000 AGXX40 KNHC 280710 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 310 AM EDT SUN SEP 28 2014 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: LATEST PREVIOUS/OFFICIAL BLENDED WITH THE GFS. MWW3 AND TAFB-NWPS USED TO ADJUST WAVE PARAMETERS. MEDIUM CONFIDENCE. THE 06Z SURFACE ANALYSIS DEPICTS A STATIONARY FRONT STRETCHED FROM E TO W ACROSS THE NORTHERN GULF IN AN AREA OF CONFLUENCE SEEN IN THE SURFACE OBSERVATIONS. A PLETHORA OF VORTS ALOFT LIE INVOF THE BOUNDARY. THE MODELS HANDLE THIS ENERGY SLIGHTLY DIFFERENTLY...BUT THE GENERAL FORECAST CALLS FOR NEW LOW PRES TO FORM ALONG THE FRONT TONIGHT OVER THE N CENTRAL GULF...WITH THE BOUNDARY MOVING EASTWARD ACROSS THE GULF TONIGHT INTO TUE. THE 00Z GFS...UKMET AND CMC ARE IN REASONABLE AGREEMENT ON THE TIMING OF THE LOW MOVING E ALONG THE NORTHERN GULF COAST...WITH THE WEAKER 12Z/27 ECMWF DEPICTING A SLOWER SOLUTION. WHILE CONFIDENCE IS LOWERED IN THE GFS SOLUTION BECAUSE IT GENERATES BETWEEN 0.5-1.0 INCHES OF PRECIP THAT IS UNACCOUNTED FOR BY CONVECTIVE PROCESSES NEAR THE MISSISSIPPI/ALABAMA/FLORIDA COAST. HOWEVER...ITS FEATURES SEEM AND HANDLING OF THE VORT ENERGY APPEAR TO BE AS GOOD AS ANY OF THE OTHER 00Z MODELS. THE BEST CHANCE FOR WINDS TO MEET ADVISORY CRITERIA WILL BE TODAY PRIMARILY IN THE COASTAL WATERS TO THE N OF THE LOW PRES SYSTEM CURRENTLY NEAR BROWNSVILLE TEXAS. RADAR IMAGERY SHOWS A TIGHTLY WOUND STRUCTURE TO THIS SMALL SYSTEM WHICH IS EXPECTED TO WEAKEN THROUGH THE DAY. OTHERWISE...WINDS AND SEAS WILL REMAIN BELOW ADVISORY CRITERIA THROUGH THU NIGHT WITH HIGH PRES BUILDING BEHIND THE FRONT WED AND THU. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... MODEL PREFERENCE: LATEST GFS BLENDED WITH PREVIOUS/OFFICIAL FORECAST. TAFB-NWPS AND MWW3 USED TO ADJUST WAVE PARAMETERS. HIGH CONFIDENCE. THE SUBTROPICAL HIGH HAS BEEN COMPROMISED BY A DEEP-LAYERED TROUGH STRETCHED FROM THE CENTRAL ATLC THROUGH THE NE CARIBBEAN INTO THE SW CARIBBEAN. THIS TROUGH IS NOW WEAKENING AS NEW ENERGY CURRENTLY NEAR BERMUDA MOVES INTO THE BACKSIDE OF THE BROAD TROUGH. THIS ENERGY WILL REMAIN OVER N WATERS...ALLOWING HEIGHTS TO GRADUALLY BUILD ALONG WITH THE PRES GRADIENT. WINDS HAVE ALREADY BEGUN TO PICK UP BEHIND THE TROPICAL WAVE OVER THE CENTRAL CARIBBEAN WITH RECENT ASCAT PASSES SHOWING 20 KT WINDS JUST N OF THE PARAGUANA PENINSULA OF VENEZUELA. THE 00Z GEFS SHOWS UP TO A 70 PERCENT CHANCE OF WINDS MEETING ADVISORY CRITERIA IN S WATERS ALONG 70W SUN NIGHT INTO EARLY MON. BECAUSE WINDS HAVE ALREADY INCREASED IN THIS AREA AND THE PROBABILITIES CONTINUE TO RISE...ADJUSTED THE FORECAST TO CALL FOR WINDS MEETING ADVISORY CRITERIA OVERNIGHT TONIGHT IN ZONE AMZ033 BY USING THE 00Z GFS. WITH THE GFS GENERALLY PREFERRED WITH THE PATTERN TO THE N THROUGH THU NIGHT...IT SEEMS REASONABLE TO USE IT IN THE CARIBBEAN FOR THE FORECAST AS WELL. ...SW N ATLANTIC INCLUDING THE BAHAMAS... MODEL PREFERENCE: LATEST PREVIOUS/OFFICIAL BLENDED WITH THE GFS. MWW3 AND TAFB-NWPS USED TO ADJUST WAVE PARAMETERS. MEDIUM CONFIDENCE. THERE IS DISAGREEMENT AMONG THE MODELS WITH THE SMALL-SCALE PERTURBATIONS EXPECTED ALONG THE WEAK FRONTAL BOUNDARY OVER N WATERS AND JUST N OF THE AREA THROUGH MON. THESE FEATURES WILL HAVE LITTLE IMPACT ON WHETHER WINDS AND SEAS WILL REACH ADVISORY CRITERIA. THE GFS SOLUTION IS AS GOOD AS ANY HERE. LARGER DIFFERENCES COME INTO PLAY AS THE LOW EXPECTED OVER THE N CENTRAL GULF OF MEXICO TONIGHT MOVES INTO THE ATLC OVERNIGHT MON NIGHT. THE NEW 00Z ECMWF HAS COME INTO BETTER AGREEMENT ON CARRYING THE LOW EASTWARD MORE QUICKLY...BUT IS NOT AS DEEP AS THE GFS AND UKMET. THE TREND IN THE ECMWF IS ALSO A TREND TOWARD THE MORE EASTERLY 00Z GEFS AND EC ENS MEANS. CONFIDENCE WANES IN THE GFS WITH THE STRENGTH OF THE LOW AS IT CROSSES LAND AND MOVES INTO THE ATLC MON NIGHT THROUGH TUE NIGHT...WITH THE GFS GENERATING CONSIDERABLE AMOUNTS OF PRECIP NOT GENERATED BY CONVECTIVE FACTORS. BLENDING WITH THE PREVIOUS/OFFICIAL HELPS TO DULL DOWN THE GFS HERE AS WELL AS IN ZONE AMZ115 WED AND THU WHEN THE GFS BECOMES A SLIGHT OUTLIER WITH THE STRONG WINDS IT DEVELOPS ASSOCIATED WITH VORT ENERGY ON THE LEADING EDGE OF THE UPPER TROUGH SUPPORTING THE MAIN LOW TO THE NW. $$ .WARNINGS...ANY CHANGES IMPACTING COASTAL NWS OFFICES WILL BE COORDINATED THROUGH AWIPS 12 PLANET CHAT OR BY TELEPHONE: .GULF OF MEXICO... NONE. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... NONE. .SW N ATLANTIC INCLUDING THE BAHAMAS... NONE. $$ *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 SCHAUER. NATIONAL HURRICANE CENTER.