000 AGXX40 KNHC 281737 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 137 PM EDT MON SEP 28 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: GLOBAL MODEL CONSENSUS. LATEST TAFB NWPS FOR WAVE PARAMETERS. HIGH CONFIDENCE. A CLOSED OFF UPPER LEVEL LOW IS DRIFTING EASTWARD ALONG THE NE TEXAS COAST WITH A NEGATIVELY TILTED UPPER TROUGH PIVOTING NORTHWARD OVER THE NE GULF. 1007 MB SURFACE LOW PRES CENTERED NEAR 25N87W IS MOVING NNE FROM NORTHERN YUCATAN AND WILL REACH THE FLORIDA BIG BEND AREA EARLY TUE BEFORE MOVING INLAND AND DISSIPATING. THE STRONG WESTERN UPPER FLOW IS SHEARING THE CONVECTION TO THE EAST OF THE CENTER...BUT ALSO ENHANCING THE THUNDERSTORMS OVER THE EASTERN GULF. STRONG SOUTHERLY SQUALLS ARE LIKELY IN THE EASTERN GULF THROUGH TONIGHT AS THE LOW PRES SHIFTS NORTH. THROUGH MID WEEK...GLOBAL MODELS ARE IN DECENT AGREEMENT SHOWING THE UPPER LOW OPENING INTO A TROUGH AND WEAKENING AS IT SHIFTS EAST ACROSS THE LOWER MISSISSIPPI VALLEY AND NORTHERN GULF. THE LOW PRES OVER THE NW GULF WILL WEAKEN TO A TROUGH AND DRIFT ACROSS THE GULF...LEAVING A DRIER PATTERN WITH GENTLE TO MODERATE W FLOW VEERING NW TO N. A WEAK COLD FRONT IS EXPECTED TO MOVE INTO THE NORTHERN GULF LATE THU NIGHT...THEN STALL AND BECOME DIFFUSE OVER THE CENTRAL GULF SAT. NO MAJOR DIFFERENCES IN MODEL OUTPUT. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... MODEL PREFERENCE: GLOBAL MODEL CONSENSUS. LATEST TAFB NWPS FOR WAVE PARAMETERS. HIGH CONFIDENCE. A 15 UTC ASCAT PASS INDICATED FRESH TRADE WINDS OFF COLOMBIA...INDICATIVE OF FRESH TO STRONG FLOW EXPECTED OFF WESTERN VENEZUELA AND NE COLOMBIA THROUGH TONIGHT AS A SURFACE RIDGE REACHES FROM THE N CENTRAL ATLC TO THE S CENTRAL CARIBBEAN. THE RIDGE IN THE ATLC WILL WEAKEN THROUGH TONIGHT HOWEVER...AS THE REMNANT LOW OF T.S. IDA DRIFTS WEST TOWARD A DEVELOPING T.D. ELEVEN LOCATED NE OF THE BAHAMAS. THIS WILL RESULT IN THE TRADE WINDS DIMINISHING ACROSS THE BASIN FOR THE REMAINDER OF THE WEEK. NO MAJOR DIFFERENCES IN MODEL OUTPUT. ...SW N ATLANTIC INCLUDING THE BAHAMAS... MODEL PREFERENCE: GLOBAL MODEL CONSENSUS. LATEST TAFB NWPS FOR WAVE PARAMETERS. MEDIUM CONFIDENCE. THE MAIN FORECAST ISSUE CONCERNS THE DEVELOPMENT...TRACK AND INTENSITY OF T.D. ELEVEN CENTERED NEAR 27N69W. T.D. ELEVEN HAS MAX WINDS TO 30 KT WITH GUSTS TO 40 KT...AND IS FORECAST TO INTENSIFY TO TROPICAL STORM STRENGTH WITH 40 KT BY THIS EVENING AS IT MOVES SLOWLY NNW. A BROAD SWATH OF CONVECTION COVERS THE AREA EAST OF 70W. ELSEWHERE TO THE WEST AND SOUTHWEST OF T.D. ELEVEN...GENERALLY GENTLE TO MODERATE WINDS PREVAIL. BUOY OBSERVATIONS INDICATE NE SWELL GENERATED FROM A LARGE SWATH OF STRONG E WINDS OVER THE SUBTROPICAL ATLC WATERS HAS REACHED FARTHER WEST THAN PREVIOUSLY ANTICIPATED...AND INITIAL FORECAST GRIDS HAVE BEEN ADJUSTED ACCORDINGLY. WAVE GUIDANCE INDICATES THE SWELL WILL NOT PUSH MUCH MORE TO THE WEST AND SOUTH AND WILL START TO DECAY BACK TO THE EAST THROUGH MID WEEK...WITH THE EXCEPTION OF WAVES GENERATED BY THE DEVELOPING TROPICAL STORM WITHIN A COUPLE OF HUNDRED MILES OF ITS CENTER. THE TROPICAL STORM WILL SHIFT N OF THE AREA BY EARLY THU...LEAVING LIGHT TO GENTLE BREEZES AND SEAS 4 TO 6 FT NE OF THE BAHAMAS INTO FRI. A COLD FRONT WILL MOVE INTO THE WATERS OFF NE FLORIDA FRI INTO SAT FOLLOWED BY MODERATE TO FRESH NORTHERLY FLOW AND SEAS TO 7 FT. SOME UNCERTAINTY PERSISTS IN MODEL OUTPUT ON THE INTENSITY AND SPEED OF MOVEMENT OF THE TROPICAL CYCLONE. THE OFFICIAL FORECAST IS A GENERAL BLEND OF GFS AND ECMWF GUIDANCE. $$ .WARNINGS...ANY CHANGES IMPACTING COASTAL NWS OFFICES WILL BE COORDINATED THROUGH AWIPS 12 PLANET CHAT OR BY TELEPHONE: .GULF OF MEXICO... NONE. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... NONE. .SW N ATLANTIC INCLUDING THE BAHAMAS... .AMZ113...ATLANTIC FROM 27N TO 31N BETWEEN 70W AND 77W... TROPICAL STORM WARNING TONIGHT INTO TUE NIGHT. .AMZ115...ATLANTIC FROM 27N TO 31N BETWEEN 65W AND 70W... TROPICAL STORM WARNING TONIGHT INTO TUE. $$ *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.