000
AGXX40 KNHC 180757
MIMATS

MARINE WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
252 AM EST THU DEC 18 2014

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: 00Z GFS BLENDED WITH PREVIOUS OFFICIAL 
FORECAST. FOR WAVEHEIGHTS USED BLEND OF 00Z MWW3 WITH PREVIOUS 
OFFICIAL AND NWPS WAVE PARAMETERS. HIGH CONFIDENCE...EXCEPT 
MEDIUM CONFIDENCE DAYS 4 AND 5 WITH FRONTAL POSITION. 

06Z PRELIMINARY SYNOPTIC ANALYSIS SHOWS A WEAKENING STATIONARY 
FRONT EXTENDING FROM FORT MYERS SW TO 25N90W...THEN BECOMES A 
WARM FRONT NW TO INLAND TEXAS JUST N OF GALVESTON...AND SW TO 
WEAK LOW PRES OF 1014 MB OVER S TEXAS. HIGH PRES IS BRIDGING 
EASTWARD ACROSS THE FRONT. LATEST OBSERVATIONS AND SCATTEROMETER 
PASSES FROM 0300 UTC LAST NIGHT SHOW GENTLE NE-E WIND FLOW N OF 
THE FRONT E OF 90W. GENTLE E WINDS ARE S OF THE FRONT E OF 
90W...AND MOSTLY SE-S WINDS ARE OVER THE WESTERN GULF S OF THE 
WARM FRONT. THE OBSERVATIONS SHOW SEAS IN THE 1-2 FT RANGE WITH 
SEAS NOW HAVING BUILT TO 4-5 FT OVER THE WESTERN GULF UNDER THE 
MODERATE SE-S FLOW.
 
MODELS IN AGREEMENT THAT THE WARM FRONT WILL LIFT N ACROSS 
SOUTHERN CENTRAL AND NE TEXAS AND THE ADJACENT COASTAL WATERS 
THROUGH FRI AS JET STREAM ENERGY AHEAD OF AN UPPER LEVEL TROUGH 
PERSIST OVER EASTERN TEXAS. WITH AMPLE SLY MOIST FLOW COMING IN 
FROM THE WESTERN GULF AND WITH THE ENERGY ALOFT IN PLACE...THE 
LOW PRES WILL BE REINFORCED OR REFORM AS TRACKS NE-E ALONG THE 
COASTAL PLAINS FROM NE TEXAS TO NEAR THE MOUTH OF THE 
MISSISSIPPI RIVER BY SAT. MODELS CONTINUE TO BE IN GOOD IN 
AGREEMENT WITH TRACK OF THE LOW AND WITH THE FORECAST POSITIONS 
OF THE ASSOCIATED COLD FRONT. THE COLD FRONT IS FORECAST TO MOVE 
ACROSS THE FAR WESTERN PORTION OF THE GULF BEGINNING FRI 
EVENING. BY SAT AS THE LOW APPROACHES NEAR THE MOUTH OF THE 
MISSISSIPPI RIVER...THE FRONT WILL EXTEND FROM IT SW TO NEAR 
TAMPICO...FROM NEAR APALACHICOLA SW TO THE EASTERN BAY OF 
CAMPECHE BY EARLY SAT NIGHT...THEN BEGIN TO WEAKEN AS IT REACHES 
FROM APALACHEE BAY TO NEAR 26N89W WHERE IT BECOMES A DISSIPATING 
STATIONARY FRONT TO THE EASTERN BAY OF CAMPECHE SUN...AND TO A 
POSITION SLIGHTLY E FROM THERE ON MON. FORECAST CONFIDENCE WILL 
BE MEDIUM LATE SUN INTO MON WITH RESPECT TO THE FRONTAL BOUNDARY 
IDENTITY...WHETHER ALL OF IT BECOMES STATIONARY AT THAT POINT OR 
JUST THE NE PART REMAINS COLD. BASED ON UPPER LEVEL MODEL FLOW 
GUIDANCE...IT APPEARS BY LATE SUN AND INTO MON THE UPPER FLOW 
WILL BE MAINLY SWLY. THAT ALONG WITH THE THERMAL GRADIENT BEING 
ABOUT THE SAME ON EITHER SIDE OF IT...THE FRONT WILL MOST LIKELY 
BE STALLED ALONG THE SAME POSITION AS THE ONE FROM MON. 

WITH RESPECT TO WINDS BEHIND THE FRONT...MODELS ARE IN GENERAL 
AGREEMENT WITH A BRIEF ONSET OF NLY 15-20 KT BEHIND THE FRONT 
OVER THE FAR WESTERN WATERS BORDERING THE COASTAL OFFSHORE 
WATERS FRI NIGHT AS THE PRES GRADIENT BETWEEN HIGH PRES BUILDING 
EASTWARD BEHIND THE FRONT AND AFOREMENTIONED LOW PRES IS 
CONDUCIVE FOR INITIATING SUCH WINDS. THESE WINDS THEN QUICKLY 
WEAKEN TO 10-15 KT EARLY SAT AFTERNOON AS THEY BEGIN TO SHIFT TO 
THE NE IN DIRECTION...AND WEAKEN SLIGHTLY TO 10 KT LATE SAT 
NIGHT INTO SUN. BY LATE SUN NIGHT WINDS OVER THE WESTERN GULF 
BECOME SE AT MODERATE SPEEDS AND MORE SLY BY EARLY MON. GFS IS 
THE ONLY MODEL THAT DEVIATES FROM SHOWING THESE WINDS DIRECTIONS 
LATE SUN NIGHT AND MON AS IT SHOWS N-NE WINDS INSTEAD. SEAS IN 
THE WESTERN GULF BEHIND THE FRONT ARE EXPECTED TO BE IN THE 4-6 
FT RANGE FRI NIGHT INTO SAT...WITH SOME POCKETS OF 6-7 FT SEAS 
OR BRIEF INSTANCE OF SEAS TO 8 FT MAINLY IN THE COASTAL WATERS 
OF CENTRAL TEXAS. SEAS SUBSIDE QUICKLY TO 3-5 FT SAT NIGHT AND 
TO 2-3 FT SUN. 

...CARIBBEAN SEA AND TROPICAL N