Marine Interpretation Message
Issued by NWS

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AGNT40 KWNM 310132
MIMATN

MARINE WEATHER DISCUSSION FOR N ATLANTIC OCEAN
NWS OCEAN PREDICTION CENTER WASHINGTON DC
932 PM EDT MON MAY 30 2016

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

THE LAST FEW VIS SATELLITE IMAGES SHOW POST-TROPICAL BONNIE STILL
ALONG THE COAST OF SOUTH CAROLINA...NEARLY STATIONARY. BUOY
REPORTS OFF THE COAST SHOW NO MORE THAN ABOUT 10 KT INVOF PT
BONNIE...AND HIGHEST WINDS UP TO ABT 20 TO 25 KT APPEAR TO BE
FURTHER E ALONG A WK TROF OVR THE OUTER NT2 WATERS. THE GFS HAS
BEEN THE MOST CONSISTENT SOLN FOR BONNIE...AND HAS BEEN SLOWER
THAN THE REST OF THE GLOBAL MODELS WITH BRINGING THE REMNANT LOW
NE ALONG THE COAST. THE PREV FCST HAD FAVORED THE GFS FOR THE
FCST...AND ATTM AM INCLINED TO STAY WITH IT FOR PT BONNIE IN THE
UPDATE PKG DUE TO IT VERIFYING BETTER.

OTRW...THE GOES WV IMGRY INDC AN UPR RDG OVR THE WRN ATLC...AND A
WK SHORTWAVE TROF MOVING THROUGH SE CANADA TWD THE COAST. THE
12Z/18Z MDLS ALL INDC THE ASSOC WK FRNTL BNDRY WL TRAVERSE TNGT
INTO TUE...FLWD BY A SECOND WK SYSTEM TUE NGT INTO WED. THE 12Z
GFS/ECWMF HAVE BEEN GUD AGRMT ON THE TMG OF THESE SYSTEMS...AND
THE GFS HAS CONSISTENLY INDC WINDS TO 25 KT IN THE SW FLOW AHEAD
OF THE FIRST BNDRY TNGT. THE PREV FCST HAD 20 KT FOR TNGT...WHICH
RSNBL WITH THE WEAK FRNT...AND THE VRY STABLE ENVIRONMENT OVER THE
SHELF WATERS...SO WL CONT ALONG THOSE LINES IN THE UPDATE PKG.

IN THE EXTENDED...PT BONNIE IS EXPECTED TO MOVE SLOWLY E THROUGH
THE NRN NT2 WATERS THU INTO FRI ALONG THE AFOREMENTIONED WEAK
SECOND FRONTAL BNDRY...AS HIGH PRES BUILDS OVER NT2 BEHIND IT. THE
12Z/18Z GFS INDC ANOTHER VERY WEAK SYSTEM WL MOVE INTO NT1
SAT...AND THE 12Z ECMWF AGREES SOMEWHAT WELL ON IT. THE PREV FCST
STAYED WITH THE GFS THRU THE EXTENDED PERIOD...AND ATTM STILL SEEMS
RSNBL...SO WL CONT WITH IT FOR THE RMNDR OF THE FCST PD.

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

OVER THE SHORT TERM...AN EARLIER 1529Z HI RESOLUTION ASCAT-B
SCATTEROMETER PASS CONFIRMED THAT MAX WINDS ASCD WITH POST-
TROPICAL BONNIE WERE UP TO 20-25 KT...HIGHEST WELL NE OF THE
CENTER IN THE VCNTY OF THE GULF STREAM OFF CP HATTERAS. IN GNRL
THE NEW 12Z MDLS FCST POST-TROPICAL BONNIE NOW OVER ERN S CAROLINA
TO TRACK EVER SO SLOWLY NE TO THE VCNTY OF CP HATTERAS BY THU
MORNING. IN RGRDS TO THE FCST TRACK OF THIS LOW...THE 12Z UKMET
LOOKS TO BCM A LTL TOO FAR S LATE IN THE SHORT TERM. WOULD INSTEAD
FAVOR THE MR CONSISTENT 12Z GFS TRACK WHICH KEEPS THE LOW CLOSER
TO THE COAST (WHICH IS MR IN LINE WITH THE LAST NHC ADVSRY) THAN
FCST BY THE 12Z UKMET/ECMWF. IN RGRDS TO THE FCST GRADIENTS ASCD
WITH THIS SYSTEM...PER A CONSENSUS OF THE 12Z MDLS A RANGE OF
15-20 KT...TO AT MOST 25 KT...STIL LOOKS REPRESENTATIVE. OTHERWISE
OVER THE SHORT TERM...THE 12Z MDLS SHARE SMLR TIMING FOR A COLD
FRONT TO MOVE OFSHR INTO THE NRN WTRS LATE TONITE/TUE WHL WKNG.
THEN WULD FAVOR A BLENDED 12Z GFS/UKMET/ECMWF SOLUTION FOR ANOTHER
WEAK COLD FRONT TO PUSH S ACRS THE NT1 AND NRN NT2 WTRS TUE NITE
INTO WED...AND THEN BCM QSTNRY ACRS THE N CNTRL NT2 WTRS WED NITE.
THEREFORE MAINLY AS A COMPROMISE FOR THE SWLY PREFRONTAL GRADIENTS
ASCD WITH THE TWO COLD FROPAS...PLAN ON POPULATING OUR SHORT TERM
FCST WIND GRIDS WITH A 50/50 BLEND OF THE 12Z GFS 30M AND 10M BL
WINDS FOR TONITE THRU WED NITE...WITH THESE WINDS THEN CAPPED AT
20 KT ACRS THE COLDER SHELF WTRS N OF THE GULF STREAM SMLR TO THE
PREV OFSHR FCST PACKAGE.

IN THE LONG RANGE...THE 12Z GFS CONTS THE TREND OF ITS PREV 06Z
RUN IN FCSTG POST-TROPICAL BONNIE TO TRACK MR SLOWLY ENE ACRS THE
CNTRL/NERN NT2 WTRS LATE THU INTO SAT...WHICH IS MR IN LINE WITH
THE LAST NHC ADVSRY. THE 12Z GEM LOOKS TOO PROGRESSIVE WITH ITS
FCST OF BONNIE WHL THE 12Z UKMET TRACK CONTS TO LOOK LIKE A SRN
OUTLIER. THE 12Z ECMWF DISSIPATES ITS REMNANT LOW BY FRI NITE. SO
SINCE IT OFFERS THE MOST CONSISTENT SOLUTION FOR BONNIE...PLAN ON
POPULATING WITH THE SLIGHTLY STRONGER 12Z GFS 30M BL WINDS FOR THU
THRU SAT NITE.

SEAS...OVERALL THE 12Z WAVEWATCH III AND 12Z ECWMF WAM MDLS HAVE
BOTH INITIALIZED THE CURRENT SEAS RSNBL WELL. WITH THIS IN MIND
AND WITH THEIR ASCD GLOBAL MDL SOLUTIONS BEING SMLR...WL POPULATE
OUR FCST WAVE GRIDS WITH A 50/50 BLEND OF THE TWO MDLS FOR TONIGHT
THRU TUE NITE. THEN SINCE THE 12Z GFS SOLUTION WL BCM
PREFERRED...WL TRANSITION TO ALL 12Z WAVEWATCH III FCST SEAS FOR
WED THRU SAT NITE.

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

.WARNINGS...PRELIMINARY.

.NT1 NEW ENGLAND WATERS...
     NONE.

.NT2 MID ATLC WATERS...
     NONE.

$$

.FORECASTER KELLS/VUKITS. OCEAN PREDICTION CENTER.



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