Marine Interpretation Message
Issued by NWS

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AGNT40 KWNM 310214
MIMATN

MARINE WEATHER DISCUSSION FOR N ATLANTIC OCEAN
NWS OCEAN PREDICTION CENTER WASHINGTON DC
1014 PM EDT SUN AUG 30 2015

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

THE SAT IMG INDC CONV CLDS OVR THE FAR S-WRN WTRS WITH DENSE
LIGHTNG STRIKES. THE RADAR HAS INDC STRNG TSTMS CELLS OVR THE
S-WRN PARTS. AT 00Z AREA OF HGH PRES DOMINATES THE FRCST REGON
XCPT THE S-WRN PARTS WHERE INLAND TROF LIES JUST W OF THE SRN
REGION. THE PRES GRDNT IS VERY SLCK WITH MAX OBSVD WINDS REACHING
ONLY 15 KT. THE LAST ASCAT PASS WAS AT 1546Z AND HAD MAX WINDS
REACHING 25 KT OVR THE S-WRN AREA IN THE CONV REGIONS. THE SEAS
ARE ARE SMALL PEAKING AT 6 FT OVR THE FAR SRN WTRS AND THE FAR ERN
PARTS OF THE HATTERAS CNYN. ELSEWHERE SEAS RANGE BTWN 2 AND 5 FT. BOTH
NWW3 AND ECMWFWV MDLS FIT WELL WITH THE OBSVD SEAS PATTERN AND HV
BEEN QUITE CONSSTNT AND SO WILL CONTINUE WITH WNA.

AN UPPRLLVL RIDGE HAS DOMINATED THE REGION WITH JUST VERY LITTLE
ENERGY EMBDD IN AN UPPRLVL TROF BARELY TOCHING THE NRN WTRS. THERE
IS SOME LOCALLY INDCD ENERGY ALSO INLAND W OF THE SRN WTRS THAT
WILL SHIFT INTO THE WTRS IN THE SHORT TERM...ALREADY IMPACTING THE
S-WRN WTRS. THIS ENRGY WILL BE SO LITTLE THAT AN UPPRLVL RIDGE
WILL SWEEP IT EAST AND THE REGION WILL AGAIN REMAIN WITH ALMOST NO
ENERGY AND WILL BE LIKE THAT IN THE XTNDD PRD. SINCE THERE ARE NO
INDC OF SIG ENRGY THAT WILL FORCE CHNGS TO THE CURR SYNOP
SENARIO...SHUD CONTINUE WITH MEAGRE WX OVR THE ENTIRE FCST WTRS.

THE GLBL MDLS ARE STILL IN GUD AGRMNT IN THE SHORT TERM AND THEY
HV JUST MNR DIFFS IN THE XTNDD PRD BUT THAT WILL NOT CHNG THE
SYNOP PATTERN. WILL CONTINUE FCST WITH GFS. IN THE SHORT TERM HGH
PRES WILL REMAIN OVR THE REGION WITH VERY SLCK PRES GRDNT AND SO
WINDS WIL REMAIN BELOW GALE FORCE THRESHOLD THRU THE FCST PRD.

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

OVER THE SHORT TERM...THE NEW 12Z MDLS SHARE SMLR FCST TIMING FOR
A COLD FRONT TO MOV TO THE NEW ENGLD COAST LATE MON...PUSH SSE
ACRS THE NT1 WTRS MON NITE...THEN CONT SLOWLY ACRS THE NRN NT2
WTRS TUE/TUE NITE WHL WKNG. IN RGRDS TO THE FCST GRADIENTS ASCD
WITH THIS FROPA BLV A COMPROMISE BTWN THE STRONGER 12Z NAM/GFS AND
WEAKER 12Z UKMET/ECMWF LOOKS RSNBL AND AS A RESULT WL WULD THE MAX
ASCD WINDS GNRLY IN THE 15-20 KT RANGE. FURTHER S... UNLIKE ITS
PREV RESPECTIVE RUNS...THE 12Z GFS NOW FCSTS A WEAK SFC LOW TO
FORM ALONG A CSTL TROF OFF THE CAROLINA COASTS MON NITE...THEN
TRACK SLOWLY ENE TUE/TUE NITE WITH WEAK ASCD GRADIENTS (WITH MAX
WINDS NO HIGHER THAN 15 OR 20 KT). WHETHER THIS IS THE REMNANTS OF
WHAT WAS T.S. ERIKA IS DEBATABLE BUT IT COULD CERTIANLY BE CAUSED
BY ITS LEFTOVER VORTICITY. WL DISREGARD THE 12Z GLOBAL GEM
SOLUTION WHICH FCSTS A SMLR BUT SIGLY STRONGER (WITH SM GALE FORCE
ASCD BL WINDS) AND SMWHT MR PROGRESSIVE SFC LOW. THE 12Z UKMET ON
THE OTHER HAND JUST FCSTS A WEAK SFC TROF OFF THE SE COAST TUE/TUE
NITE. THE 12Z ECMWF IS NOW SMLR TO THE 12Z GFS BUT FCSTS AN
EQUALLY WEAK SFC LOW TO DVLP ALONG THE CSTL TROF FURTHER N INVOF
HAT CNYN MON NITE...THEN DRIFT SLOWLY ESE SMWHT FURTHER N AND
SLIGHTLY FASTER THAN THE 12Z GFS TRACK. WITH LOW FCST CONFIDENCE
IN THE TRACK OF THE FCST SFC LOW OVER THE SRN NT2 WTRS...FOR NOW
SINCE IT DOES HV SPRT FM THE 12Z GEFS MEAN AND THE 12Z ECMWF...WL
POPULATE OUR SHORT TERM FCST WIND GRIDS WITH THE 12Z GFS 10M BL
WINDS THRU TUE NITE WITH SM ADDITIONAL EDITS IN DEFERENCE TO THE
12Z ECMWF. SO OTHER THAN SM CHNGS TO THE FCST WIND DIRECTIONS FOR
THE LITE WINDS ACRS THE SRN NT2 WTRS...DO NOT PLAN ON MAKING ANY
SHORT TERM CHNGS TO THE PREV OFSHR FCSTS.

IN THE LONG RANGE...THE 12Z GFS FCSTS ITS WEAK SFC LOW TO MEANDER
ESE ACRS THE SRN NT2 WTRS WED/WED NITE...THEN PASS SE OF THE WTRS
THU. FURTHER N THE 12Z GFS/UKMET/ECMWF GNRLY AGREE THAT A VERY
WEAK COLD FRONT WL MOVE OFSHR INTO THE GULF OF MAINE WED
NITE...DRIFT EVER SO SLOWLY S ACRS THE RMNG NT1 AND NRN NT2 WTRS
THU/THU NITE...THEN DSIPT FRI AS A HIGH PRES RIDGE BLDS OFSHR INTO
THE NT1 WTRS FRI/FRI NITE. THO DURING THIS TIMEFRAME THE 12Z
GFS/UKMET/ECMWF DIFFER ON THEIR FCST TRACKS OF THE WEAK SFC LOW SE
OF THE SRN NT2 WTRS...OVERALL THEY FCST SMLR GRADIENTS...ESPECLY
THE 12Z GFS/UKMET WHICH IS SPRTD BY THE 12Z GEFS MEAN. THEREFORE
WL CONT TO POPULATE OUR LONG RANGE FCST WIND GRIDS WITH THE 12Z
GFS 10M BL WINDS WED THRU FRI NITE.

SEAS...THE 12Z WAVEWATCH III HAS INITIALIZED THE CURRENT SEAS
SLIGHTLY BETTER THAN THE 12Z ECMWF WAM. THEREFORE SINCE THE 12Z
GFS SOLUTION WL BE FAVORED...WL POPULATE OUR FCST WAVE GRIDS WITH
THE 12Z WAVEWATCH III THRU FRI NITE (WHICH OVERALL NEVER VARY MR
THAN 1-2 FT FM THE SMLR 12Z ECMWF WAM FCST SEAS).

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


.WARNINGS...PRELIMINARY.

.NT1 NEW ENGLAND WATERS...
     NONE.

.NT2 MID ATLC WATERS...
     NONE.

$$

.FORECASTER MUSONDA/VUKITS. OCEAN PREDICTION CENTER.


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