000 AGXX40 KNHC 301839 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 239 PM EDT WED SEP 30 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: 12Z GFS BLENDED WITH PREVIOUS OFFICIAL. FOR WAVEHEIGHTS USED LATEST TAFB NWPS WAVE PARAMETERS. HIGH CONFIDENCE. A SHARP UPPER TROUGH IS OVER THE FAR WESTERN GULF FROM LOUISIANA TO NE MEXICO. THIS TROUGH SUPPORTS A WEAK 1010 MB LOW NEAR 26N93W WITH A TROUGH EXTENDING NE TO THE FLORIDA PANHANDLE. THE LOW WILL WEAKEN FURTHER TO A TROUGH TONIGHT. ONLY SCATTERED SHOWERS AND ISOLATED TSTMS ARE NOTED OVER MAINLY THE SE GULF PORTION WITH ISOLATED SHOWERS AND TSTMS ALONG THE TROUGH. THE BUOY OBSERVATIONS SHOW NE WINDS OF 15 KT BEHIND THE TROUGH WITH SEAS OF 3-4 FT. SE OF THE TROUGH...SEAS ARE 1-2 FT. GLOBAL MODELS INDICATE THE UPPER TROUGH WILL DE-AMPLIFY SLIGHTLY AS IT DRIFTS E ACROSS THE GULF THROUGH EARLY THU...THEN BE REPLACED BY A MUCH DEEPER TROUGH LATE THU AND POTENTIAL CLOSED OFF LOW FRI AND SAT. AS A RESULT THE SURFACE TROUGH NOTED ABOVE WILL DRIFT INTO THE SOUTHERN GULF BY THU AND FRI AHEAD OF A COLD FRONT EXPECTED TO SLIP INTO THE NORTHERN GULF BY THU. THIS FRONT WILL SWEEP RAPIDLY SE AND EXTEND FROM TAMPA BAY TO THE BAY OF CAMPECHE DURING EARLY FRI AFTERNOON...AND MOVE SE OF GULF BY EARLY SAT AS WEAKENING FRONT WITH FRESH TO STRONG N TO NW WINDS IN ITS WAKE. DEPENDING ON THE ULTIMATE TRACK OF JOAQUIN WELL N OF THE AREA A SURGE OF MODERATE TO FRESH W TO NW WINDS ARE POSSIBLE OVER THE E GULF LATE SAT INTO SUN WITH SEAS POSSIBLY REACHING TO AROUND 5 FT THERE BEFORE SUBSIDING TO 3-4 FT LATE SUN AND MON. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... MODEL PREFERENCE: 12Z GFS BLENDED WITH PREVIOUS OFFICIAL. FOR WAVEHEIGHTS USED LATEST TAFB NWPS WAVE PARAMETERS. MEDIUM TO HIGH CONFIDENCE. CURRENT SHIP OBSERVATIONS AND NEWLY RECEIVED ASCAT DATA SHOW MAINLY GENTLE E-SE WINDS THROUGHOUT...WITH THE EXCEPTION OF THE S CENTRAL PORTION WHERE TRADES ARE MOSTLY 15 TO LOCALLY 20 KT THERE WITH SEAS OF 4-5 FT. SEAS ELSEWHERE ARE 2-3 FT...EXCEPT FOR 5-6 FT SEAS IN A NE SWELL IN THE TROPICAL N ATLC. THE SUBTROPICAL RIDGE THAT IS USUALLY N OF THE REGION RESPONSIBLE FOR MUCH OF THE STRONGER TRADE WIND FLOW HAS BEEN DISPLACED BY HURRICANE JOAQUIN LOCATED ABOUT 165 NM E OF THE CENTRAL BAHAMAS. THIS IS RESULTING IN WELL BELOW NORMAL TRADE WIND FLOW IN THE AREA. THIS TREND WILL CONTINUE AS THE RIDGE AXIS BRIEFLY BECOMES DISPLACED FARTHER S INTO THE NORTHERN CARIBBEAN THROUGH THE UPCOMING WEEKEND. ASIDE FROM LIGHT WINDS...ANOTHER UNUSUAL IMPACT OF THE MOVEMENT OF JOAQUIN NEAR THE BAHAMAS WILL BE ANOMALOUS SW TO W WINDS SPREADING OVER MUCH OF THE NW CARIBBEAN AND THE WINDWARD PASSAGE THROUGH EARLY ON SUN. DEPENDING ON THE TRACK AND INTENSITY OF JOAQUIN...THE SW FLOW MAY BE SLIGHTLY STRONGER THAN ANTICIPATED. THE 12Z UKMET/GFS MODEL GUIDANCE AGAIN DEPICTS SW WINDS TO 25 NEAR THE WINDWARD PASSAGE LATE THU AFTERNOON INTO FRI. THIS IS BEGINNING TO APPEAR MORE REALISTIC WITH TIME AS JOAQUIN EDGES TO THE SW. ...SW N ATLANTIC INCLUDING THE BAHAMAS... MODEL PREFERENCE: GLOBAL MODEL CONSENSUS AND OFFICIAL NHC FORECAST FOR JOAQUIN WINDS. USED LATEST TAFB NWPS WAVE PARAMETERS FOR WAVEHEIGHTS. MEDIUM CONFIDENCE. THE FORECAST FOR THE SW ATLC IS DEPENDENT UPON THE DEVELOPMENT AND MOVEMENT OF NOW STRENGTHENING HURRICANE JOAQUIN...CENTERED ABOUT 165 NM E OF THE CENTRAL BAHAMAS OR NEAR 24.4N 72.9W AS OF 2 PM THIS AFTERNOON. JOAQUIN IS FORECAST TO CONTINUE SLOWLY WSW THROUGH TONIGHT BEFORE IT TURNS TO THE NW AND DECREASES ITS FORWARD SPEED THU AND THU NIGHT. LONG PERIOD NE TO E SWELL REMAINS IN PLACE OVER MUCH OF THE REGION N OF 25N AND THE BAHAMAS...THE RESULT OF A LONG FETCH OF EASTERLY WINDS ALONG A FRONTAL BOUNDARY OVER THE CENTRAL ATLC. TAFB WAVEHEIGHT GRIDS WERE ADJUSTED UPWARD ABOUT 2-3 FT FAR WESTERN WATERS TO ACCOUNT FOR THE HIGH SEAS RESULTING IN THE NE-E SWELL AS REPORTED BY BUOY 41010 AND EARLIER ALTIMETER PASS NEAR THAT AREA. THE 1504 UTC ASCAT PASS NICELY DEPICTED PERIPHERAL 20-30 KT WINDS OVER THE W SEMICIRCLE OF JOAQUIN. WITH THE STRENGTHENING OF JOAQUIN OVER THE NEXT FEW DAYS...EXPECT LARGE SEAS IN SWELL TO CONTINUE TO RADIATE OUTWARD FROM JOAQUIN AFFECTING THE VAST MAJORITY OF THE BASIN. THE LATEST NHC ADVISORY VALID 15 UTC HAS JOAQUIN CONTINUING TO STRENGTHEN AS IT NEARS NEARS 25.3N 74.5W EARLY FRI MORNING AND TO NEAR 28.5N 73.5W EARLY SAT WITH MAXIMUM SUSTAINED WINDS 100 KT GUSTS 120 KT. FORECAST CONDITIONS AND TRACK IS SUBJECT TO CHANGE. STAY TUNED TO THE LATEST ADVISORY. AS THE STORM WARNING AND ITS EFFECTS SHIFT N OF THE AREA BY SUN...EXPECT GENTLE TO MODERATE SW TO W WINDS ACROSS THE REGION...EXCEPT RESIDUAL STRONG SW WINDS N OF 25N AND W OF 73W...SHIFTING TO N OF 27N W OF 73W MON WITH SEAS IN THE 6-8 FT RANGE. $$ .WARNINGS...ANY CHANGES IMPACTING COASTAL NWS OFFICES WILL BE COORDINATED THROUGH AWIPS 12 PLANET CHAT OR BY TELEPHONE: .GULF OF MEXICO... NONE. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... NONE. .SW N ATLANTIC INCLUDING THE BAHAMAS... .AMZ113...ATLANTIC FROM 27N TO 31N BETWEEN 70W AND 77W... TROPICAL STORM WARNING FRI. .AMZ117...BAHAMAS INCLUDING CAY SAL BANK... HURRICANE WARNING TONIGHT INTO FRI. .AMZ119...ATLANTIC FROM 22N TO 27N E OF BAHAMAS TO 70W... HURRICANE WARNING THIS AFTERNOON INTO FRI. $$ *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 AGUIRRE. NATIONAL HURRICANE CENTER.