000 AGXX40 KNHC 270705 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 305 AM EDT SAT SEP 27 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 THROUGH MON NIGHT THEN WITH THE ECMWF TUE THROUGH WED NIGHT. MWW3 USED TO ADJUST WAVE PARAMETERS. MEDIUM CONFIDENCE. THE 0256Z ASCAT-A PASS SHOWED SOME 20-25 KT WINDS IN THE NW GULF AND BUOY 42360 HAS REPORTED 23 KT E-NE WINDS AND 5-6 FT SEAS FOR THE LAST 4 HOURS. THE MODELS ARE ON THE WEAK SIDE WITH THE WINDS HERE INITIALLY...BUT THERE IS GENERAL AGREEMENT AMONG THE 00Z GFS AND UKMET AND THE 12Z/26 ECMWF THAT A FRESH TO STRONG BREEZE WILL SHIFT E ACROSS THE GULF BY MORNING AND THEN BACK W THROUGH THIS EVENING. THE GFS SOLUTION WAS THE STRONGEST AND CLOSEST TO THE INITIAL CONDITIONS. IT WAS USED TO ADJUST THE GRIDS HERE EARLY IN THE PERIOD. ON SUN...THE REMNANTS OF THE STATIONARY FRONT THAT WAS DRAPED ACROSS THE NORTHERN GULF FRI WILL MOVE WESTWARD ACROSS THE CENTRAL GULF. NEW LOW PRES IS EXPECTED TO FORM ALONG IT SUN MORNING OVER THE N CENTRAL GULF AND SEND THE TROUGH EASTWARD ACROSS THE GULF SUN NIGHT INTO TUE. THE GFS IS SLOWER TO CARRY THE LOW EASTWARD INTO THE ATLC THAN THE UKMET AND 12Z/26 ECMWF BY TUE. IT IS ALSO SLOWER THAN THE 18Z GEFS AND 12/26 EC ENS MEAN. THEREFORE...ADJUSTED THE FORECAST FROM TUE ONWARD TOWARD THE ECMWF. ...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. WINDS AND SEAS ARE RATHER TRANQUIL ACROSS THE CARIBBEAN UNDER A WEAK PRESSURE GRADIENT WITH THE SUBTROPICAL HIGH COMPROMISED BY A DEEP-LAYERED TROUGH STRETCHED FROM THE CENTRAL ATLC THROUGH THE NE CARIBBEAN INTO THE S CENTRAL CARIBBEAN. THIS TROUGH IS EXPECTED TO GRADUALLY WEAKEN BEGINNING OVER THE WEEKEND. NEW ENERGY IS EXPECTED TO MOVE INTO THE BACKSIDE OF THE BROAD TROUGH BUT WILL REMAIN OVER N WATERS...ALLOWING HEIGHTS TO GRADUALLY BUILD ALONG WITH THE PRES GRADIENT. THE 00Z GEFS SHOWS UP TO A 40 PERCENT CHANCE OF WINDS MEETING ADVISORY CRITERIA IN S WATERS ALONG 70W SUN NIGHT INTO EARLY MON...BUT THE PROBABILITIES INCREASE TO NEARLY 100 PERCENT MON NIGHT INTO EARLY TUE AS HIGH PRES BECOMES BETTER ESTABLISHED OVER THE CENTRAL ATLC. THE UKMET AND ECMWF NEVER STAMP OUT 25 KT WINDS IN THE S CENTRAL CARIBBEAN. THIS SEEMS UNLIKELY GIVEN THE STRENGTHENING RIDGE TO THE N. THE GFS IS USUALLY STRONGER THAN THE OTHER MODELS IN THE S CENTRAL CARIBBEAN UNDER THIS TYPE OF PATTERN AND GENERALLY PANS OUT BETTER. THE GFS IS PREFERRED FOR ADJUSTING THE FORECAST. ...SW N ATLANTIC INCLUDING THE BAHAMAS... MODEL PREFERENCE: LATEST PREVIOUS/OFFICIAL BLENDED WITH THE GFS THROUGH MON NIGHT THEN WITH THE ECMWF TUE THROUGH WED NIGHT. MWW3 USED TO ADJUST WAVE PARAMETERS WITH EC WAVE ADDED TUE THROUGH WED NIGHT. HIGH CONFIDENCE THROUGH MON NIGHT THEN MEDIUM CONFIDENCE. THERE IS DISAGREEMENT AMONG THE MODELS IN THE SMALL-SCALE PERTURBATIONS EXPECTED ALONG THE WEAK FRONTAL BOUNDARY OVER N WATERS AND JUST N OF THE AREA. 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 SUN MOVES INTO THE ATLC OVERNIGHT MON NIGHT. THE GFS IS SLOWER TO CARRY THE LOW EASTWARD THAN THE ECMWF OR THE 18Z GEFS AND 12Z EC ENS MEAN SOLUTIONS. THE ECMWF IS IN BETTER AGREEMENT WITH THE MEANS. WILL ADJUST THE FORECAST TOWARD THE ECMWF TUE ONWARD TO BE MORE IN LINE WITH THE ENSEMBLE CONSENSUS. $$ .WARNINGS...ANY CHANGES IMPACTING COASTAL NWS OFFICES WILL BE COORDINATED THROUGH AWIPS 12 PLANET CHAT OR BY TELEPHONE: .GULF OF MEXICO... NONE. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... NONE. .SW N ATLANTIC INCLUDING THE BAHAMAS... NONE. $$ *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.