000
AGXX40 KNHC 071820
MIMATS

MARINE WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
120 PM EST SAT DEC 7 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: SMALL PERCENTAGE OF LATEST GFS BLENDED INTO 
PREVIOUS GLOBAL MODEL CONSENSUS WITH GOOD CONFIDENCE. SMALL 
PERCENTAGE OF LATEST MWW3 BLENDED INTO PREVIOUS WAVE PARAMETERS. 
 
A COLD FRONT EXTENDING FROM 30N85W TO 23N93W TO 18N94W WILL 
BEGIN TO LOSE MOMENTUM TONIGHT AND STALL FROM 30N85W TO 25N91W 
TO 18N93W ON SUN...THEN BEGIN TO MOVE WESTWARD ON SUN NIGHT WITH 
A FRONTAL WAVE...OR POSSIBLE WEAK SURFACE LOW...BRIEFLY FORMING 
ALONG THE FRONTAL BOUNDARY NEAR 26N95W AS EARLY AS SUNRISE ON 
SUN. A STRENGTHENING ATLC RIDGE WILL PUSH THE FRONT W-NW AS A 
WEAK WARM FRONT ON SUN NIGHT WITH THE FRONTAL REMNANTS QUASI-
STATIONARY STATIONARY ACROSS THE FAR NW GULF WATERS ON MON 
MORNING. A SECOND COLD FRONT WILL MOVE INTO THE NW GULF BY MON 
AFTERNOON...ABSORBING THE INITIAL FRONT'S REMNANTS...WITH THE 
MERGED BOUNDARY EXTENDING FROM THE FL BIG BEND TO THE CENTRAL 
BAY OF CAMPECHE ON TUE. THE PATTERN THEN REPEATS WITH THIS 
SECOND FRONT STALLING FROM W-CENTRAL FL TO A FRONTAL WAVE NEAR 
25N95W ON WED AND THU.

THE NORTHERLY FLOW W OF THE FRONT WILL QUICKLY DIMINISH FROM 20-
25 KT EARLY THIS AFTERNOON TO 15-20 KT LATE TONIGHT. EXPECT ONLY 
NE 10-15 KT WINDS W AND N OF THE FRONT BY SUN AFTERNOON AS E-SE 
10-15 KT RETURN FLOW SETS UP EVERYWHERE E AND SE OF THE FRONT. 
LITTLE CHANGE EXPECTED ON MON MORNING...THEN THE NE FLOW WILL 
INCREASE TO 20-25 KT W OF THE MERGING FRONTS ON MON 
AFTERNOON...WITH THESE CONDITIONS THEN SPREADING SE BEHIND THE 
FRONT THROUGH TUE. THE GRADIENT WILL RELAX WITH N-NE WINDS 
DIMINISHING TO 15-20 KT BY LATE WED. GUIDANCE INCREASES THE 
GRADIENT AGAIN ON THU SUPPORTING N-NE 20-25 KT ACROSS THE N AND 
W CENTRAL WATERS AND NE 15-20 KT ELSEWHERE. 

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

MODEL PREFERENCE: SMALL PERCENTAGE OF LATEST GFS BLENDED INTO 
PREVIOUS PACKAGE WITH GOOD CONFIDENCE. SMALL PERCENTAGE OF 
LATEST MWW3 BLENDED INTO PREVIOUS WAVE PARAMETERS.

A SURFACE FRONTAL TROUGH/SHEAR LINE EXTENDS ACROSS THE AREA
ALONG 18-19N TO THE E OF PUERTO RICO. AN UPPER CYCLONE IS 
CENTERED OVER THE LEEWARDS...AND CONTINUES TO ENHANCE PRECIP 
ALONG THE DECAYING FRONT. AS THE ATLC RIDGE N OF THE AREA 
STRENGTHENS...IT WILL PUSH THE DECAYING FRONT FURTHER SOUTHWARD 
AND INCREASE THE NE-E TRADES TO AT LEAST 20-25 KT ACROSS THE 
AREA MAINLY E OF 85W...WITH E 25-30 KT EXPECTED ACROSS THE N-
CENTRAL CARIBBEAN. THE ATLC RIDGE WILL SHIFT E AND WEAKEN EARLY 
NEXT WEEK WITH THE GRADIENT GRADUALLY RELAXING THROUGH THE 
MIDDLE OF THE WEEK. EXPECT MAX SEAS HEIGHTS OF 12 FT ACROSS N-
CENTRAL CARIBBEAN WATERS...AND A MAX OF 10 FT IN LONG PERIOD NE 
SWELL IN THE ATLC PASSAGES. 
 
...SW N ATLANTIC W OF 55W INCLUDING THE BAHAMAS...

MODEL PREFERENCE: SMALL PERCENTAGE OF LATEST GFS BLENDED INTO 
PREVIOUS PACKAGE GLOBAL MODEL CONSENSUS. SMALL PERCENTAGE OF 
LATEST MWW3 BLENDED INTO PREVIOUS WAVE PARAMETERS. INFO 
ONLY...HEAVY PERCENTAGE OF UKMET FOR ATLC E OF 55W THROUGH FIRST 
48 HRS. 

SURFACE HIGH PRESSURE CENTERED JUST SE OF BERMUDA HAS A RIDGE 
EXTENDING W-SW TO CENTRAL FL. THE EASTERLY TRADES S OF 25N WILL
CONTINUE AT 20-25 KT...AND SPREAD W THROUGH THE BAHAMAS THROUGH
EARLY TUE ACCOMPANIED BY SEAS OF 8-12 FT IN LONG PERIOD N-NE
SWELL. THE RIDGE WILL WEAKEN AND SHIFT E DURING THE MIDDLE OF
THE WEEK ALLOWING A WEAK COLD FRONT TO MOVE INTO THE NW ATLC
WATERS LATE TUE. THE FRONT WILL STALL FROM BERMUDA TO CENTRAL
FL LATE WED THEN DRIFT NW WITH GUIDANCE HINTING AT FRONTAL
WAVE DEVELOPMENT NEAR 31N77W ON THU.  

$$

.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...GALE WARNING ENDING EARLY THIS AFTERNOON.
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 NELSON. NATIONAL HURRICANE CENTER.