Marine Interpretation Message
Issued by NWS

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
AGNT40 KWNM 271304
MIMATN

MARINE WEATHER DISCUSSION FOR N ATLANTIC OCEAN
NWS OCEAN PREDICTION CENTER WASHINGTON DC
904 AM EDT MON APR 27 2015

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

THE 06Z GFS DIDNT ADD MUCH TO CONSOLIDATE THE SOLN FOR THE THU-FRI
EVENT ACROSS THE WATERS...STILL TIMING DIFFERENCES AMONG THE
MODELS REMAIN...THEREFOR I WILL ONLY MAKE MINOR CHANGES TO THE
GRIDS FOR THE NEXT PKG...AND NO CHANGE TO WARNING HEADERS.
HOPEFULLY THE 12Z GUIDANCE WILL SHED NEW LIGHT FOR THE AFTERNOON
FCST.

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

OVER THE SHORT TERM...THE NEW 00Z MDLS ARE IN RNSBLY GOOD AGRMT
THAT AS A BROAD CLOSED UPR LOW PERSISTS E OF THE NT2 WTRS THAT AN
ASCD SFC LOW WL DUMBBELL SW TWDS THE NT1 WTRS LATER TODAY...TRACK
S JUST E OF THE NT1 WTRS TONIGHT WHL INTENSIFYING...THEN TURN E
TUE/TUE NITE. THIS LOW/S PASSAGE WL CAUSE A STRENGTHENING NLY
GRADIENT TO DVLP THRUT MUCH OF THE OFSHR WTRS LATE TODAY THRU
TUE...THEN SHIFT EWD TUE NITE. OVERALL BELIEVE THE 00Z GFS
SOLUTION LOOKS REPRESENTATIVE FOR THIS GRADIENT AND AS WAS DONE
PREVLY WL POPULATE OUR SHORT TERM WIND GRIDS WITH ITS 30M BL WINDS
FOR TODAY THRU TUE NITE. BY FCSTG A SLIGHTLY MR RAPIDLY
INTENSIFYING SFC LOW...THE 00Z GFS NOW FCSTS MR WDSPRD ASCD GALES
IN THIS GRADIENT WHICH NOW INCLUDES THE GULF OF MAINE TONITE AND
THEN THE GEORGES BANK WTRS TUE...WHICH IS ALSO SPRTD BY THE 00Z
NAM/GEM. SO OTHERWISE WL NOT BE MAKING ANY OTHER SIG SHORT TERM
CHNGS TO THE PREV OFSHR FCST PACKAGE.

IN THE LONG RANGE...LARGE DISPARITIES CONT BTWN THE 00Z MDLS
DUE TO THEIR DIFFERING FCST EVOLUTION OF A CLOSED UPR LOW DIGGING
TWDS THE E COAST WHICH HAS RESULTED IN POOR RUN-TO-RUN CONTINUITY
IN RGRDS TO BOTH THEIR FCST TRACKS/STRENGTHS OF AN ASCD POTENTIAL
DVLPG SRN STREAM SFC LOW MOVG NE ACRS THE WTRS WED NITE INTO FRI
NITE. ON WED NITE THE 00Z MDLS GNRLY AGREE (EXCEPT THE 00Z GEM
WHICH LOOKS LIKE A TOO SUPPRESSED AND WEAK OUTLIER SOLUTION) THAT
THE DVLPG SFC LOW WL MOVE NE INTO THE SW NT2 WTRS NR THE SE COAST.
THEN VS ITS PREV 18Z RUN...THE 00Z GFS NOW FCSTS ITS CLOSED UPR
LOW TO DIG MR QUICKLY TWDS THE MID ATLC COAST BY LATE THU/THU NITE
WHICH RESULTS IN A TRACK CLOSER TO THE COAST AND A WEAKER SFC LOW
DUE TO IT BCMG VERTICALLY STACKED SOONER. THEN THE 00Z GFS FCSTS
ITS CLOSED UPR LOW AND VERTICALLY STACKED SFC LOW TO TRACK EWD NR
40N MR SLOWLY FRI INTO FRI NITE. THE 00Z GEFS MEAN INDICATES THAT
THE 00Z GFS FCST TRACK IS TOO FAR TO THE NW. THE 00Z UKMET BY NOT
FCSTG ITS UPR TROF TO TRANSITION INTO A CLOSED UPR LOW UNTIL FRI
NITE FCSTS ITS ASCD SFC LOW TO REMAIN WEAKER THAN THE 00Z GFS AND
TRACK SIGLY FURTHER OFSHR THU INTO FRI...THEN TURN MR NWD TWDS
GEORGES BANK AND BCMG VERTICALLY STACKED WITH ITS UPR LOW AND
RAPIDLY INTENSIFYING FRI NITE. THE 00Z ECMWF HAS COME IN WITH A
FCST TRACK THAT IS MR IN LINE WITH THE 00Z GEFS MEAN TRACK AND
LOOKS LIKE A RSNBL COMPROMISE BTWN THE MR NW 00Z GFS AND MR SE 00Z
UKMET FCST TRACKS. ALSO PREFER THE MR CONSISTENT 00Z ECMWF
SOLUTION FOR THE FCST STRENGTH OF THIS LOW. THEREFORE...WITH STIL
LOW FCST CONFIDENCE...PLAN ON POPULATING OUR LONG RANGE FCST WIND
GRIDS WITH THE 00Z ECMWF BL WINDS ON WED THRU FRI NITE...TIME
SHIFTED 6HRS SLOWER FRI/FRI NITE IN DEFERENCE TO THE SLOWER 00Z
GEFS MEAN TRACK. SO SINCE THE 12Z UKMET WAS PREVLY FAVORED FOR
THIS SYSTEM WL BE MAKING SM SIG LONG RANGE CHNGS IN THE NEXT OFSHR
FCST PACKAGE.

SEAS...WITH THE DIFFERENCES BTWN THE TWO MDLS RMNG MINIMAL...WL
USE A 50/50 BLEND OF THE 00Z WAVEWATCH III AND 00Z ECMWF WAM MDLS
FOR TODAY THRU TUE NITE. THEN SINCE THE 00Z ECMWF WL BCM
FAVORED...WL TRANSITION TO ALL 00Z ECMWF WAM FCST SEAS FOR WED
THRU FRI NITE...ALSO TIME SHIFTED 6HRS SLOWER FRI/FRI NITE.

.EXTRATROPICAL STORM SURGE GUIDANCE...N/A.


.WARNINGS...PRELIMINARY.

.NT1 NEW ENGLAND WATERS...
.ANZ800...GULF OF MAINE...
     GALE TONIGHT.
.ANZ805...GEORGES BANK WEST OF 68W...
     GALE POSSIBLE FRI INTO FRI NIGHT.
.ANZ900...GEORGES BANK EAST OF 68W...
     GALE TUE.
     GALE POSSIBLE FRI INTO FRI NIGHT.

.NT2 MID ATLC WATERS...
.ANZ915...HUDSON CANYON TO THE GREAT SOUTH CHANNEL...
     GALE TUE.
     GALE POSSIBLE FRI INTO FRI NIGHT.
.ANZ920...BALTIMORE CANYON TO THE GREAT SOUTH CHANNEL...
     GALE TUE.
     GALE POSSIBLE THU NIGHT INTO FRI NIGHT.
.ANZ905...THE GREAT SOUTH CHANNEL TO THE HAGUE LINE...
     GALE TUE INTO TUE NIGHT.
     GALE POSSIBLE THU NIGHT INTO FRI NIGHT.
.ANZ910...EAST OF THE GREAT SOUTH CHANNEL AND SOUTH OF 39N...
     GALE TUE INTO TUE NIGHT.
     GALE POSSIBLE THU NIGHT INTO FRI NIGHT.
.ANZ825...INNER WATERS FROM BALTIMORE CANYON TO CAPE CHARLES LIGHT...
     GALE POSSIBLE THU NIGHT.
.ANZ828...INNER WATERS FROM CAPE CHARLES LIGHT TO CURRITUCK BEACH LIGHT...
     GALE POSSIBLE THU INTO FRI.
.ANZ925...OUTER WATERS FROM BALTIMORE CANYON TO HATTERAS CANYON...
     GALE POSSIBLE THU INTO FRI NIGHT.
.ANZ830...INNER WATERS FROM CURRITUCK BEACH LIGHT TO CAPE HATTERAS...
     GALE POSSIBLE THU NIGHT INTO FRI.
.ANZ833...INNER WATERS FROM CAPE HATTERAS TO CAPE FEAR...
     GALE POSSIBLE THU NIGHT INTO FRI.
.ANZ930...OUTER WATERS FROM HATTERAS CANYON TO CAPE FEAR...
     GALE POSSIBLE THU NIGHT INTO FRI.
.ANZ835...INNER WATERS FROM CAPE FEAR TO 31N...
     GALE POSSIBLE THU NIGHT.
.ANZ935...OUTER WATERS FROM CAPE FEAR TO 31N...
     GALE POSSIBLE THU NIGHT.

$$

.FORECASTER SHAW/VUKITS. OCEAN PREDICTION CENTER.


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.