Marine Interpretation Message
Issued by NWS

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000
AGNT40 KWNM 220217
MIMATN

MARINE WEATHER DISCUSSION FOR N ATLANTIC OCEAN
NWS OCEAN PREDICTION CENTER WASHINGTON DC
917 PM EST SUN DEC 21 2014

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

THE SAT IMG SHOW MORE CONVCTN OVR THE SRN WTRS ASCTD WITH A WRM
FRNT BUT NO LIGHTNG. THE RADAR HAS DSPTNG TSTMS CELLS OVR THE FAR
S-WRN WTRS. AT 00Z LOW PRES 1015 MB OVR WTRS ADJ TO GA HAS A WRM
FRNT STRTCHNG E ACRS THE FAR SRN PORTIONS. INLAND HGH PRES OVR
QUEBEC XTNDS A RIDGE SW THRU NY AND THE MID ATLC STATES INTO THE
S-ERN STATES. THE PRES GRDNT IS SLACK AND THE MAX OBS WINDS ARE 25
KT OVR THE SRN WTRS. THE LAST RAPID-SCAT PASS OVR THE REGION IS
STILL THE ONE ABOUT 1420Z DESCRIBED BELOW IN THE PREVIOUS
DISCUSSION SECTION. THE SEAS RANGE BTWN 2 AND 6 FT OVR MOST OF THE
REGION XCPT THE SRN WTRS WHERE THEY PEAK AT 8 FT. THE NWW3 MULTI
GRID WV MDL FITS FAIRLY WELL WITH THE SEAS PATTERN AND SO IS THE
ECMWFWAVE AND BOTH WV MDLS ARE IN AGRMNT IN THE SHORT TERM.

THERE IS JUST A FEW SPOTS OF LOCALLY GENERATED ENRGY IN A FAIRLY
WK RIDGE ALOFT. UPPLVL DIFFLENCE OVR CANADA WILL ALLOW MORE ENERGY
TO SPILL BACK INTO THE TROF TO THE W AND THAT ENERGY WILL COMBINE
WITH THE ONE STREAMING FRM THE W AND DVLP A FAIRLY DEEP UPPRLVRL
TROF THAT WIL RESULT INTO A CLSD LOW THAT WILL PUSH A STRNG FRNT
INTO THE REGION IN THE XTNDD PRD. HENCE THE CURR WRNGS IN THE FRCT
IN THE XTNDD PRD WIL BE RETAINED.

THE GLBL MDLS HV INTIALIZED WELL AND THEY ARE IN DECENT AGRMNT IN
THE SHORT TERM WIL EXPLORE THE DIFFS IF ANY IN THE XTNDD PRD IN
THE NEXT MORNING DISCUSSION. FOR NOW WIL STAY WITH GFS IN THE
SHORT TERM AND WILL RETAIN MOST OF THE FCST AS FROM THE PREVIOUS
ISSUANCE. IN THE SHORT TERM THE HGH PRES OVR CANADA WIL MV SE
WHILE THE LOW PRES OVR THE SRN WTRS WILL MOVE NE AND LIFT THE WRM
FRNT ACRS THE SRN WTRS INTO THE NRN WTRS.

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

1420Z HIGH RESOLUTION ASCAT-A OVERPASS INDICATED E WINDS 20 TO
25 KT N OF WARM FRONT OVER CAPE FEAR TO 31N OFFSHORE WATERS.
WINDS ARE LIKELY SLIGHTLY HIGHER CLOSER TO COAST BUT DID NOT
HAVE ASCAT TO CONFIRM. HOWEVER FRYING PAN SHOALS BUOY 41013
INCREASED TO 23 G 29 KT LAST HOUR. 12Z MODELS ARE IN GOOD
AGREEMENT THAT WEAK SFC LOW WILL SLOWLY DRIFT N OFF SC/NC COASTS
TONIGHT AND MON...ALONG VA CAPES AND DELMARVA COAST MON NIGHT
AND TUE BEFORE DISSIPATING SRN NJ COAST TUE NIGHT. GIVEN ASCAT
PASS MENTIONED ABOVE AM CONTINUING TO FAVOR THE HIGHER GFS 30M
WINDS WHICH ADVERTISE WINDS ASSOCIATED WITH LOW/WARM FRONT TO 25
OR 30 KT TONIGHT INTO EARLY TUE. 12Z GFS/UKMET/GLOBAL GEM AND
00Z ECMWF ARE ALL IN GOOD AGREEMENT WITH TIMING OF LOW AND WARM
FRONT. 12Z PARALLEL GFS WAS A BIT FASTER WITH LOW THAN ABOVE
MODEL CONSENSUS. ASCAT ALSO INDICATED A WEAK SFC REFLECTION
CENTERED JUST S OF ERN LONG ISLAND ASSOCIATED WITH UPPER SHORTWV
MOVING E THROUGH NEW ENGL WATERS. ASCAT RETURNED SOME WINDS TO
20 KT OVER COASTAL WATERS WHICH IS SLIGHLY HIGHER THAN MODELS
INDICATING.

MODELS CONTINUE IN AGREEMENT THAT SHARPLY AMPLIFIED UPPER TROF
WILL MOVE E OF MS VALLEY WED AND APPROACHING APPALACHIANS WED
NIGHT. OVER LAST COUPLE DAYS MODELS HAVE BACKED OFF SOMEWHAT
WITH STRENGTH OF WINDS OFFSHORE AHEAD OF COLD FRONT. GFS AND
GFSP REMAIN ON STRONGER SIDE OF GUIDANCE. 12Z UKMET WAS WEAKER
WITH WINDS WHEN COMPARED TO PREVIOUS RUN. IN ADDITION THERE
CONTINUE TO BE TIMING DIFFERENCES WITH FRONT MOVING OFFSHORE WED
NIGHT. 12Z ECMWF WAS CONSISTENT WITH ITS PREVIOUS RUN AND ALONG
WITH 12Z GLOBAL GEM ARE FASTER THAN 12Z GFS/GFSP. 12Z UKMET
TRENDED MUCH SLOWER FROM ITS PREVIOUS RUN AND WILL BE
DISREGARDED. AM FAVORING A BLENDED ECMWF/GFS TIMING. AS FAR AS
WINDS PREFER 12Z ECMWF AND HOW IT HANDLES THE S TO SW WINDS AS
IT BETTER CAPTURES ENHANCED WINDS OVER GULF STREAM. WILL FURTHER
ENHANCE WINDS OVER GULF STREAM BY 10 PERCENT OR SO WED NIGHT AND
THU. SO WILL USE 12Z ECMWF BUT ADJUST TIMING OF COLD FRONT ABOUT
THREE HOURS SLOWER. HAVE MODERATE FORECAST CONFIDENCE WITH GALES
AHEAD OF COLD FRONT WED NIGHT AND THU...EXCEPT HIGHER CONFIDENCE
WITH GALES FORECAST OVER GULF STREAM. PER GFS/ECMWF PLAN TO
CARRY SOME GALES BEHIND COLD FRONT MAINLY OVER OUTER WATERS N OF
BALTIMORE CANYON THU INTO EARLY THU NIGHT. GFS/ECMWF ARE STILL
IN PRETTY GOOD AGREEMENT AT WEEKS END WITH HIGH PRES RIDGE
RAPIDLY MOVING OFF THE COAST FRI FOLLOWED BY ANOTHER COLD FRONT
APPROACHING FRI NIGHT. BOTH 12Z GFS AND 12Z ECMWF INDICATE SW
WINDS INCREASING TO 25 KT N OF BALTIMORE CANYON FRI NIGHT.

.SEAS...AT 18Z HAD TWO 7 FT REPORTS AND AN 8 FT REPORT OFFSHORE
S OF CAPE HATTERAS WHICH SUGGESTS 12Z MULTIGRID WAVEWATCH III
CONTINUE TO BE A FT OR SO TOO LOW WITH SIG WV HGTS. 12Z ECMWF
WAVE MDL IS SLIGHTLY HIGHER THAN 12Z MWW3 N OF WARM FRONT
TONIGHT INTO MON NIGHT. USED A 50/50 BLEND OF ABOVE MODELS
TONIGHT THROUGH TUE. THEN WITH PREFERENCE FOR ECMWF WINDS TUE
NIGHT THROUGH FRI NIGHT USED A 80 PERCENT 12Z ECMWF/20 PERCENT
12Z MWW3 BLEND.

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


.WARNINGS...PRELIMINARY.

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

.NT2 MID ATLC WATERS...
.ANZ820...HUDSON CANYON TO BALTIMORE CANYON...
     GALE POSSIBLE WED NIGHT INTO THU.
.ANZ915...HUDSON CANYON TO THE GREAT SOUTH CHANNEL...
     GALE POSSIBLE WED NIGHT INTO THU NIGHT.
.ANZ920...BALTIMORE CANYON TO THE GREAT SOUTH CHANNEL...
     GALE POSSIBLE WED NIGHT INTO THU NIGHT.
.ANZ905...THE GREAT SOUTH CHANNEL TO THE HAGUE LINE...
     GALE POSSIBLE THU INTO THU NIGHT.
.ANZ910...EAST OF THE GREAT SOUTH CHANNEL AND SOUTH OF 39N...
     GALE POSSIBLE WED NIGHT INTO THU NIGHT.
.ANZ825...INNER WATERS FROM BALTIMORE CANYON TO CAPE CHARLES LIGHT...
     GALE POSSIBLE WED NIGHT.
.ANZ828...INNER WATERS FROM CAPE CHARLES LIGHT TO CURRITUCK BEACH LIGHT...
     GALE POSSIBLE WED NIGHT.
.ANZ925...OUTER WATERS FROM BALTIMORE CANYON TO HATTERAS CANYON...
     GALE POSSIBLE WED NIGHT INTO THU.
.ANZ830...INNER WATERS FROM CURRITUCK BEACH LIGHT TO CAPE HATTERAS...
     GALE POSSIBLE WED NIGHT.
.ANZ833...INNER WATERS FROM CAPE HATTERAS TO CAPE FEAR...
     GALE POSSIBLE WED NIGHT INTO THU.
.ANZ930...OUTER WATERS FROM HATTERAS CANYON TO CAPE FEAR...
     GALE POSSIBLE WED NIGHT INTO THU.
.ANZ835...INNER WATERS FROM CAPE FEAR TO 31N...
     GALE POSSIBLE WED INTO THU.
.ANZ935...OUTER WATERS FROM CAPE FEAR TO 31N...
     GALE POSSIBLE WED NIGHT INTO THU.

$$

.FORECASTER MUSONDA/CLARK. OCEAN PREDICTION CENTER.


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