000 AGXX40 KNHC 200546 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 146 AM EDT SAT AUG 20 2016 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: GLOBAL MODEL CONSENSUS. MEDIUM-HIGH CONFIDENCE. A THERMAL TROUGH WILL DEVELOP OVER THE YUCATAN PENINSULA DURING THE LATE AFTERNOONS AND CONTINUE INTO THE EARLY EVENINGS. EXPECT FRESH NE-E WINDS TO DEVELOP ALONG THE NW COAST OF THE WESTERN YUCATAN PENINSULA BEGINNING IN THE LATE AFTERNOONS...AND ENDING BEFORE MIDNIGHT EACH NIGHT AS THE INVERTED TROUGH MOVES W-NW ACROSS THE SW GULF WATERS...ACCOMPANIED BY A ENE-ESE 15-20 KT WIND SHIFT...AND 4-5 FT SEAS. THE EXCEPTION WILL BE ON SUN AND MON NIGHTS WHEN THE GRADIENT WILL SUPPORT 20-25 KT CONDITIONS. THE TROUGH WILL LOSE IDENTITY NEAR 22N94W BY LATE EACH MORNING. OTHERWISE...A SURFACE HIGH OVER THE NE GULF WILL GRADUALLY SHIFT SE TO A POSITION JUST WSW OF TAMPA BAY LATE TONIGHT...THEN SHIFT SLOWLY NW REACHING A POSITION JUST ESE OF THE MISSISSIPPI DELTA BY MID WEEK... ALL THE WHILE EXTENDING A SURFACE TROUGH NW ACROSS THE NW COASTAL PLAINS. MODERATE E-SE RETURN FLOW EXPECTED TO DEVELOP DURING AFTERNOON PEAK HEATING OVER THE CENTRAL AND WESTERN GULF. MAINLY GENTLE TO MODERATE ANTICYCLONIC WINDS ELSEWHERE AROUND THE RIDGE THROUGH WED. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... MODEL PREFERENCE: GLOBAL MODEL CONSENSUS. MEDIUM-HIGH CONFIDENCE. A TROPICAL WAVE CURRENTLY ALONG 82W WILL PASS THROUGH THE NW CARIBBEAN TONIGHT WITH A SLIGHT ENHANCEMENT OF CONVECTION. A SECOND TROPICAL WAVE CURRENTLY ALONG 67W WILL RACE W THROUGH THE CENTRAL CARIBBEAN THROUGH TONIGHT REACHING THE W CARIBBEAN ON SUN AND MON ACCOMPANIED BY ISOLATED TSTMS. OTHERWISE...THE PRESSURE GRADIENT BETWEEN THE SUBTROPICAL SW ATLC RIDGE AND BROAD LOW PRESSURE OVER S AMERICA WILL MAINTAIN FRESH TO STRONG NE-E TRADES...WITH SEAS TO 11 FT...ACROSS THE S-CENTRAL CARIBBEAN THROUGH WED. EXPECT NE WINDS TO PULSE TO NEAR GALE AT 30 KT JUST OFF THE NW COAST OF COLOMBIA TONIGHT. MODERATE TRADES ARE EXPECTED ELSEWHERE...EXCEPT ACROSS THE TROPICAL WATERS E OF THE WINDWARDS BEGINNING ON TUE AS A TROPICAL LOW CURRENTLY WELL E OF THE AREA NEAR 11N34W WILL REACH NEAR 12N55W ON TUE AFTERNOON. THIS LOW WILL ENCOUNTER MORE FAVORABLE CONDITIONS FOR TROPICAL CYCLONE DEVELOPMENT IN 3 TO 5 DAYS. THE GRIDS CURRENTLY DEPICT STRONG E WINDS SHIFTING ACROSS THE TROPICAL WATERS FROM 13-18N TUE THROUGH WED EVENING...AND STRONG E WINDS SHIFTING THROUGH THE VIRGIN ISLAND AREA LATE WED NIGHT INTO THU. ...SW N ATLANTIC INCLUDING THE BAHAMAS... MODEL PREFERENCE: GLOBAL MODEL CONSENSUS. MEDIUM-HIGH CONFIDENCE. A BROAD LOW LEVEL TROUGH OVER THE NE DISCUSSION WATERS WILL MOVE E SLOWLY E TODAY AND FILL EARLY SUN. A NE TO SW ORIENTATED RIDGE CURRENTLY ACROSS THE NW WATERS W OF THE TROUGH...WILL SHIFT SE IN THE WAKE OF THE TROUGH...WITH A SURFACE HIGH DEVELOPING NEAR 27N75W TONIGHT WITH A RIDGE EXTENDING W TO CENTRAL FL. THE RIDGE WILL WEAKEN AND SHIFT S TO ALONG 25N ON SUN NIGHT INTO MON ALLOWING A WEAK COLD FRONT...OR TROUGH...TO SWEEP E ACROSS THE WATERS N OF THE 27N...AND EVENTUALLY STALLING FROM 31N68W TO 26N73W ON TUE NIGHT. WINDS ASSOCIATED WITH TS FIONA WILL EFFECT THE NE CORNER OF AMZ127 WHERE W-NW 20-30 KT WINDS ARE EXPECTED ON SUN NIGHT AS THE W PERIPHERY OF FIONA BRUSHES THE NE CORNER OF AMZ127. FIONA WILL WEAKEN AS IT TRACKS NNW THROUGH THE DISCUSSION WATERS BETWEEN 55-65W ON SUN NIGHT THROUGH WED. AS THE REMNANTS OF FIONA PASS NEAR 31N63W LATE WED...THE NEARLY STATIONARY SURFACE TROUGH TO THE W WILL BEGIN TO SHIFT W ACROSS THE WATERS N OF 25N...AND PASS THROUGH THE NW BAHAMAS LATE THU. BY THEN...THE NEXT TROPICAL SYSTEM WILL BE NE MOVING WNW ACROSS THE NE CARIBBEAN INTO THE ATLC WATERS S OF 23N BETWEEN 64-71W... ACCOMPANIED BY E-SE 20-25 KT WINDS AND SEAS BUILDING TO ABOUT 10 FT. THIS SECOND SYSTEM HAS THE POTENTIAL FOR TROPICAL CYCLONE FORMATION ON DAY 3-5. $$ .WARNINGS...ANY CHANGES IMPACTING COASTAL NWS OFFICES WILL BE COORDINATED THROUGH AWIPS II COLLABORATION CHAT OR BY TELEPHONE: .GULF OF MEXICO... NONE. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... NONE. .SW N ATLANTIC INCLUDING THE BAHAMAS... NONE. $$ *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.