000 AGXX40 KNHC 130728 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 328 AM EDT THU AUG 13 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: 00Z GFS BLENDED WITH PREVIOUS OFFICIAL FORECAST FOR WINDS. FOR WAVEHEIGHTS BLENDED 00Z MWW3 WITH PREVIOUS OFFICIAL FORECAST. HIGH CONFIDENCE. WEAK HIGH PRES REMAINS ACROSS THE GULF ANCHORED BY A 1016 MB HIGH CENTERED 24N90W. A STATIONARY FRONT IS JUST INLAND THE NORTHERN GULF COAST. CURRENT BUOY OBSERVATIONS SHOW GENTLE E-SE WINDS W OF 93W...EXCEPT FOR A SMALL PATCH OF MODERATE E-SE WINDS IN THE EASTERN BAY OF CAMPECHE. E OF 93W...THE OBSERVATIONS SHOW SE-S GENTLE WINDS S OF 26N...AND GENTLE W-N WINDS N OF 26N. THE OBSERVATIONS ALONG WITH RECENT ALTIMETER PASSES ACROSS THE AREA SHOW LOW SEAS IN THE RANGE OF 1-2 FT THROUGHOUT. THE FRONT WILL SHIFT SLIGHTLY S TODAY AND TONIGHT. ONE OR TWO WEAK LOWS WILL DEVELOP ALONG THE FRONT ON FRI AND DRIFT WESTWARD ON SAT...BUT WILL HAVE NO IMPACTS ON WINDS OVER THE FORECAST WATERS. THE FRONT WILL GRADUALLY DISSIPATE THROUGH LATE SAT. LITTLE CHANGE IS EXPECTED WITH SEAS AND WINDS THROUGH THE PERIOD. SHOWER AND TSTM ACTIVITY WILL MOST ACTIVE DURING THE DAY ACROSS THE N CENTRAL AND NE PORTIONS THROUGH THE FORECAST PERIOD. A THERMAL TROUGH WILL DEVELOP EACH NIGHT ACROSS THE YUCATAN PENINSULA AND MOVE WNW DURING LATE NIGHT AND EARLY MORNING HOURS. THE TROUGH WILL GRADUALLY DISSIPATE ACROSS THE SW GULF DURING THE LATE MORNING HOURS. A BRIEF INSTANCE OF MODERATE E WINDS MAY OCCUR OVER THE EASTERN PORTION OF THE EASTERN BAY OF CAMPECHE. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... MODEL PREFERENCE: 00Z GFS BLENDED WITH PREVIOUS OFFICIAL FORECAST FOR WINDS. FOR WAVEHEIGHTS BLENDED 00Z MWW3 WITH PREVIOUS OFFICIAL FORECAST. HIGH CONFIDENCE. THE RESULTANT PRES GRADIENT BETWEEN SW ATLC RIDGING SITUATED OVER THE FAR SOUTHERN PORTION OF THE SW N ATLC AND LOWER PRES OVER THE WESTERN AND CENTRAL CARIBBEAN IS SUFFICIENT TO SUPPORT MODERATE TO FRESH TRADES ACROSS THE MUCH OF THE CENTRAL PORTION OF THE CARIBBEAN. A SMALL POCKET OF STRONG NE WINDS IS EXPECTED WITHIN AN AREA FROM 11N-13N BETWEEN 74W-76W DURING THE OVERNIGHT HOURS ...THEN AGAIN LATE TONIGHT INTO EARLY ON FRI...AND ON FRI NIGHT WITH A POSSIBILITY OF A BRIEF INSTANCE ON SAT NIGHT. THESE WINDS ARE FORECAST TO INDUCE SEAS OF 8-10 FT. SEAS ELSEWHERE ARE 5-8 FT S OF 17N BETWEEN 70W-81W...AND 4-6 FT OVER THE REMAINDER OF THE CARIBBEAN AND TROPICAL N ATLC...WITH THE EXCEPTION OF LOWER SEAS OF 2-4 FT W OF W OF 81W. THE MODERATE TO FRESH TRADES WILL EXPAND IN COVERAGE LATE FRI NIGHT INTO SAT...DIMINISH BRIEFLY SAT AFTERNOON AND EXPAND WESTWARD ON SUN TO NEAR 81W...AND TO 82W ON MON WITH SEAS IN THE 6-9 FT RANGE. A TROPICAL WAVE ALONG 79W S OF 20N IS MOVING W AT 15-20 KT. THE WAVE WILL MOVE W OF THE CARIBBEAN AND INLAND CENTRAL AMERICA ON FRI. A WEAK TROUGH FOLLOWING IN BEHIND THE WAVE IS ALONG 71W FROM 14N-18N. WEAKENING ISOLATED SHOWERS AND TSTMS ARE WITHIN 60 NM E OF THE TROUGH. THE TROUGH WILL REACH NEAR 78W...TO NEAR 80W FRI NIGHT AND DISSIPATE SAT. A TROPICAL WAVE ALONG 51W S OF 18N IS MOVING W AT 10-15 KT. THIS WAVE WILL MOVE INTO THE EASTERN PORTIONS OF ZONES AMZ027 AND AMZ037 THIS EVENING...AND ACROSS THE REMAINDER OF THOSE ZONES THROUGH FRI EVENING. THE WAVE WILL MOVE ACROSS THE LESSER ANTILLES AND FAR EASTERN CARIBBEAN FRI EVENING INTO EARLY SAT...AND ACROSS THE REST OF THE EASTERN CARIBBEAN DURING REMAINDER OF SAT AND THROUGH SUN. THE WAVE WILL THEN MOVE ACROSS THE EASTERN SECTION OF THE CENTRAL CARIBBEAN ON MON. THE GFS 10M WIND GUIDANCE INDICATES MAINLY 15 KT WINDS SHIFTING FROM NE TO SE ACROSS THE WAVE AXIS AS THE WAVE ENTERS THE EASTERN CARIBBEAN. THE 00Z ECMWF AND UKMET ARE IN GOOD AGREEMENT WITH THE GFS IN DEPICTING THE WIND SHIFT...AND WITH THE INTENSITY OF THESE WINDS. NE-E 15-20 KT TRADES S OF 16N IN THE EASTERN CARIBBEAN WILL INCREASE SOME IN COVERAGE SAT AND SAT NIGHT AS THE WAVE APPROACHES 70W. THESE WINDS WILL GRADUALLY DIMINISH IN COVERAGE MON. ...SW N ATLANTIC INCLUDING THE BAHAMAS... MODEL PREFERENCE: 00Z GFS BLENDED WITH PREVIOUS OFFICIAL FORECAST FOR WINDS. 00Z MWW3 BLENDED WITH PREVIOUS OFFICIAL FORECAST FOR WAVE HEIGHTS. HIGH CONFIDENCE. THE MAIN FEATURE ACROSS THE BASIN CONTINUES TO BE A WEAK RIDGE THAT STRETCHES FROM NEAR 31N65W SW TO THE FLORIDA KEYS. A RATHER ROBUST MID/UPPER TROUGH OVER THE EASTERN U.S. IS APPROACHING THE FAR NW CORNER OF THE AREA. THE TROUGH IS HELPING TO TRIGGER LARGE CLUSTERS OF TSTMS ALONG AND NEAR A STATIONARY FRONT THAT EXTENDS FROM 31N80W SW TO ALONG THE GEORGIA/NE FLORIDA BORDER. LIGHTNING DENSITY DATA IS SHOWING A HIGH FREQUENCY OF LIGHTNING STRIKES WITH THIS TSTM ACTIVITY...WHICH MOST LIKELY CONTAINS GUSTY WINDS AS WELL. BUOY OBSERVATIONS AND RECENT SCATTEROMETER DATA SHOW MOSTLY GENTLE TO OCCASIONAL MODERATE WINDS THROUGHOUT THE BASIN. WAVEHEIGHTS REMAIN IN THE 3-4 FT RANGE...WITH LOWER HEIGHTS OF 1-2 FT W OF THE BAHAMAS AND N OF THE BAHAMAS W OF 78W. THE RIDGE WILL REMAIN IN PLACE TODAY...THEN SLOWLY SLIDE NWD TO NEAR 28N ON FRI...AND TO JUST N OF THE AREA ON SAT. THE STATIONARY FRONT WILL SLIDE SWD SOME TODAY AND TONIGHT ...THEN LIFT BACK N SAT AND SAT NIGHT TO JUST NW OF THE AREA WHILE DISSIPATING. GFS MOISTURE CONVERGENCE GUIDANCE AND PRECIPITATION POTENTIAL SUGGEST THAT THE SCATTERED TSTM ACTIVITY WILL REMAIN QUITE ACTIVE OVER THE NW WATERS THROUGH LATE SAT. ELSEWHERE...NE TO E WINDS OF 20-25 KT BETWEEN THE SE BAHAMAS AND HISPANIOLA WILL DIMINISH TO 15-20 KT BY EARLY THIS AFTERNOON ...THEN PULSE BACK UP TO 20-25 KT EACH NIGHT THROUGH MON NIGHT WITH RELATED SEAS IN THE RANGE OF 5-6 FT. $$ .WARNINGS...ANY CHANGES IMPACTING COASTAL NWS OFFICES WILL BE COORDINATED THROUGH AWIPS 12 PLANET CHAT OR BY TELEPHONE: .GULF OF MEXICO... NONE. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... NONE. .SW N ATLANTIC INCLUDING THE BAHAMAS... NONE. $$ *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 AGUIRRE. NATIONAL HURRICANE CENTER.