000 AGXX40 KNHC 200752 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 352 AM EDT SUN SEP 20 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: GFS BLENDED WITH PREVIOUS OFFICIAL FORECAST. NWPS BLENDED WITH PREVIOUS OFFICIAL FOR WAVES. HIGH CONFIDENCE. SHARP UPPER TROUGH PERSISTS FROM OUTER BANKS OF NORTH CAROLINA ACROSS THE SE GULF TO THE BAY OF CAMPECHE...SUPPORTING A SURFACE TROUGH ACROSS SOUTH FLORIDA. THIS HAS SHUNTED MUCH OF THE DEEP LAYER MOISTURE IN THE EASTERN GULF FARTHER EAST...ALLOWING SHOWERS AND THUNDERSTORMS TO DIMINISH. A WEAK SURFACE RIDGE OVER THE NW GULF WILL SHIFT EAST TODAY THEN WEAKEN TONIGHT AS A WEAK COLD FRONT MOVES INTO THE LOWER MISSISSIPPI VALLEY. THE FRONT WILL BECOME DIFFUSE AS IT STALLS OVER THE COASTAL WATERS OF THE NORTHERN GULF THROUGH LATE MONDAY. THE WEAK PRES PATTERN OVER THE GULF WILL ALLOW GENERALLY LIGHT WINDS WITH SEAS 2 TO 4 FT THROUGH MID WEEK. NO MAJOR DIFFERENCES IN MODEL OUTPUT. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... MODEL PREFERENCE: GFS BLENDED WITH PREVIOUS OFFICIAL FORECAST. NWPS BLENDED WITH PREVIOUS OFFICIAL FOR WAVES. HIGH CONFIDENCE. A WEAK SUBTROPICAL RIDGE PERSISTS N OF THE AREA...RESULTING IN DIMINISHED TRADE WINDS OVER THE CARIBBEAN BASIN AND TROPICAL N ATLC. MODERATE TO FRESH TRADES ARE EXPECTED OFF COLOMBIA...WITH GENTLE TO MODERATE WINDS OVER THE REMAINDER OF THE CARIBBEAN AND MUCH OF THE TROPICAL N ATLC. WINDS AND SEAS ARE EXPECTED TO REMAIN IN BELOW AVERAGE ACROSS THE REGION THROUGH EARLY NEXT WEEK. TRADE WINDS WILL START TO INCREASE OVER THE S CENTRAL CARIBBEAN INTO MID WEEK AS RIDGING BUILD NORTH OF AREA. ...SW N ATLANTIC INCLUDING THE BAHAMAS... MODEL PREFERENCE: LATEST GFS BLENDED WITH PREVIOUS OFFICIAL. NWPS BLENDED WITH PREVIOUS FORECAST FOR WAVES. HIGH CONFIDENCE THROUGH EARLY NEXT WEEK THEN MODERATE CONFIDENCE. A SURFACE TROUGH EXTENDS FROM A LOW NEAR 32N76W TO SOUTH FLORIDA. A 02 UTC ASCAT INDICATES A BAND OF FRESH NORTHERLY WINDS WEST OF THE TROUGH N OF 30N. THE LOW WILL DRIFT SLOWLY NORTHEAST TO EAST THROUGH MON...ALLOWING THE FRESH NORTHERLY WINDS TO DIMINISH THROUGH EARLY NEXT WEEK. HIGH PRES BUILDS OVER THE EASTERN UNITED STATES BY MID WEEK...TIGHTENING THE GRADIENT AND ALLOWING A INCREASED N TO NE WINDS ALONG THE CAROLINA AND GEORGIA COASTLINES. THERE IS LESS AGREEMENT THAN EARLIER AMONG MAJOR MODELS WITH REGARD TO HOW FAR SOUTH THESE WINDS WILL PENETRATE S OF 31N. THE FORECAST FAVORS GFS AND UKMET GUIDANCE OVER THE WEAKER ECMWF WITH A RETURN OF FRESH TO STRONG NE FLOW TO THE WATERS OFF NE FLORIDA AND NORTH OF THE BAHAMAS BY MID WEEK. THE STRONGER WINDS WILL BE ACCOMPANIED BY NE SWELL TO 8 FT N OF 30N BY WED. WEAK HIGH PRES ELSEWHERE WILL MAINTAIN MODEST WINDS AND SEAS THROUGH THE PERIOD. $$ .WARNINGS...ANY CHANGES IMPACTING COASTAL NWS OFFICES WILL BE COORDINATED THROUGH AWIPS 12 PLANET CHAT OR BY TELEPHONE: .GULF OF MEXICO... NONE. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... NONE. .SW N ATLANTIC INCLUDING THE BAHAMAS... NONE. $$ *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.