Marine Interpretation Message
Issued by NWS

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000
AGNT40 KWNM 290144
MIMATN

MARINE WEATHER DISCUSSION FOR N ATLANTIC OCEAN
NWS OCEAN PREDICTION CENTER WASHINGTON DC
944 PM EDT MON JUL 28 2014

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

LOW PRES WAS NR MAINE AND LIFTING N WHILE INTENSIFYING. AN ASSOC CD
FNT IS MOVG OFFSHR WITH HVY CONVECTION INADVOF FNT OVR THE CNTRL
AND SRN MID ATLC WTRS. THERE WAS HVY CONVECTION ALSO INADVOF TROF
MOVG E OVR THE FAR ERN AREAS OF SRN NEW ENGLAND WTRS INTO THE NRN
MID ATLC WTRS. THERE WERE SVRL SHIP OBS WITH GALE FORCE WITH WINDS
GUSTING TO AS HIGH AS 45 KT WITH A OBS OVR THE ERN AREAS OF FAR
NRN MID ATLC WTRS. CD FNT MOVS E OVR THE WTRS AND STALLS TUE AND TUE
NGT WITH WK LOW PRES DVLPG OFF THE SE COAST AND MOVG NE. 18Z GFS
APRS TO BE FASTER TO BRING N TO NW WINDS ACRS THE MID ATLC WTRS
WED INSTEAD OF KEEPING S TO SWLY FLW. ATTM WL LV AS IT IS AND
MAKE ANY NEEDED CHANGES WITH 00Z MDL GUID WHEN IT COMES IN. OTW
CUR GRIDS LOOK OK THRU FCST PD.

SEAS...18Z WWIII AND ECMWF SEEM TO BE INIT WELL AND SHOW ENHANCED
SEAS WHERE THERE HVY CONVECTION. MDL GUID LOOKS RSNBL THRU THE
FCST PD AND WL STAY WITH GRIDDED DATA FM EARLIER FCST PACKAGE.

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

SUMMARY...A STRONG LOW PRES AREA OVER NEW ENGLAND IS MOVING N. A
COLD FRONT EXTENDS SW FROM THE LOW PRES CENTER THIS AFTN. AS THE
LOW MOVES N...THE FRONT WILL PUSH E AND SE INTO THE OFF WTRS TNGT
THRU TUE. A WEAK LOW IS EXPECTED TO FORM ALONG THE SLOW-MOVG COLD
FRONT OFF THE S CAROLINA COAST BY EARLY TUE. THE LOW IS EXPECTED
TO REMAIN WEAK AND TRACK SLWLY N AND NE THRU WED INTO THU AS THE
FRONT BECOMES NEARLY STATIONARY ACROSS THE WTRS AND WEAKENS. THE
MAIN CONCERN IS LKLY TO CONT TO BE THE LOCALLY HVY TSTMS ASSOC
WITH THE FRONT OVR THE OFF WTRS DURING THE NEXT FEW DAYS. THE
LATEST SATELLITE AND LIGHTNING DATA SHOWS VRY HVY TSTMS OVR
GEORGES BANK THIS AFTN MOVG NE. LOCALLY VRY STRONG WINDS WITH
GUSTS EXCEEDING GALE FORCE ARE LKLY IN AND NR THE HEAVIER TSTMS
TNGT INTO TUE. THE MODERATELY STRONG S-SW WIND FIELD CURRENTLY
OVR MOST OF THE OFF WTRS WILL PERSIST INTO TNGT...AND THEN
DIMINISH BY TUE OVR MOST OF THE WTRS AS THE COLD FRONT MOVES E
AND SE INTO THE WTRS. MAX WINDS TO 30 KT STILL APPEAR LKLY AHEAD
OF THE FRONT TNGT MAINLY OVR ERN AND NE NT2 OFF WTRS NR AND E OF
THE GULF STREAM. A MID-AM ASCAT PASS INDICATED MAX WINDS NR 25 KT
IN THESE AREAS ALREADY THIS MORNING. CONDITIONS WILL LKLY IMPROVE
OVR MOST OF THE OFF WTRS BY MID TO LATE WK INTO NEXT WKND AS THE
FRONT CONTINUES TO WEAKEN AND DRIFT W AS HIGH PRES BUILDS TO THE
SE OF NEWFOUNDLAND.

MODELS...THE 12Z GFS CONTINUES TO REMAIN CONSISTENT AND IS IN VRY
GUD AGREEMENT WITH THE 12Z UKMET...CANADIAN...AND ECMWF MDLS. WE
WILL REMAIN CLOSE TO THE 12Z GFS FOR THE AFTN PACKAGE...AND CONT
TO USE 30M WINDS NR AND S OF THE GULF STREAM TNGT INTO TUE WHERE
THE STRONGER WINDS ARE MIXING DOWN CURRENTLY. ELSEWHERE AND OTW
WE WILL MAINLY BE USING THE 10M GFS WINDS THRU SAT NGT OVR THE
OFF WTRS. AGAIN...MUCH HIGHER WINDS EXCEEDING GALE FORCE WILL BE
LKLY IN AND NEAR HVY TSTMS OVR THE OFF WTRS DURING THE NEXT FEW
DAYS.

SEAS...THE 12Z MWW3 MDL GUID APPEARS TO HAVE INITIALIZED TOO HIGH
MAINLY OVR WTRS N OF THE GULF STREAM...NRN NT2 AND NT1 OFF
WTRS...PER THE LATEST OBS AND ALTIMETER DATA. THE 12Z ECMWF WAM
APPEARS TO HAVE INITIALIZED A BIT BETTER SO WE WILL BE USING THE
12Z ECMWF WAM WV GUID INITIALLY FOR THE AFTN FCST PACKAGE. WE
WILL TWEAK GRIDS AS NEEDED TO FIT WITH THE OBS NOTED JUST PRIOR
TO FCST ISSUANCE. OTW...BY WED OR SO...BOTH MDLS APPEAR SIMILAR
SO WE WILL BE SWITCHING BACK TO THE MWW3/WNA WW3 MDL DURING
WED...AND THEN CONT TO USE THE WW3 MDL GUID INTO THE UPCOMING
WKND. OVRALL... NO MAJOR CHANGES FROM THE PREV FEW OPC FCSTS FOR
THE AFTN PACKAGE. MUCH HIGHER SEAS WILL BE FOUND IN AND NR THE
HEAVIER TSTMS THRU TNGT INTO TUE.

.EXTRATROPICAL STORM SURGE GUIDANCE...NA


.WARNINGS...PRELIMINARY.

.NT1 NEW ENGLAND WATERS...
     NONE.

.NT2 MID ATLC WATERS...
     NONE.

$$

.FORECASTER ROWLAND/MILLS. OCEAN PREDICTION CENTER.



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