654  
AGXX40 KNHC 230735  
MIMATS  
 
MARINE WEATHER DISCUSSION  
NWS NATIONAL HURRICANE CENTER MIAMI FL  
235 AM EST THU NOV 23 2017  
 
MARINE WEATHER DISCUSSION FOR THE GULF OF MEXICO, CARIBBEAN SEA,  
AND TROPICAL NORTH ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W  
AND THE SOUTHWEST NORTH ATLANTIC INCLUDING THE BAHAMAS  
   
..GULF OF MEXICO
 
 
AS OF 0600 UTC, A 1012 MB LOW PRESSURE SYSTEM IS LOCATED NEAR  
28N86W. A STATIONARY FRONT EXTENDS FROM THE LOW ACROSS NORTHERN  
FLORIDA INTO THE SW N ATLANTIC. A COLD FRONT ALSO STRETCHES FROM  
THE LOW SW ACROSS THE EASTERN BAY OF CAMPECHE. A VIGOROUS SHORT-  
WAVE TROUGH ROTATING THROUGH A VERY WELL PRONOUNCED LONGWAVE  
TROUGH THAT ENTERS THE GULF ACROSS SE LOUISIANA, AND EXTENDS TO  
NEAR TUXPAN, MEXICO SUPPORTS THESE FEATURES. HIGH PRESSURE IS  
BUILDING SOUTHWARD OVER THE WESTERN GULF BEHIND THE FRONT COLD  
FRONT WITH A 1027 MB CENTER NEAR TMPICO, MEXICO. A VERY TIGHT  
PRESSURE GRADIENT BETWEEN THE HIGH PRESSURE AND THE COLD FRONT  
HAS RESULTED IN A LARGE SWATH OF STRONG TO GALE FORCE NORTHERLY  
WINDS OVERTAKING THE WATERS TO THE W OF THE COLD FRONT. THE MOST  
RECENT SCATTEROMETER DATA CONFIRMED THE PRESENCE OF THESE WINDS.  
IN ADDITION, AN ALTIMETER PASS INDICATED SEAS OF NEAR 15 FT OVER  
THE WESTERN BAY OF CAMPECHE. DOPPLER RADAR SHOWS SCATTERED  
SHOWERS AND THUNDERSTORMS OVER THE NE GULF WATERS IN ASSOCIATION  
WITH THE LOW WHILE SIMILAR CONVECTIVE ACTIVITY IS NOW APPROACHING  
SW FLORIDA AND THE FLORIDA KEYS. WINDS AND SEAS COULD BE HIGHER  
NEAR TSTMS. THE LOW PRESSURE WILL MOVE ACROSS NORTHERN FLORIDA  
TODAY REACHING THE SW N ATLANTIC BY THIS EVENING DRAGGING THE  
ASSOCIATED COLD FRONT, FORECAST TO CROSS THE YUCATAN CHANNEL BY  
EARLY FRI MORNING. MINIMAL GALE FORCE WINDS ARE EXPECTED TO  
PERSIST OVER THE SW GULF THROUGH EARLY THIS MORNING, THEN WINDS  
AND SEAS WILL BEGIN TO GRADUALLY DIMISNISH ACROSS THE GULF REGION  
AS THE FRONT EXITS THE AREA. HIGH PRESSURE IN THE WAKE OF THE  
FRONT WILL DOMINATE THE GULF ON FRI WITH GENTLE TO MODERATE  
NORTHERLY WINDS AND SEAS OF 3 TO 5 FT. SOUTHERLY RETURN FLOW WILL  
BRIEFLY SET-UP OVER THE WESTERN GULF ON SAT, THEN A RIDGE WILL  
BUILD AGAIN ACROSS THE GULF WATERS ON SUN, PRODUCING MAINLY  
GENTLE TO MODERATE NORTHERLY WINDS AND SEAS OF 2 TO 3 FT.  
 
...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN  
55W AND 64W...  
 
A PERSISTENT SURFACE TROUGH IS ANALYZED ALONG 81W FROM 11N TO  
22N. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE SEEN NEAR  
THIS FEATURE. THE TROUGH IS FORECAST TO DRIFT EASTWARD OVER THE  
NEXT COUPLE OF DAYS AS A COLD FRONT REACHES THE NW CARIBBEAN.  
GENTLE TO MODERATE TRADES AND SEAS OF 4 TO 5 FT ARE NOTED E OF  
THE TROUGH AXIS OVER THE EAST AND CENTRAL CARIBBEAN WHILE MAINLY  
GENTLE NORTHERLY WINDS AND SEAS OF 2 TO 3 FT PREVAIL WEST OF THE  
TROUGH AXIS OVER THE WESTERN CARIBBEAN. THE COLD FRONT, CURRENTLY  
MOVING ACROSS THE GULF OF MEXICO, IS FORECAST TO ENTER THE NW  
CARIBBEAN BY EARLY FRI MORNING, REACHING FROM WESTERN CUBA TO  
BELIZE BY FRI EVENING, AND FROM CENTRAL CUBA TO THE GULF OF  
HONDURAS ON SAT EVENING WHILE DISSIPATING. THE PRESSURE GRADIENT  
BETWEEN BUILDING HIGH PRESSURE OVER CENTRAL AMERICA AND THE  
FRONTAL BOUNDARY SHOULD BRING AN INCREASE IN NORTHERLY WINDS OF  
MOSTLY 20 KT WITH POSSIBLE POCKETS OF 25 KT WITHIN ABOUT 120 NM  
OFF THE NICARAGUA COAST TONIGHT THROUGH MONDAY NIGHT ALONG WITH  
MAX COMBINED SEAS OF 6 OR 7 FT. THERE IS A POSSIBILITY THAT SEAS  
MAY REACH 8 FT ON MONDAY AS SUGGEST BY LATEST MARINE GUIDANCE.  
   
..SW N ATLANTIC INCLUDING THE BAHAMAS
 
 
A RIDGE IS NOW CONFINED TO THE EXTREME SE WATERS. A 1008 MB LOW  
PRESSURE IS OVER THE NE WATERS NEAR 30N67W WITH A COLD FRONT  
EXTENDING SOUTHWESTWARD TO THE SE BAHAMAS. LATEST SATELLITE  
IMAGERY SHOWS A LARGE AREA OF SHOWERS, WITH EMBEDDED TSTMS ON  
THE SE SEMICIRCLE OF THE LOW CENTER. THE MOST RECENT ASCAT PASS  
PROVIDED OBSERVATIONS OF MINIMAL GALE FORCE WINDS WITHIN ABOUT  
150 NM ON THE SE QUADRANT OF THE LOW, WITH A SWATH OF FRESH TO  
STRONG SOUTHERLY WINDS COVERING THE WATERS N OF 23N BETWEEN 63W  
AND 67W. AN ALTIMETER PASS INDICATED SEAS UP TO 14 FT WITHIN THE  
AREA OF GALE FORCE WINDS. THESE CONDITIONS WILL EXIT FORECAST  
ZONE AMZ115 LATE THIS MORNING AS THE LOW PRESSURE MOVES NORTH OF  
AREA.  
 
ANOTHER LOW PRESSURE SYSTEM, CURRENTLY OVER THE EASTERN GULF OF  
MEXICO, WILL MOVE ACROSS NORTHERN FLORIDA TODAY REACHING THE SW  
N ATLANTIC BY THIS EVENING. THE ASSOCIATED COLD FRONT WILL MOVE  
ACROSS THE WESTERN AND CENTRAL WATERS TROUGH EARLY SUNDAY MORNING,  
AND ACROSS THE EASTERN AND SE WATERS LATE SUNDAY THROUGH MONDAY  
AS IT WEAKENS TO A FRONTAL TROUGH. SCATTERED SHOWERS AND  
THUNDERSTORMS WITH POSSIBLE GUSTY WINDS ARE EXPECTED WITH BOTH  
THE LOW AND THE COLD FRONT. MODEL GUIDANCE SUGGESTS THAT A  
REINFORCING COLD FRONT WILL REACH THE NORTH WATERS BY SUN EVENING  
AND MOVE SOUTHWARD THROUGH MON NIGHT, THAN STALL NEAR 27N ON TUE.  
 

 
   
WARNINGS
 
ANY CHANGES IMPACTING COASTAL NWS OFFICES WILL BE  
COORDINATED THROUGH AWIPS II COLLABORATION CHAT, OR BY  
TELEPHONE:  
   
GULF OF MEXICO
 
   
GMZ023...SW GULF S OF 22N W OF 94W
 
 
GALE WARNING EARLY TODAY.  
 
.CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN  
55W AND 64W...  
NONE.  
   
SW N ATLANTIC INCLUDING THE BAHAMAS
 
   
AMZ115...ATLANTIC FROM 27N TO 31N BETWEEN 65W AND 70W
 
 
GALE WARNING EARLY TODAY.  
 

 
 
*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.NHC.NOAA.GOV/MARINE  
 

 
 
.FORECASTER GR. NATIONAL HURRICANE CENTER.  
 
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