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AGXX40 KNHC 181111 RRA
MIMATS

MARINE WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
258 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 ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W...

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.

THE 06Z SYNOPTIC ANALYSIS INDICATES A RIDGE...SLIGHTLY WEAKER THAN PREVIOUS DAYS...EXTENDING SEWD FROM THE SW GULF OF MEXICO TO NORTHERN NICARAGUA. AN ASCAT PASS FROM 0258 UTC LAST NIGHT AGAIN REVEALED A SWATH OF NE 20-25 KT SW OF CUBA TO 18N BETWEEN 78W-81W. THE EDGE OF THE SAME SWATH SUGGESTED SIMILAR WINDS TO EXIST ALONG AND WITHIN 120 NM OF THE COAST OF COLOMBIA. MODEL GUIDANCE ALONG WITH SURFACE ANALYSIS EXTRAPOLATION INDICATES THAT THESE WINDS WILL CONTINUE THROUGH THE 24 HOURS SW OF CUBA AND THROUGH THE FORECAST PERIOD NEAR THE COAST OF COLOMBIA...BUT IN A PULSING FASHION DURING THE NIGHT TIME AND EARLY MORNING HOURS WITH SEAS THERE BUILDING TO 8 FT.

ELSEWHERE ACROSS THE CARIBBEAN...BUOY AND ASCAT DATA ARE SHOWING MAINLY GENTLE TO MODERATE NE-E WINDS THROUGHOUT EXCEPT FOR GENTLE E-SE WINDS ACROSS THE FAR NORTHERN TROPICAL N ATLC WHERE A WEAKENING COLD FRONT EXTENDS FROM 19N55W SW TO GUADELOUPE AND W AS A DISSIPATING COLD FRON15N74W. SEAS ELSEWHERE IN THE CARIBBEAN ARE IN THE 3-5 FT RANGE...EXCEPT FOR LOWER SEAS OF 2-3 FT IN THE FAR EASTERN CARIBBEAN AND 5-7 FT SEAS IN THE SW CARIBBEAN NEAR THE COAST OF COLOMBIA. RECENT ALTIMETER DATA VERIFIED WELL WITH THE MWW3 GUIDANCE VALUES. SEAS IN THE TROPICAL N ATLC ARE IN THE 5-6 FT RANGE IN A NE TO E SWELL COMPONENT PER CURRENT BUOY DATA AND RECENT ALTIMETER DATA. THESE SEAS WILL REMAIN IN THAT SIMILAR RANGE DURING THE PERIOD.


...SW N ATLANTIC S OF 31N W OF 55W INCLUDING THE BAHAMAS...

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.

06Z PRELIMINARY SYNOPTIC ANALYSIS SHOWS A 1020 MB HIGH CENTERED E OF THE DISCUSSION AREA NEAR 30N54W EXTENDING A RIDGE AXIS W-SW TO 27N65W TO THE SOUTHERN FLORIDA PENINSULA NEAR 25N80W. TO THE NORTH OF THIS RIDGE AXIS...A RATHER FAST MOVING COLD FRONT NOW EXTENDS FROM 31N68W TO WEST PALM BEACH. AN ASCAT PASS FROM 0120 UTC LAST NIGHT INDICATED GENERALLY W-NW 15-20 KT N OF 30N W OF THE FRONT TO ABOUT 71W...WITH GENTLE NW WINDS ELSEWHERE N OF THE FRONT. BUOYS AND A FEW SHIP OBS SHOW SEAS IN THE RANGE OF 4-5 FT E OF THE BAHAMAS...EXCEPT FOR 5-7 FT SEAS IN NW SWELLS N OF 30N BETWEEN THE FRONT AND 71W. LOWER SEAS OF 1-2 FT ARE PRESENT SW OF THE BAHAMAS.

THE COLD FRONT WILL WEAKEN AS IT REACHES FROM NEAR 28N65W TO 26N72W...AND DISSIPATING STATIONARY TO THE NW BAHAMAS TONIGHT...THEN CONTINUE TO WEAKEN AS MOVES ACROSS THE SE PORTION FRI THROUGH SAT. HIGH PRES WILL ONCE AGAIN BUILD ACROSS THE BASIN IN THE WAKE OF THE THROUGH SAT NIGHT...BUT SHIFT EASTWARD THROUGH SUN IN RESPONSE TO ANOTHER COLD FRONT THAT APPROACHES THE FAR NW CORNER OF THE AREA EARLY ON SUN ASSOCIATED WITH LOW PRES MOVING NEWD OFF THE SE U.S. COAST. RIGHT NOW GUIDANCE SUGGESTS THAT THE UPPER FLOW WILL NOT BE ADEQUATE ENOUGH TO ALLOW THIS NEXT COLD FRONT TO ADVANCE MUCH TOWARDS THE FORECAST WATERS AS IT MOST LIKELY WILL BECOME STATIOANRY JUST NW OF THE BASIN.

$$


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


.GULF OF MEXICO... NONE.


.CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... NONE.


.SW N ATLANTIC INCLUDING THE BAHAMAS... 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.HURRICANE WARNINGS.GOV/MARINE

$$
.FORECASTER AGUIRRE. NATIONAL HURRICANE CENTER.

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