Marine Interpretation Message
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AGNT40 KWNM 270101
MIMATN

MARINE WEATHER DISCUSSION FOR N ATLANTIC OCEAN
NWS OCEAN PREDICTION CENTER WASHINGTON DC
801 PM EST THU FEB 26 2015

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

THE LTST NCEP SFC ANALYS INDC STG LOW PRES E OF THE OFSHR WTRS
ATTM...AND RSCAT WND RTRVLS FM 22Z INDC STORM FRC S OF THE LOW S
CTR...WITH A FEW RMNG GALES OVR THE OFSHR WTRS IN THE STG CAA. THE
SYS IS MOVG QUICKLY TO THE E...AND THE CRNT SFC RPRTS INDC THE
STGST WNDS HAVE MOVD E OF THE OFSHR WTRS...WITH ONLY ABT 25 KT OVR
THE NE OFSHR WTRS RMNG. THE 18/12Z GFS INDC THE LOW WL CONT TO
MOVE OFF THE E VRY QUICKLY TNGT...THO THE TAIL END OF THE FRNTL
BNDRY IS XPCTD TO DRIFT E JUST E OF THE SRN NT2 WTRS. THE GFS CONT
TO INDC A WK LOW WL DVLP JUST NW OF THE FRNT...THEN MOV OFF THE E
BEHIND THE BNDRY. THE GFS IS THE OUTLIER SOLN WITH THIS WK
FEATURE...THO NOT SURE WHY THE MDL KEEPS IT WITH NOT MUCH MID-LVL
SUPPORT. THE PREV FCST PLAYED DN THIS FEATURE...WHICH IS
RSNBL...SO PLANNING ON STAYING ALNG THOSE LINES FOR THE UPDATE
PKG.

OTRW...THE MDLS AGREE SOMEWHAT WELL ON THE SYNOP PTTN THRUT THE
RMNDR OF THE FCST PD...THO MINOR DIFFS APPEAR WITH THE NEXT SYS
MON. THE 12Z ECWMF IS A NRLY OUTLIER WITH THE LOW CTR OF THIS NEXT
SYS...AND TAKES IT TO THE N OF THE NT1 WTRS. THE GFS HAS BEEN TKG
IT THRU THE GULFME ON SUBSEQUENT RUNS...THO IS THE SRN END OF THE
MDL CONSENSUS...ALBEIT MUCH CLOSER TO IT THAN THE ECWMF. DEPITE
THE DIFFS ON THE TRACK...THE GFS AND ECWMF AGREE SOMEWHAT ON THE
PRES GRAD...AND ALL AGREE WITH AT LEAST GALE FORCE OVR THE N PTTN
OF THE OFSHR WTRS MON INTO MON NGT. THE PREV FCST USED THE 12Z GFS
WINDS FOR THIS BNDRY...WHICH SEEMS RSNBL GIVEN THE SLOW DVLPMT OF
THE ECWMF AND THE STG SHRTWV RESPONSIBLE FOR THIS SYS AS SHOWN BY
ALL SOLNS. ATTM PLANNING ON STAYING WITH THE CRNT WRNGS AND TMGS
IN PREV FCST.

ANOTHER LOW IS SHOWN APRCHG THE AREA FM THE W LATE TUE...AND THE
MDLS HAVE DIFFS ON THE TMG. THE GFS HAS BEEN A FAST OUTLIER WITH
THIS SOLN...AND INDC GALES IN THE SRLY FLOW OVR CLDR WTRS N AND W
OF THE GLF STRM. CONFDC IS CRNTLY VRY LOW WITH THE GALES...AS THE
GFS SEEMS TOO FAST TO INCRS THE WNDS...AND TOO STG IN THE SRLY
FLOW. THE PREV FCST TONED DN THE INTNSTY OF THE WINDS...AND SLOWED
DN THE FORWARD MOTION OF THE SYS FROM THE WHAT THE GFS INDCD. THIS
AGAIN SEEMS TO BE A GUD STRATEGY GIVEN THE CONSENSUS OF THE 12Z
UKMET/ECMWF/GEM SOLNS BEING SLOWER...SO PLANNING ON NOT MAKG ANY
SIG CHANGES.

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

OVER THE SHORT TERM...THE NEW 12Z MDLS REMAIN IN EXCELLENT AGRMT
THAT THE STRONG SFC LOW NOW ENE OF CP HATTERAS WL RACE FAR ENUF
TO THE NE THAT BY THE START OF THE TONITE FCST PERIOD THAT ANY
RMNG ASCD GALES WL BCM LIMITED TO THE FAR NE NT2 WTRS...THEN BCM
SUBGALE SHORTLY THEREAFTER TONITE. OTHERWISE VS ITS PREV
RESPECTIVE RUNS...THE 12Z GFS CONTS THE TREND OF BACKING OFF ON
ITS FCST STRENGTH OF A SCNDRY SFC LOW FORMING NR THE OUTER CNTRL
NT2 WTRS LATE TONITE...THEN DRIFTING E OF THE NT2 WTRS FRI/FRI
NITE. BASED ON ITS LACK OF UPR LEVEL SUPPORT AND ENSEMBLE SUPPORT
FROM THE 12Z GEFS...AND THE FACT THAT NO OTHER MDL FCSTS AS STRONG
A FEATURE...SUSPECT THAT THE 12Z GFS IS STIL TOO STRONG WITH THIS
LOW AND ITS ASCD WINDS. OTHERWISE THE 12Z MDLS ARE IN RSNBLY GOOD
AGRMT IN FCSTG STRONG HIGH PRES TO BCM THE DOMINANT SHORT TERM
FEATURE AS IT BLDS TWDS THE MID ATLC COAST FRI INTO SAT NITE WHICH
WL SUPPORT A MOD STRONG (UP TO 25 OR 30 KT) NELY GRADIENT TO DVLP
ACRS THE SRN NT2 WTRS. THEREFORE PLAN ON POPULATING OUR SHORT TERM
FCST WIND GRIDS THRU SAT NITE WITH THE 12Z GFS 30M BL WINDS
(MAINLY TO GET SMWHT HIGHER WINDS IN THE NELY GRADIENT ACRS THE
SRN NT2 WTRS) WITH SM MINOR SUBSEQUENT EDITS TO TWEAK DOWN THE
WINDS INVOF THE SFC LOW LATE TONITE INTO FRI NITE. SO AS A RESULT
EXPECT TO MAKE ONLY MINOR SHORT TERM CHNGS TO THE PREV OFSHR
FCSTS.

IN THE LONG RANGE...THE 12Z MDLS ALL FCST THE HIGH PRES CENTER
TO BLD OFSHR SUN AND THEN PASS SE OF THE NT2 WTRS SUN NITE WITH
DMNSHG ASCD CONDS. THEN THE 12Z MDLS GNRLY AGREE THAT A STRONG
COLD FRONT WL PUSH SE ACRS THE WTRS MON INTO MON NITE WHL AN
ATTENDANT SFC LOW INTENSIFIES E THEN NE OF THE NT1 WTRS. WHL THE
12Z GLOBAL MDLS DIFFER IN RGRDS TO THEIR EXACT FCST TRACKS OF THE
ATTENDANT SFC LOW THEY ARE IN VERY GOOD AGRMT IN RGRDS TO THEIR
FCST TIMING AND ASCD FCST GRADIENTS FOR THE FROPA. THEREFORE FOR
THIS FROPA WL POPULATE WITH THE 12Z GFS 10M BL WINDS INADVOF THE
FRONT SUN/SUN NITE AND THEN WL TRANSITION TO THE STRONGER 12Z GFS
30M BL WINDS MON/MON NITE TO BETTER ACCOUNT FOR THE MOD STRONG
COLD AIR ADVECTION BHND THE FRONT. THEN AFTER THE 12Z MDLS FCST
HIGH PRES TO BLD OFSHR WITH DMNSHG CONDS TUE...TO VARYING DEGREES
THEY FCST STRENGTHENING SLY RETURN FLOW TO DVLP TUE NITE AS THE
FRONT RETURNS N AS A WARM FRONT. THE 12Z GFS/GEM FCST GALE FORCE
BL WINDS TO DVLP IN THIS SLY GRADIENT WHL THE 12Z UKMET/ECMWF FCST
SMWHT WEAKER GRADIENTS WITH THE 12Z ECMWF BEING SMWHT SLOWER IN
STRENGTHENING THE GRADIENT. SO FOR NOW AS A COMPROMISE WL
TRANSITION TO POPULATING WITH THE MR CONSERVATIVE 12Z GFS 10M
WINDS FOR THIS SLY GRADIENT TUE/TUE NITE...TIME SHIFTED 3HRS
SLOWER IN DEFERENCE TO THE SLOWER 12Z ECMWF AND AS A RESULT WL
HOLD OFF ON FCSTG ANY ASCD PSBL GALES FOR NOW.

.SEAS...OVERALL BOTH THE 12Z WAVEWATCH III AND 12Z ECMWF WAM HV
INITIALIZED WELL. WITH THE DIFFS BTWN THE TWO MDLS RMNG MINIMAL
WL POPULATE WITH A 50/50 BLEND OF THE TWO MDLS TONITE THRU MON
NITE...THEN WL TRANSITION TO ALL 12Z WAVEWATCH III FOR TUE/TUE
NITE TIME SHIFTED 3HRS SLOWER.

.EXTRATROPICAL STORM SURGE GUIDANCE...AS THE ENELY GRADIENT
STRENGTHENS ACRS THE SRN NT2 WTRS FRI NITE INTO SUN THE 12Z
ESTOFS RMNS CONSISTENT IN FCSTG A SMWHT HIGHER SURGE TO DVLP ALONG
THE S CAROLINA AND GEORGIA COASTS THAN FCST BY THE 12Z ETSS WHICH
LOOKS RSNBL.


.WARNINGS...PRELIMINARY.

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

.NT2 MID ATLC WATERS...
.ANZ820...HUDSON CANYON TO BALTIMORE CANYON...
     GALE POSSIBLE MON.
.ANZ915...HUDSON CANYON TO THE GREAT SOUTH CHANNEL...
     GALE POSSIBLE MON.
.ANZ920...BALTIMORE CANYON TO THE GREAT SOUTH CHANNEL...
     GALE POSSIBLE MON.
.ANZ905...THE GREAT SOUTH CHANNEL TO THE HAGUE LINE...
     GALE POSSIBLE MON INTO MON NIGHT.
.ANZ910...EAST OF THE GREAT SOUTH CHANNEL AND SOUTH OF 39N...
     GALE POSSIBLE MON INTO MON NIGHT.
.ANZ825...INNER WATERS FROM BALTIMORE CANYON TO CAPE CHARLES LIGHT...
     GALE POSSIBLE MON.
.ANZ925...OUTER WATERS FROM BALTIMORE CANYON TO HATTERAS CANYON...
     GALE POSSIBLE MON.

$$

.FORECASTER KELLS/VUKITS. OCEAN PREDICTION CENTER.


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