES WITH THIS SYSTEM AND WL
JUST REFINE THE ASCD FCST CONDS.


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

LATEST ASCAT PASS FROM 01Z INDICATES GALE CONDITIONS ARE MAINLY
FOUND IN THE INNER OFFSHORE WATERS ALONG THE CAROLINAS IN THE
VCNTY OF THE GULF STREAM. EXPECT THE GRADIENT TO GRADUALL WEAKEN
OVER NEXT 12-24 HRS AS THE LOW WEAKENS AND PULLS AWAY FROM THE E
CST. THERE ARE SOME SLIGHT DIFFERENCES IN THE TRACK BETWEEN THE
LATEST OF THE LOW AS FCST BY THE NAM AND GFS MODELS. THE NAM TAKES
TEH THE LOW AND STRONGER WINDS FURTHER N THAND THE GFS DOES...AL
LEAST INITIALLY. MOST OF THE OTHER GLOBAL MODELS ARE MORE IN LINE
WITHE THE GFS AND IM NOT GIVING THE NAM TO MUCH CREDENCE ATTM. AS
THE LOW LIFTS NE A RIDGE WILL BRIEFLY OCCUPY THE OFFSHORE WATERS
INADV OF THE NEXT STRONG COLD FRONT MOVING OFF THE MID ATLANTIC
CST TUE NIGHT. THE GLOBAL MODELS ALL SEEM TO BE IN PRETTY GOOD
AGREEMENT WITH THIS SYSTEM AS WELL AND GALES ARE EXPECTED ON THE
BACK SIDE IN THE NW FLOW WED AND THU. THE GALES ARE LIKELY ACROSS
THE ENTIRE NT1 WATERS AND THE NE PORTION OF HTE NT2 WATERS. THE SW
PORTION OF THE NT2 WATERS WILL BE DOMINATED BY A RIDGE AXIS NOSING
S OFF THE SE CST. WHEN POPULATING THE GRIDS I USED A BLEND OF HTE
30M AND 10 M GFS WINDS DEPENDING ON THE STABILITY AND WHETHER I
WANTED A LITTLE MORE WIND SPEED...ESPECIALLY IN THE NW FLOW. LATER
IN THE WEEK AS A STRONG COLD FRONT MOVES OFFSHORE AND BRINGS GALES
ON THE BACKSIDE I DECIDED TO USE A BLEND OF HTE 00Z GFS AND ECWMF
MODELS. THE GFS IS SLIGHTLY FURTHER N WITH THE POSITION OF HTE LOW
ONCE IT MOVES OFF THE CST AND DEEPENDS...THAN THE ECMWF...AND FELT
A COMPROMISE WAS A PRUDENT WAY TO GO.

SEAS...THE WAVE WATCH WAS INITIALIZED PRETTY GOOD...MAYBE A FOOT
LOW AS BUOY 41025 RPT 17 FT AT 07Z...BUT OTHERWISE NOT MUCH
DESCREPENCY HERE. WHEN POPULATING THE GRIDES I WILL USE A 50/50
BLEND OF WAVY WATCH AND ECMWF WAVE GUID THROUGHOUT THE FORECAST
TIME PERIOD.

EXTRATROPICAL STORM SURGE GUIDANCE...IN THE NNELY GRADIENT OFF
THE SE COAST THE 00Z ESTOFS FCSTS A SLIGHTLY MR SIG POSTIVE SURGE
THAN THE 00Z ETSS THRU MON WHICH LOOK REASONABLE. OTHERWISE THE
TWO MDLS ARE SMLR.


.WARNINGS...PRELIMINARY. ANY CHANGES WILL BE COORDINATED THROUGH
AWIPS 12 PLANET CHAT OR BY TELEPHONE:

.NT1 NEW ENGLAND WATERS...
.ANZ800...GULF OF MAINE...
     GALE POSSIBLE WED NIGHT INTO THU NIGHT.
.ANZ805...GEORGES BANK EAST OF 68W...
     GALE POSSIBLE WED NIGHT INTO THU.
.ANZ900...GEORGES BANK WEST OF 68W...
     GALE POSSIBLE WED NIGHT INTO THU NIGHT.
.ANZ810...SOUTH OF NEW ENGLAND...
     GALE POSSIBLE WED NIGHT INTO THU.
.ANZ815...SOUTH OF LONG ISLAND...
     GALE POSSIBLE WED NIGHT.

.NT2 MID ATLC WATERS...
.ANZ915...HUDSON CANYON TO THE GREAT SOUTH CHANNEL...
     GALE POSSIBLE WED NIGHT.
.ANZ920...BALTIMORE CANYON TO THE GREAT SOUTH CHANNEL...
     GALE POSSIBLE WED NIGHT.
.ANZ905...THE GREAT SOUTH CHANNEL TO THE HAGUE LINE...
     GALE POSSIBLE WED NIGHT INTO THU NIGHT.
.ANZ910...EAST OF THE GREAT SOUTH CHANNEL AND SOUTH OF 39N...
     GALE POSSIBLE WED NIGHT INTO THU NIGHT.

$$

.FORECASTER VUKITS/SHAW. OCEAN PREDICTION CENTER.



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