000 AGXX40 KNHC 030757 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 357 AM EDT SUN MAY 3 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 VALUES FOR WAVE PARAMETERS. HIGH CONFIDENCE. HIGH PRES PREVAILS ACROSS THE NORTHERN GULF...WITH LIGHT TO GENTLE BREEZES WITH 2 TO 3 FT ARE NOTED BY BUOY OBSERVATIONS AND SCATTEROMETER SATELLITE DATA. A FEW SHOWERS AND THUNDERSTORMS ALONG A SURFACE TROUGH OFF THE SW COAST OF FLORIDA. ELSEWHERE DRY AIR ALOFT ASSOCIATED WITH A BROAD UPPER TROUGH EXTENDING FROM THE NE GULF TO THE NW CARIBBEAN IS MAINTAINING GENERALLY BENIGN WEATHER. THE PATTERN BECOMES MORE AMPLIFIED OVER THE NEXT SEVERAL DAYS AS AN UPPER IMPULSE MOVES FROM THE SOUTHERN PLAINS INTO BASE OF THE UPPER TROUGH. GLOBAL MODELS INDICATE TROPICAL MOISTURE SHIFTING NORTHWARD AHEAD OF THIS IMPULSE INTO THE SE GULF...ALLOWING FOR INCREASE SHOWERS AND THUNDERSTORMS OVER THE SE GULF BY MON NIGHT INTO TUE. THE AMPLIFYING PATTERN WILL ALSO ALLOW THE SUBTROPICAL RIDGE OFF THE CAROLINA COAST TO BUILD. THE RESULTING INCREASED GRADIENT ALONG WITH TROUGHING OVER THE NW CARIBBEAN AND SE GULF WILL ALLOW FRESH TO OCCASIONAL STRONG EASTERLY FLOW OVER THE STRAITS OF FLORIDA TONIGHT INTO MONDAY. 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 ON MONDAY. THE GRADIENT RELAXES BY TUE AS THE HIGH SHIFTS EAST AND TROUGHING TO THE SOUTH DAMPENS OUT...LEAVING GENERALLY MODERATE SE FLOW ACROSS MOST THE BASIN THROUGH THU WITH SEAS SUBSIDING TO 3-5 FT ACROSS THE SW HALF OF THE GULF AND 1-3 FT IN THE NE HALF. WINDS WILL INCREASE TO 20 KT OVER THE NW GULF BY WED AHEAD OF LOW PRES FORMING OVER THE SOUTHERN PLAINS. WINDS WILL ALSO PULSE TO 20 KT ALONG AND OFFSHORE OF THE NW PORTION OF THE YUCATAN PENINSULA DURING THE OVERNIGHT HOURS THROUGH THE FORECAST PERIOD. ...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 VALUES FOR WAVE PARAMETERS. HIGH CONFIDENCE. A STATIONARY FRONT REACHING FROM EASTERN CUBA TO NE HONDURAS IS FORECAST TO BECOME DIFFUSE THROUGH TODAY PRIOR TO BECOMING A REMNANT SURFACE TROUGH BY MON MORNING. THIS SURFACE TROUGH WILL BE SUPPORTED BY AN APPROACHING UPPER TROUGH OVER THE NW CARIBBEAN AFTER THE FRONT WASHES OUT. MEANWHILE FARTHER EAST THE SUBTROPICAL RIDGE IS SHIFTED A LITTLE MORE SOUTHEASTWARD DUE TO A SERIES OF STRONG UPPER IMPULSES NORTH OF THE AREA. HIGH PRES WILL BUILD OVER THE EASTERN UNITED STATES AND MODELS REMAIN IN GOOD AGREEMENT SHOWING THAT THIS WILL INCREASE TRADE WINDS ACROSS THE CENTRAL CARIBBEAN TO INCLUDE THE EASTERN COAST OF COLOMBIA THROUGH WED. ASSOCIATED WAVE HEIGHTS BUILD 8 TO 11 FT TUE...THEN UP TO 12 FT WED AND THU. MODERATE TO FRESH TRADES WILL PERSIST OVER THE TROPICAL N ATLC WITH SEAS 5 TO 7 FT. ...SW N ATLANTIC INCLUDING THE BAHAMAS... MODEL PREFERENCE: 00Z ECMWF BLENDED WITH PREVIOUS OFFICIAL FORECAST. TAFB NWPS FOR SEAS. HIGH CONFIDENCE THROUGH MON...THEN MEDIUM CONFIDENCE THEREAFTER MOST PARTICULARLY WITH THE POSSIBLE FORMATION OF LOW PRES IN VICINITY OF BAHAMAS. A COLD FRONT EXTENDS FROM 31N58W TO EASTERN CUBA WILL DRIFT SE BEFORE STALLING THROUGH TODAY AND BECOMING DIFFUSE THROUGH LATE MONDAY. HIGH PRES OVER THE DEEP SOUTH STATES IS SHIFTING EASTWARD FOLLOWING THE FRONT...EVENTUALLY BUILDING OFF THE CAROLINA COAST OVER THE NEXT COUPLE OF DAYS. WINDS N OF 22N BEHIND THE FRONT HAVE DIMINISHED FROM YESTERDAY...CURRENTLY ONLY 10 TO 15 KT OUT OF THE NORTH. BUOY OBSERVATIONS ARE SHOWING 8 TO 10 FT SEAS IN NW SWELL OVER MOST OF THE ATLC WATERS NE BAHAMAS. MOST OF THIS WILL SUBSIDE TO LESS THAN 8 FT THROUGH MONDAY. THE FORECAST ISSUE FOR TUE THROUGH THU CONTINUES TO BE THE POSSIBLE DEVELOPMENT OF LOW PRES OVER THE NORTHERN BAHAMAS. SOME DISAGREEMENT CONTINUES 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 SOMEWHAT STRONGER SOLUTION...ALTHOUGH MORE IN LINE WITH THE MORE CONSERVATIVE ECMWF WHICH CONTINUES TO SHOW A MUCH WEAKER LOW LOCATED MORE TO THE SW CLOSER TO THE NORTHERN BAHAMAS BY WED MORNING...LIFTING N TO 31N77W BY EARLY FRI. THE ECMWF IS A GOOD COMPROMISE BETWEEN THE GFS AND THE UKMET WHICH SHOWS A MORE EASTERLY TRAJECTORY. 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.