000 AGXX40 KNHC 300544 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 144 AM EDT TUE JUN 30 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: FOR WINDS LATEST GFS BLENDED WITH PREVIOUS OFFICIAL WHICH WAS A GFS/ECMWF BLEND. TAFB NWPS USED FOR WAVE PARAMETERS. BLENDED INTO PREVIOUS OFFICIAL. HIGH CONFIDENCE. AN E-W RIDGE EXTENDS FROM SW FL TO THE NE TX COAST WITH A SURFACE HIGH DEVELOPING ALONG THE RIDGE OVER THE E GULF WATERS DURING THE LATE AFTERNOONS AND INTO THE EARLY EVENINGS AS AFTERNOON HEAT TROUGHING DEVELOPS OVER THE FL PENINSULA AND TEMPORARILY SEPARATES THE GULF RIDGE SEGMENT FROM THE ATLC RIDGE. LIGHT-GENTLE ANTICYCLONIC WINDS EXPECTED WITHIN 150 NM OF THE RIDGE AXIS WITH MODERATE E-SE WINDS EXPECTED AROUND THE S AND SW PERIPHERY OF THE RIDGE...AND SW-W 10-15 KT WINDS N OF THE RIDGE OVER THE FAR NE WATERS. THE EXCEPTION IS THE THERMAL TROUGH 20-25 KT ENHANCEMENT DEVELOPING ALONG THE NW COAST OF THE YUCATAN PENINSULA EACH EVENING THAT WILL MOVE WNW AS AN INVERTED TROUGH DURING THE LATE NIGHT AND EARLY DAYLIGHT HOURS...AND DISSIPATE BY EARLY AFTERNOON. THE TROUGH THAT DEVELOPED ON MON EVENING IS CURRENTLY ACCOMPANIED BY A LINE OF TS S OF 21N ALONG 95-96W...BUT IS EXPECTED TO DISSIPATE BY DAYLIGHT THIS MORNING. GUIDANCE STILL SUGGESTS A SIGNIFICANT THERMAL EVENT WILL SET UP THIS EVENING WITH E-SE 20-25 KT WINDS ACROSS THE GULF WATERS S OF 23.5N BETWEEN 90-95W BY LATE TONIGHT. AN UPPER CYCLONE HAS MOVED E TO NEAR 23N87W WITH UPPER DIFFLUENCE OVER ITS E SEMICIRCLE PROVIDING FAVORABLE UPPER SUPPORT FOR MAINLY SHOWERS OVER THE SE GULF...AND DENOTED IN WEATHER GRIDS FOR TODAY. THE RIDGE WILL CONTINUE TO SHIFT N BECOMING ORIENTATED FROM TAMPA BAY TO NE TEXAS THIS AFTERNOON WHERE IT WILL MEANDER THROUGH THU...THEN SHIFT FURTHER N TO A POSITION FROM CEDAR KEY FL TO THE MS DELTA EARLY THIS WEEKEND. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... MODEL PREFERENCE: FOR WINDS LATEST GFS BLENDED WITH PREVIOUS OFFICIAL WHICH WAS A GFS/ECMWF BLEND. TAFB NWPS USED FOR WAVE PARAMETERS. MEDIUM-HIGH CONFIDENCE. ATLC RIDGE N OF THE AREA COMBINED WITH LOW PRESSURE OVER NW COLOMBIA WILL CONTINUE TO MAINTAIN A TIGHT PRESSURE GRADIENT ACROSS THE CARIBBEAN BASIN THROUGH TONIGHT...THEN THE GRADIENT IS FORECAST TO BEGIN TO WEAKEN. THE NOCTURNAL PULSES TO GALE FORCE IS EXPECTED TO CONTINUE ALONG THE NW COAST OF COLOMBIA THROUGH TONIGHT...WITH SEAS BUILDING TO AS HIGH AS 17 FT. MINIMAL GALE CONDITIONS AREA EXPECTED AGAIN BRIEFLY ON THU NIGHT. THE N EXTENSION OF A TROPICAL WAVE WILL PASS THROUGH THE GULF OF HONDURAS TODAY...BUT IS CURRENTLY LACKING CONVECTION. THE NOCTURNAL INCREASE OF TRADES TO 20-25 KT ACROSS THE WESTERN GULF OF HONDURAS IS EXPECTED AGAIN TONIGHT...WITH THESE NOCTURNAL CONDTIONS BEGINNING AGAIN ON THU NIGHT. A SECOND TROPICAL WAVE WILL RACE THROUGH THE E CARIBBEAN TODAY...THROUGH THE CENTRAL CARIBBEAN TONIGHT AND WED...AND THE W CARIBBEAN LATE IN THE WEEK. A THIRD TROPICAL WAVE WILL ENTER THE E CARIBBEAN TONIGHT... REACH THE CENTRAL CARIBBEAN WATERS MID WEEK. ...SW N ATLANTIC INCLUDING THE BAHAMAS... MODEL PREFERENCE: FOR WINDS LATEST GFS BLENDED WITH PREVIOUS OFFICIAL WHICH WAS GFS/ECMWF BLEND. TAFB NWPS USED FOR SEAS HEIGHTS AND PRIMARY PERIOD. MEDIUM-HIGH CONFIDENCE. A RIDGE EXTENDING FROM 31N59W TO SE FL WILL SHIFT SLIGHTLY N TO A POSITION FROM 30N65W TO CENTRAL FL ON WED AND FROM 29N65W TO PORT CANAVERAL LATE IN THE WEEK. SOUTHERLY 20-25 KT KT FLOW N OF 30N BETWEEN 72-76W TODAY WILL DIMINISH BY THIS EVENING WITH 15- 20 KT CONDITIONS EXPECTED N OF THE RIDGE THROUGH WED NIGHT. THE 20-25 KT CONDITIONS WILL DEVELOP N OF THE RIDGE AGAIN ON THU AND FRI NIGHTS AS WEAK TROUGHS MOVE OFF THE SE GA COAST...BUT IMMEDIATELY STALL AND WASH OUT. MODERATE E-SE TRADES ARE OBSERVED S OF THE RIDGE...EXCEPT INCREASING TO 20-25 KT ALONG THE N COAST OF HISPANIOLA AND THE ATLC APPROACH TO THE WINDWARD PASSAGE DURING THE LATE AFTERNOONS INTO EARLY EVENINGS. $$ .WARNINGS...ANY CHANGES IMPACTING COASTAL NWS OFFICES WILL BE COORDINATED THROUGH AWIPS 12 PLANET CHAT OR BY TELEPHONE: .GULF OF MEXICO... NONE. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... .AMZ031...CARIBBEAN FROM 11N TO 15N BETWEEN 72W AND 80W INCLUDING COLOMBIA BASIN... GALE WARNING EARLY TODAY INTO TONIGHT. GALE CONDITIONS POSSIBLE THU NIGHT. .SW N ATLANTIC INCLUDING THE BAHAMAS... NONE. $$ *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.