000 AGXX40 KNHC 091856 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 256 PM EDT WED SEP 9 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. ----------------------------------------------------------------- PREVIOUS DISCUSSION... ...GULF OF MEXICO... MODEL PREFERENCE: 12Z GFS AND 00Z ECMWF BLENDED INTO PREVIOUS OFFICIAL. TAFB NWPS USED FOR SEAS HEIGHTS AND PRIMARY WAVE PERIOD WITH MANUAL ADJUSTMENTS TO MATCH OBSERVATIONS. MEDIUM-HIGH CONFIDENCE. AT THE LOW LEVELS A RIDGE EXTENDS FROM E TO W ALONG 27N WITH SOUTHERLY RETURN FLOW AT 10-15 KT ACROSS THE W-CENTRAL WATERS TO THE W OF 95W. AS A THERMAL TROUGH IS DEVELOPING OVER FL THIS AFTERNOON AND EXPECT A SURFACE HIGH TO FORM ALONG THE RIDGE NEAR 26.5N83W AND LIKELY REDEVELOP AGAIN ON THU AFTERNOON...BUT BY THEN THE RIDGE WILL HAVE RETRACTED E ALLOWING A TROUGH TO DIP INTO THE N-CENTRAL WATERS AND MOVE E ON FRI. THE TROUGH IS EXPECTED TO ONLY BE ACCOMPANIED BY A SW-W-NW 5-10 KT WIND SHIFT. FORECAST THE TROUGH TO STALL FROM THE FL BIG BEND TO CENTRAL GULF ON SUN WITH STRONGER HIGH PRESSURE BUILDING OVER THE NW GULF SUPPORTING NE 10-15 KT WINDS LATE SUN INTO EARLY SUN NIGHT. FURTHER S...AN INVERTED THERMAL TROUGH WILL DEVELOP EACH AFTERNOON OVER THE YUCATAN PENINSULA...AND THEN MOVE W-NW ACROSS THE SW GULF WATERS...GENERALLY TO THE S OF 22N BETWEEN 90-93W DURING THE EVENING THROUGH LATE NIGHT HOURS...REACHING ALONG 94- 95W DURING THE EARLY DAYLIGHT HOURS...AND THEN DISSIPATING BY EARLY AFTERNOON. EXPECT THIS TROUGH TO BE ACCOMPANIED BY A NE-E- SE 15-20 KT NOCTURNAL EVENTS THROUGH SAT NIGHT...THEN GUIDANCE SUGGESTS A SLIGHTLY STRONGER EVENT TO OCCUR ON SUN NIGHT. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... MODEL PREFERENCE: 12Z GFS AND 00Z ECMWF BLENDED INTO PREVIOUS OFFICIAL. TAFB NWPS USED FOR SEAS HEIGHTS AND PRIMARY WAVE PERIOD WITH MANUAL ADJUSTMENTS TO MATCH OBSERVATIONS. MEDIUM-HIGH CONFIDENCE. THE ATLC RIDGE N OF THE AREA COMBINED WITH LOW PRESSURE OVER NW COLOMBIA WILL CONTINUE TO ENHANCE FRESH TRADES ACROSS THE THE S- CENTRAL WATERS...EXCEPT INCREASING TO STRONG WITHIN ABOUT 240 NM OF THE COLOMBIAN COAST TONIGHT INTO THU MORNING...BUILDING COMBINED SEAS TO 7-11 FT. THE GRADIENT IS EXPECTED TO RELAX ON THU SUPPORTING ONLY 15-20 KT NOCTURNAL EVENTS...WITH PERHAPS A SMALL AREA OF 20-25 KT FORMING WITHIN 30 NM OF THE EXTREME N COAST OF COLOMBIA ON THU NIGHT. GUIDANCE IS SUGGESTING AN INCREASE TO 20-25 KT AGAIN ON SUN NIGHT WITHIN 60 NM OF THE FAR N COAST OF COLOMBIA...AND ALSO ALONG THE FAR NW COAST OF VENEZUELA. A TROPICAL WAVE IN THE CENTRAL CARIBBEAN WILL PASS THROUGH THE W CARIBBEAN ON THU AND FRI WITH LITTLE IMPACTS. A SECOND TROPICAL WAVE IS ENHANCING CONVECTION W OF THE WAVE AXIS ACROSS THE TROPICS WITHIN ABOUT 90 NM OF 11N62W. THIS WAVE WILL ENTER THE SE CARIBBEAN TONIGHT...REACH THE CENTRAL CARIBBEAN ON WED NIGHT THROUGH THU NIGHT...AND PASS THROUGH THE W CARIBBEAN THIS UPCOMING WEEKEND. REMNANTS OF GRACE WILL ARRIVE NEAR 15N55W LATE WED NIGHT...REACH THE LEEWARDS EARLY FRI...AND REACH NEAR PUERTO RICO ON FRI NIGHT. SOME ENHANCEMENT OF WINDS AND INCREASED PRECIPITATION IS ANTICIPATED. ...SW N ATLANTIC INCLUDING THE BAHAMAS... MODEL PREFERENCE: 12Z GFS AND 00Z ECMWF BLENDED INTO PREVIOUS OFFICIAL. TAFB NWPS USED FOR SEAS HEIGHTS AND PRIMARY WAVE PERIOD WITH MANUAL ADJUSTMENTS TO MATCH OBSERVATIONS. MEDIUM-HIGH CONFIDENCE. TROPICAL DEPRESSION EIGHT HAS SEEN LITTLE CHANGE TODAY AS THE SYSTEM IS SHEARED AND HAS ALL DEEP CONVECTION ON EASTERN SEMICIRCLE. THE SYSTEM WILL MOVE N OF THE AREA THIS EVENING AND IS EXPECTED TO STRENGTHEN TO A TROPICAL STORM WARNING. AS THE CYCLONE LIFTS N IT WILL DRAG A TROUGH SE ACROSS THE WATERS N OF 25N E OF 70W. A SURFACE HIGH IS AT 29N74W WITH A RIDGE EXTENDING SW TO FORT PIERCE FL...AND A RIDGE ALSO EXTENDS SE TO NEAR 24N66W. THE HIGH IS EXPECTED TO MEANDER THROUGH THU NIGHT...AND LOSE IDENTITY ON FRI WITH A MORE DOMINATE RIDGE EXTENDING FROM 30N55W TO 27N65W TO FORT PIERCE FL. THE RIDGE WILL SHIFT TO A PSN FROM 31N63W TO THE NW BAHAMAS ON SUN. SW FLOW N OF THE RIDGE WILL INCREASE TO 10-15 KT ON THU NIGHT WITH LITTLE CHANGE THROUGH SAT...THEN INCREASE TO 15-20 KT AHEAD A OF A WEAK COLD FRONT MOVING OFF THE NE FL COAST LATE SAT NIGHT. EXPECT E-SE 10-15 KT FLOW ACROSS THE TROPICAL WATERS S OF THE RIDGE EXCEPT INCREASING TO E AT 15-20 KT ALONG THE N COAST OF HISPANIOLA AND THE ATLC APPROACH TO THE WINDWARD PASSAGE DURING THE EVENINGS THE EASTERLY TRADES WILL INCREASE TO 15-20 KT ACROSS THE TROPICS WELL E OF THE LEEWARDS...NEAR 20N56W ON THU NIGHT IN ADVANCE OF REMNANTS OF GRACE WHICH WILL REACH THE VIRGIN ISLAND AREA LATE FRI NIGHT..THESE 15-20 KT CONDITIONS WILL SPREAD N ACROSS THE TROPICS S OF 22N BETWEEN 65W AND 75W ON SAT AND SUN. $$ .WARNINGS...ANY CHANGES IMPACTING COASTAL NWS OFFICES WILL BE COORDINATED THROUGH AWIPS 12 PLANET CHAT OR BY TELEPHONE: .GULF OF MEXICO... NONE. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... NONE. .SW N ATLANTIC INCLUDING THE BAHAMAS... NONE. $$ *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 LANDSEA/NELSON. NATIONAL HURRICANE CENTER.