000 AGXX40 KNHC 040800 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 400 AM EDT MON MAY 4 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. MODEL PREFERENCE: 00 UTC GFS BLENDED WITH PREVIOUS/OFFICIAL FORECAST. 00 UTC TAFB NWPS FOR WAVE PARAMETERS. HIGH CONFIDENCE. CMAN OBSERVATIONS ALONG THE FLORIDA KEYS ARE INDICATING FRESH TO STRONG NE TO E WINDS THIS MORNING...IN AGREEMENT WITH A RECENT ASCAT SATELLITE PASS THAT SHOWS THE SIMILAR CONDITIONS ALONG THE NW COAST OF CUBA. THE ENHANCED FLOW IS BETWEEN BUILDING HIGH PRES OVER THE CAROLINA COAST AND A TROUGH OVER THE NW CARIBBEAN. ELSEWHERE MODERATE TO FRESH WINDS E TO SE WINDS ARE NOTED WITH SEAS SO FAR MAINLY 2 TO 4 FT...BUT WILL LIKELY BUILD SLIGHTLY ACROSS THE GULF THROUGH THE MORNING. JET ENERGY ALOFT DIGGING INTO THE BASE OF BROAD UPPER TROUGH EXTENDING FROM NE GULF TO THE WESTERN CARIBBEAN IS INTERACTING WITH THE OVERNIGHT CUBAN LAND BREEZE TO SUPPORT A FEW SHOWERS AND THUNDERSTORMS OVER THE STRAITS OF FLORIDA. THE FETCH AND DURATION OF THE E FLOW AGAINST THE FLORIDA CURRENT WILL RESULT IN SEAS BUILDING TO 8 FT OVER THE SE GULF OFF THE NW COAST OF CUBA TODAY. THE GRADIENT RELAXES TONIGHT AS THE HIGH SHIFTS EAST AND TROUGHING TO THE SOUTH DAMPENS OUT...AND A NEW TROUGH DEVELOPS OVER THE BAHAMAS. THIS WILL LEAVE GENERALLY MODERATE SE FLOW ACROSS MOST THE BASIN THROUGH FRI...EXCEPT WINDS MORE NE-E IN THE GULF E OF 87W...WITH SEAS SUBSIDING TO 3 TO 5 FT ACROSS THE SW HALF OF THE GULF AND 1 TO 3 FT IN THE NE HALF OF THE GULF FOR THE END OF THE WEEK. NE TO E WINDS WILL INCREASE TO 15 TO 20 KT ALONG AND JUST OFFSHORE OF THE NW PORTION OF THE YUCATAN PENINSULA DURING THE EVENING THROUGH EARLY MORNING HOURS EACH DAY THROUGH THE END OF THE WEEK. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... MODEL PREFERENCE: 00 UTC GFS BLENDED WITH PREVIOUS/OFFICIAL FORECAST. 00 UTC TAFB NWPS FOR WAVE PARAMETERS. HIGH CONFIDENCE. A BROAD UPPER TROUGH REACHES FROM THE NE GULF THROUGH THE NW CARIBBEAN INTO THE SW CARIBBEAN THIS MORNING. DIVERGENCE ALOFT ASSOCIATED WITH THE LEFT FRONT EXIT REGION OF A JET STREAK ON THE WEST SIDE OF THE TROUGH AND THE RIGHT REAR ENTRANCE REGION ON ANOTHER JET STREAK ON THE EAST SIDE OF THE TROUGH IS ENHANCING A SCATTERED THUNDERSTORMS BETWEEN GRAND CAYMAN AND CENTRAL CUBA EASTWARD TO THE WINDWARD PASSAGE THIS MORNING. THIS IS ALSO SUPPORTING A BROAD SURFACE TROUGH FROM WESTERN CUBA TO CENTRAL HONDURAS...THE REMNANT OF A DISSIPATED FRONTAL BOUNDARY. A 02 UTC ASCAT SATELLITE PASS INDICATED 20 TO 25 KT TRADE WINDS OVER THE S CENTRAL CARIBBEAN...WITH A CONCURRENT ALTIMETER SATELLITE PASS INDICATING SEAS TO 8 FT. THE FORECAST CONTINUES TO CALL FOR THIS AREA OF FRESH TO STRONG TRADES TO EXPAND ACROSS THE CENTRAL CARIBBEAN THROUGH TONIGHT AND PERSISTING THROUGH FRI WITH SEAS BUILDING TO 8 TO 11 FT AS THE SUBTROPICAL RIDGE BUILDS TO THE NORTHEAST. MODERATE TO FRESH TRADES WILL PERSIST OVER THE TROPICAL N ATLC WITH SEAS 5 TO 8 FT. ...SW N ATLANTIC INCLUDING THE BAHAMAS... MODEL PREFERENCE: 00 UTC ECMWF BLENDED WITH PREVIOUS/OFFICIAL FORECAST. 0 UTC ECWAVE GUIDANCE FOR SEAS. HIGH CONFIDENCE TODAY...THEN MEDIUM CONFIDENCE THEREAFTER MOST PARTICULARLY WITH THE POSSIBLE FORMATION OF LOW PRES IN VICINITY OF BAHAMAS. JET DYNAMICS ALOFT ASSOCIATED WITH AN UPPER TROUGH FROM THE NE GULF THROUGH THE NW CARIBBEAN IS ENHANCING A FEW SHOWERS FROM THE NORTH CENTRAL CUBAN COAST AS OBSERVED BY CUBAN WEATHER RADAR. A FEW THUNDERSTORMS ARE ALSO NOTED NEAR THE APPROACHES TO THE WINDWARD PASSAGE THIS MORNING. A STATIONARY FRONT REACHES FROM 25N65W TO THE SOUTHERN BAHAMAS. RECENT SHIP OBSERVATIONS AND A 02 UTC ASCAT SATELLITE PASS INDICATED 20 TO 25 KT NE WINDS ALONG THE TRAILING END OF THIS BOUNDARY ACROSS THE TCI AND TOWARD THE WINDWARD PASSAGE. BUOY OBSERVATIONS AND A RECENT ALTIMETER SATELLITE PASS INDICATE 8 TO 9 FT SEAS OVER MUCH OF THE AREA 65W AND 75W N OF 27N. THIS IS LINGERING NORTHERLY SWELL THAT WILL SUBSIDE TO 6 TO 7 FT THROUGH THIS MORNING. THE FORECAST ISSUE FOR TUE THROUGH FRI CONTINUES TO BE THE POSSIBLE DEVELOPMENT OF LOW PRES OVER THE NORTHERN BAHAMAS. SOME DISAGREEMENT PERSISTS IN MODEL OUTPUT REGARDING THE TIMING... POSITION AND STRENGTH OF THE LOW PRES. THE GFS APPEARS TO CONTINUE TO SUFFER FROM SOME CONVECTIVE FEEDBACK ISSUES WHICH IS LEADING TO A STRONGER SOLUTION...AND ALSO MUCH CLOSER TO THE SE UNITED STATES COAST COMPARED TO THE LATEST ECMWF AND UKMET SOLUTIONS. THE NEW 00 UTC ECMWF IS A GOOD COMPROMISE BETWEEN THE GFS AND MORE EASTWARD UKMET SOLUTION AND IS LINE WITH CONSISTENT OUTPUT FROM THE EC ENSEMBLE SHOWING A RELATIVELY WEAKER LOW PRES AREA FORMING FROM A TROUGH IN THE NORTHERN BAHAMAS BY WED AND SHIFTING NNW. THE ECMWF ALSO INDICATES SOME STRENGTHEN WED INTO THU AS THE LOW DRIFTS N OF THE AREA...BUT STILL WELL BELOW THE MORE AGGRESSIVE GFS AND CANADIAN SOLUTIONS. NEEDLESS TO SAY MUCH UNCERTAINTY REMAINS WITH THIS LOW AND THE FORECAST WILL CONTINUE TO FOLLOW THE MORE CONSERVATIVE ECMWF SOLUTION. ELSEWHERE MODERATE SE FLOW PERSIST ACROSS THE REGION IN THE WAKE OF THE TROUGH/LOW. $$ .WARNINGS...ANY CHANGES IMPACTING COASTAL NWS OFFICES WILL BE COORDINATED THROUGH AWIPS 12 PLANET CHAT OR BY TELEPHONE: .GULF OF MEXICO... NONE. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... NONE. .SW N ATLANTIC INCLUDING THE BAHAMAS... NONE. $$ *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 CHRISTENSEN. NATIONAL HURRICANE CENTER.