000 AGXX40 KNHC 200453 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1253 AM EDT MON APR 20 2015 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: LATEST GFS BLENDED WITH PREVIOUS OFFICIAL. TAFB NWPS BLENDED INTO PREVIOUS OFFICIAL FOR WAVE PARAMETERS. HIGH CONFIDENCE. THE CONVECTIVE ACTIVITY HAS SHIFTED E TO OVER THE FAR E-CENTRAL GULF AND SHOULD SHIFT E OF THE AREA TODAY. RIGGS REPORTING LOCAL VSBY 3-5 SM IN FOG TO THE N OF 27N W OF 93W...THUS INTRODUCED INTO WEATHER GRIDS FOR FIRST PERIOD. A COLD FRONT CURRENTLY OVER THE TX COASTAL WATERS WILL CONTINUE E ACROSS THE N-CENTRAL WATERS TODAY...AND THROUGH THE NE GULF WATERS TONIGHT. THE ECMWF MOVES THE FRONT SLIGHTLY FASTER EARLY TODAY THAN THE GFS...BUT BOTH MODELS LINE UP FAIRLY CLOSE AFTER 18 HOURS. STILL EXPECT POST-FRONTAL NE-E 15-20 KT FLOW IN THE WAKE OF THE FRONT ACROSS THE NW GULF THIS AFTERNOON INTO EARLY TONIGHT...DIMINISHING TO NE-E 10-15 KT WINDS BY MIDNIGHT TONIGHT. OTHERWISE EXPECT SW 10- 15 KT AHEAD OF THE FRONT TO QUICKLY CLOCK TO NE-E AT 10-15 KT IN THE WAKE OF THE FRONT AND SPREAD E ACROSS THE ENTIRE NORTHERN GULF BY MID-MORNING ON TUE. EXPECT THE LOCALIZED EVENING THERMAL ENHANCEMENT ALONG THE NW COAST OF THE YUCATAN PENINSULA TO BE IN THE 15-20 KT RANGE EACH EVENING THROUGH WED THU EVENING...THEN GUIDANCE SUGGESTS A 20-25 KT EVENT ON FRI EVENING. THESE E-SE PULSES WILL PROPAGATE W ACROSS THE E BAY OF CAMPECHE DURING THE MORNING DAYLIGHT HOURS...WITH THE TROUGH LOSING IDENTITY OVER THE CENTRAL BAY OF CAMPECHE BY THE EARLY AFTERNOONS. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... MODEL PREFERENCE: LATEST GFS BLENDED WITH PREVIOUS OFFICIAL. TAFB NWPS BLENDED INTO PREVIOUS OFFICIAL FOR WAVE PARAMETERS WITH MANUAL ADJUSTMENTS. MEDIUM-HIGH CONFIDENCE. ATLC RIDGING N OF THE AREA...COMBINED WITH LOW PRES OVER NW COLOMBIA...WILL SUPPORT 20-25 KT NE WINDS WITHIN 180 NM OF THE NW COAST OF COLOMBIA TONIGHT...THEN THE AFFECTED AREA SHOULD SHRINK TO WITHIN 150 NM OF THE COLOMBIAN COAST EACH NIGHT THROUGH FRI NIGHT. E-SE TRADES WILL INCREASE TO 20-25 KT ACROSS THE GULF OF HONDURAS EACH NIGHT WITH SEAS BUILDING TO 9 FT. MODERATE TO FRESH TRADES EXPECTED ELSEWHERE. N SWELL RESULTING IN 7-9 FT COMBINED SEAS EXTEND W ACROSS THE TROPICAL ATLC WATERS TO THE EASTERN CARIBBEAN PASSAGES. THESE CONDITIONS WILL SUBSIDE FROM THE N TODAY AND TONIGHT WITH SEAS LESS THAN 8 FT ACROSS THE TROPICAL WATERS BY NOON TUE. THE NEXT ROUND OF NNE SWELL WILL REACH 19N55W ON WED NIGHT DRIVING THE COMBINED SEAS UP TO 8 FT AGAIN BY MIDDAY THU...WITH THESE CONDITIONS REACHING THE E CARIBBEAN PASSAGES THU EVENING AND CONTINUING THROUGH EARLY FRI...THEN SUBSIDING FROM THE N ON FRI NIGHT AND SAT. ...SW N ATLANTIC INCLUDING THE BAHAMAS... MODEL PREFERENCE: LATEST GFS BLENDED WITH PREVIOUS OFFICIAL WHICH WAS A PRIMARILY ECMWF. TAFB NWPS BLENDED WITH PREVIOUS OFFICIAL FOR WAVE PARAMETERS WITH MANUAL ADJUSTMENTS TO MATCH OBS. MEDIUM-HIGH CONFIDENCE. A COLD FRONT EXTENDS FROM 31N53W TO 27N65W WHERE IT BECOMES A VERY WEAK WARM FRONT EXTENDING NW TO BEYOND 31N70W. THE COLD FRONT SEGMENT WILL CONTINUE SE TODAY...ACCOMPANIED BY ONLY A 10- 15 KT WIND SHIFT...STALLING E-W BRIEFLY TONIGHT FROM 26N55W TO 31N68W...THEN QUICKLY LIFTING NE AS A WEAK WARM FRONT ON TUE... AND GRADUALLY WASHING OUT THROUGH EARLY WED. SOUTHERLY FLOW WILL INCREASE TO 15-20 KT OVER THE FAR NW WATERS THIS MORNING...WITH THESE CONDITIONS SPREADING E ACROSS THE AREA N OF 28N W OF 73W BY THIS EVENING...AHEAD OF A SECOND COLD FRONT MOVING E OFF THE SE GA/NE FL COASTS LATE TONIGHT. THIS SECOND WEAK COLD FRONT WILL REACH FROM 31N70W TO THE NW BAHAMAS LATE TUE NIGHT...THEN STALL FROM 28N55W TO THE BAHAMAS AT 26N...THEN QUICKLY LOSE IDENTITY. ANOTHER ROUND OF N SWELLS WILL ARRIVE ACROSS THE WATERS N OF 29N E OF 60W TONIGHT...GRADUALLY BUILDING SEAS TO 7- 10 FT ACROSS THE DISCUSSION WATERS BETWEEN 65-55W BY LATE TUE. THIS SECOND ROUND OF N SWELLS WILL THEN GRADUALLY SUBSIDE TO BELOW 8 FT BY THU AFTERNOON. ANOTHER COLD FRONT WILL MOVE INTO THE NW WATERS LATE THU...AND REACH FROM BERMUDA TO THE CENTRAL BAHAMAS LATE FRI ACCOMPANIED BY A 10-15 KT SW-W-NW WIND SHIFT. $$ .WARNINGS...ANY CHANGES IMPACTING COASTAL NWS OFFICES WILL BE COORDINATED THROUGH AWIPS 12 PLANET CHAT OR BY TELEPHONE: .GULF OF MEXICO... NONE. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... NONE. .SW N ATLANTIC INCLUDING THE BAHAMAS... NONE. $$ *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 NELSON. NATIONAL HURRICANE CENTER.