000
AGXX40 KNHC 210807
MIMATS

MARINE WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
407 AM EDT SAT SEP 21 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 GFS. MEDIUM TO
LOW CONFIDENCE DUE TO DIFFERENCE IN MODEL HANDLING OF LOW PRES
AND COLD FRONT.

LOW PRES CENTER 1005 MB MOVING INLAND TONIGHT JUST S OF
BROWNVILLLE TEXAS WITH FRESH SOUTHERLY BREEZE AND 6-8 FT SEAS WITHIN
270 NM IN E QUADRANT. INTERACTION WITH APPROACHING COLD FRONT
LIKELY TO EXACERBATE ALREADY STRONG CONVECTION MAINLY IN E AND SE
QUADRANTS...BUT INTENSIFICATION INTO TROPICAL SYSTEM IS NOT
EXPECTED. LOW PRES CENTER APPEARS TO BECOME ELONGATED UNDER STRESS
FROM COLD FRONT AND STRONG UPPER LEVEL SW WINDS. MOST DYNAMIC
MODELS MAINTAIN CENTER ALIVE WHILE OTHERS...INCLUDING OFFICIAL
FORECAST...MERGE IT WITH COLD FRONT. THIS BEING THE REASON FOR
LOW CONFIDENCE. FRONT STALLS OVER CENTRAL GULF AND EVENTUALLY
BACKS N AS ATLC RIDGE EXTENDS INTO GULF ALONG 26N.

ELSEWHERE...STEADY MODERATE TO FRESH S-SE BREEZE WITH SEAS 4-6 FT BRING
ABUNDANT MOISTURE INTO COLD FRONT INTRUDING INTO NORTHERN GULF WITH
LINE OF CONVECTION ACROSS COASTAL WATER IN TEXAS THROUGH MISSISSIPPI.
S WINDS INCREASE IN VICINITY OF FRONTAL BOUNDARY AND SEAS BUILD TO
7-8 FT THROUGH TONIGHT.

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

MODEL PREFERENCE: OFFICIAL FORECAST BLENDED WITH LATEST GFS. 
HIGH CONFIDENCE.

LOW PRES 1005 MB NEAR 28N62W JUST E OF SW N ATLC FLATTENS PRES
GRADIENT ACROSS CARIBBEAN BASIN E OF 83W WITH LIGHT TO MODERATE
WINDS AND SEAS LESS THAN 4 FT. STEADY FRESH SE BREEZE WITH SEAS 5
TO 6 FT W OF 83W IN NW CARIBBEAN. CONDITIONS REMAIN SAT BUT
GRADIENT TIGHTENS AS LOW PRES IN SW N ATLC MOVES NE OUT OF REGION.
RIDGE THEN BUILDS BACK MON AND INCREASES WIND TO A FRESH TO
STRONG E BREEZE ACROSS CENTRAL CARIBBEAN WITH SEAS REACHING 9 FT
BY TUE. 

IN TROPICAL N ATLC...WEAK SURFACE TROUGH WITH EMBEDDED LOW PRES
1011 MB AT 14N55W BRINGS MODERATE TO FRESH NE TO ZONE TODAY THEN
WINDS TURN E-SE WITH SEAS 4-6 FT THROUGH WED AS TROUGH WEAKENS AND
MOVES W INTO EASTERN CARIBBEAN AND BECOMES ILL-DEFINED BY EARLY
MON.

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

MODEL PREFERENCE: OFFICIAL FORECAST BLENDED WITH GFS. MEDIUM
CONFIDENCE DUE TO DIFFERENCES IN LOW PRES MOVEMENT.

LOW PRES 1011 MB AT 28N62W HAS TROUGH EXTEND SW TO 24N67W TO NW
HISPANIOLA. SCATTERED MODERATE CONVECTION WITHIN 120 NM OF TROUGH
AXIS AND 240 NM E QUADRANT OF LOW PRES. FRESH TO STRONG WINDS
AROUND CENTER WITH SEAS TO 6-7 FT EXPECTED AND HIGHER IN VICINITY
OF ISOLATED STRONG CONVECTION. ELSEWHERE LIGHT TO MODERATE WINDS
OVER REMAINDER OF BASIN. 

AS LOW PRES CENTER AND TROUGH SHIFT E AND OUT OF AREA SAT...HIGH
PRES RIDGE BUILD ACROSS BASIN FROM CENTRAL ATLC THROUGH SUN. COLD 
FRONT FORECAST TO MOVE INTO NW CORNER OF BASIN MON...EXTENDING FROM
29N65W TO CENTRAL FLORIDA BY 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 WALLY BARNES. NATIONAL HURRICANE CENTER.