000
AGXX40 KNHC 201756
MIMATS

MARINE WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
156 PM EDT FRI SEP 20 2013

MARINE WEATHER DISCUSSION FOR THE GULF OF MEXICO...CARIBBEAN
SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND
64W...AND THE SW N ATLANTIC INCLUDING THE BAHAMAS.

...GULF OF MEXICO...

MODEL PREFERENCE: OFFICIAL FORECAST BLENDED WITH LATEST GFS. NWPS
USED FOR WAVE PARAMETERS. MEDIUM CONFIDENCE.

1002 MB LOW PRES IS IN THE SW CENTRAL GULF NEAR 22.5N96.5W.
CONVECTION IS CONFINED TO THE SE AND S QUADRANTS WITH FRESH TO
STRONG WINDS AND SEAS TO 8 FT WITHIN 300 NM IN THE NE SEMICIRCLE.
THIS LOW IS FORECAST TO MERGE WITH THE FRONT SE OF BROWNSVILLE
TEXAS BY SAT MORNING WITH ASSOCIATED WINDS AND SEAS RELATED TO THE
ORIGINAL LOW PRIOR TO FRONTAL ACQUISITION QUICKLY DIMINISH/
SUBSIDE. CONDITIONS ARE ONLY MARGINALLY FAVORABLE FOR DEVELOPMENT
AND THE CHANCE FOR DEVELOPMENT INTO A TROPICAL CYCLONE HAS BEEN
SIGNIFICANTLY LOWERED DURING THE PAST 24 HOURS.

OTHERWISE...LOW LEVEL SOUTHEASTERLY FLOW IS UNUSUALLY FEEDING UP
ALL THE WAY FROM THE WESTERN CARIBBEAN AND NORTHERN SOUTH AMERICA
ACROSS THE BASIN INTO THE LOWER MISSISSIPPI VALLEY...WITH MODERATE
TO FRESH WINDS AT THE SURFACE...EXCEPT LIGHT TO MODERATE E OF 87W.
SEAS ARE 1-3 FT IN THE NE GULF AND 4-6 FT ELSEWHERE OUTSIDE OF THE
INFLUENCE OF THE LOW PRES AREA.

A COLD FRONT WILL APPROACH THE TEXAS COAST SAT MORNING...MOVING
OFFSHORE AND REACHING FROM 30N93W TO 26N96W TO 21N97W SAT EVENING
...THEN FROM 29N92W TO 26N95W TO 21N95W TO 19N96W SUN MORNING
WHERE IT WILL STALL THROUGH MON. FRESH TO STRONG WINDS AND
BUILDING SEAS TO 8 FT ARE INITIALLY EXPECTED BEHIND THE FRONT. THE
FRONT WILL THEN DRIFT E TO THE CENTRAL GULF WATERS TUE INTO WED...
PERHAPS STALLING AGAIN IN THE E GULF BY THE END OF THE WEEK AS
HIGH PRES IN THE ATLC ATTEMPTS TO BLOCK ANY FORWARD PROGRESS.

...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN
55W AND 65W...

MODEL PREFERENCE: OFFICIAL FORECAST BLENDED WITH LATEST GFS. NWPS
USED FOR WAVE PARAMETERS. HIGH CONFIDENCE.

A VERY BROAD AND WEAK PRES GRADIENT IS IN PLACE ACROSS THE
CARIBBEAN BASIN WITH LIGHT TO MODERATE WINDS...LOCALLY FRESH IN
THE NW CARIBBEAN. SEAS ARE 1-3 FT IN THE E CARIBBEAN AND 3-5 FT
IN THE CENTRAL AND W CARIBBEAN. THESE CONDITIONS ARE FORECAST TO
PERSIST THROUGH THE MAJORITY OF THE WEEKEND...EXCEPT IN PORTIONS
OF THE NW CARIBBEAN SE OF THE YUCATAN CHANNEL WHERE BROAD LOW PRES
MAY TIGHTEN THE GRADIENT JUST ENOUGH TO ALLOW FOR A SMALL AREA OF
FRESH TO STRONG WINDS AND SEAS TO 8 FT. HIGH PRES BUILDS/
STRENGTHENS N OF THE AREA LATE SUN THROUGH EARLY NEXT WEEK WHICH
WILL INCREASE TRADES TO FRESH TO STRONG IN THE CENTRAL CARIBBEAN
WITH MODERATE TRADES ELSEWHERE.

IN THE TROPICAL N ATLC...1014 MB LOW PRES IS NEAR 14N55W WITH AN
ATTENDANT TROUGH FROM 19N52W THROUGH THE LOW TO 10N56W. LIGHT TO
MODERATE MAINLY E-SE WINDS...EXCEPT VARIABLE NEAR THE LOW...AND
3-5 FT SEAS DOMINATE THE OFFSHORE WATERS. THE SURFACE FEATURES
WILL DRIFT W THIS WEEKEND...BECOMING ILL-DEFINED BY EARLY MON AS
THEY APPROACH THE E CARIBBEAN. MODERATE E-SE WINDS AND 3-5 FT SEAS
WILL PERSIST THROUGH AT LEAST TUE WITH RIDGING N-NE OF THE WATERS.

...SW N ATLANTIC INCLUDING THE BAHAMAS...

MODEL PREFERENCE: OFFICIAL FORECAST BLENDED WITH GFS. NWPS USED
FOR WAVE PARAMETERS. MEDIUM TO HIGH CONFIDENCE.

1010 MB LOW PRES IS NEAR 27N64W WITH A TROUGH EXTENDING TO THE SW
THROUGH 23N70W TO N CENTRAL CUBA. ACTIVE CONVECTION IS TO THE E OF
THE LOW AND TROUGH ACROSS THE AREA N OF 21N. LIGHT TO MODERATE
WINDS DOMINATE THE BASIN...EXCEPT IN THE NW SEMICIRCLE OF THE LOW
WHERE FRESH TO STRONG WINDS AND SEAS TO 8 FT ARE SETTING UP.
ALSO...A REINFORCING FRONTAL TROUGH IS NW OF THE SOUTHERN TROUGH
WITH AN AREA OF FRESH TO STRONG WINDS AND 7-9 FT SEAS FROM 28N TO
30N BETWEEN 73W AND 77W. SEAS OF 4-6 FT ARE OUTSIDE OF THE
BAHAMAS...WITH THE TYPICAL 1-3 FT W/INSIDE OF THE BAHAMAS...
ALTHOUGH SOME N-NE SWELL CONTINUES TO FEED DOWN THROUGH THE AREA
BETWEEN FLORIDA AND THE BAHAMAS.

THE LOW AND TROUGH WILL SHIFT E OF THE AREA THROUGH SAT. HIGH PRES
RIDGING WILL BUILD ACROSS THE BASIN FROM THE CENTRAL ATLC THROUGH
SUN...HOLDING ACROSS THE SOUTHERN WATERS THROUGH EARLY NEXT WEEK
WHILE ERODING IN THE NORTHERN WATERS AS A COLD FRONT APPROACHES
THE NW PORTION. THIS FRONT IS FORECAST TO MOVE INTO THE NW CORNER
MON...EXTENDING FROM 29N65W TO CENTRAL FLORIDA TUE.

$$

.WARNINGS...ANY CHANGES IMPACTING COASTAL NWS OFFICES WILL BE
COORDINATED THROUGH AWIPS 12 PLANET CHAT OR BY TELEPHONE:

.GULF OF MEXICO...
GMZ011...NONE.
GMZ013...NONE.
GMZ015...NONE.
GMZ017...NONE.
GMZ019...NONE.
GMZ021...NONE.
GMZ023...NONE.
GMZ025...NONE.

.CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN
55W AND 64W...
AMZ011...NONE.
AMZ013...NONE.
AMZ015...NONE.
AMZ017...NONE.
AMZ019...NONE.
AMZ021...NONE.
AMZ023...NONE.
AMZ025...NONE.
AMZ027...NONE.
AMZ029...NONE.
AMZ031...NONE.
AMZ033...NONE.
AMZ035...NONE.
AMZ037...NONE.
AMZ039...NONE.

.SW N ATLANTIC INCLUDING THE BAHAMAS...
AMZ111...NONE.
AMZ113...NONE.
AMZ115...NONE.
AMZ117...NONE.
AMZ119...NONE.
AMZ121...NONE.
AMZ123...NONE.
AMZ125...NONE.
AMZ127...NONE.

*FOR DETAILED ZONE DESCRIPTIONS PLEASE VISIT:
HTTP://WWW.NHC.NOAA.GOV/ABOUTTAFBPROD.SHTML#OWF

NOTE: GRIDDED MARINE FORECASTS ARE AVAILABLE IN THE
NATIONAL DIGITAL FORECAST DATABASE (NDFD) AT:
HTTP://WWW.NHC.NOAA.GOV/MARINE/GRIDS.PHP

FOR ADDITIONAL INFORMATION PLEASE VISIT:
HTTP://WWW.HURRICANES.GOV/MARINE

$$
.FORECASTER LEWITSKY. NATIONAL HURRICANE CENTER.