000 AGXX40 KNHC 071855 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 255 PM EDT FRI AUG 7 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: GLOBAL MODEL CONSENSUS A BROAD AND WEAK RIDGE EXTENDS FROM SW FLORIDA SOMEWHAT W-NW TO W CENTRAL PORTIONS ALONG ABOUT 26.5N. OBS CONTINUE TO INDICATE ANTICYCLONIC FLOW PREVAILING AT 15 KT OR LESS...EXCEPT ACROSS NE PORTIONS WHERE THE WLY FLOW IS FRESHENING AHEAD OF A SINKING FRONTAL BOUNDARY ACROSS THE SE U.S....AND A SMALL AREA OF 15-20 KT SE WINDS ACROSS SW PORTIONS WHERE REMNANTS OF YUCATAN THERMAL TROUGH CONTINUE TO SHIFT W-NW. OFF NW CUBA. MAX SWH OBS AT 4 FT ACROSS SW PORTIONS AND ACROSS S TX COASTAL WATERS. LITTLE CHANGE IN RECENT FORECAST REASONING AS WEAK RIDGE WILL GENERALLY REMAIN IN PLACE WHILE DEEP LAYERED LOW CONTINUES TO DIG SE INTO SE U.S. WITH SFC LOW SHIFTING E-NE OFF MID ATLC COAST AND DRAGGING FRONTAL TROUGH INTO FL PANHANDLE SAT AFTERNOON WHERE IT WILL MEANDER THROUGH MON BEFORE BEGINNING TO LIFT N MON NIGHT-TUE. GFS BRIEFLY FORECASTS WLY WINDS NEAR 20 KT TONIGHT THROUGH SAT MORNING ACROSS NE COASTAL WATERS. MOISTURE AND MID TO UPPER DYNAMICS IN PLACE ACROSS NE PORTIONS TONIGHT THROUGH SUN EXPECTED TO YIELD ACTIVE WEATHER...LIKELY IN BANDS AND LINES. THE THERMAL TROUGH WILL DEVELOP EACH EVENING OVER THE YUCATAN PENINSULA AND MOVE NW DURING LATE NIGHT THROUGH EARLY MORNING HOURS BEFORE DISSIPATING OVER THE SW GULF DURING LATE MORNING HOURS. MODERATE TO FRESH WINDS AND SEAS OF 4-6 FT WILL BE ASSOCIATED WITH THIS TROUGH MAINLY IN THE LATE NIGHT AND EARLY MORNING HOURS. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... MODEL PREFERENCE: GFS-ECMWF CONSENSUS A 1017 MB HIGH NEAR 27N70W EXTENDS WEAK RIDGE W-SW ACROSS NW BAHAMAS TO SE FLORIDA AND IS EXPECTED TO COLLAPSE TONIGHT. INDUCED PRES GRADIENT HAS ALREADY BEGUN TO DIMINISH ACROSS THE BASIN WITH STRONG TRADES ACROSS S CENTRAL PORTIONS CONFINED TO S OF 13.5N THIS MORNING WITH PEAK WIND AND SEAS THEN 30 KT AND 11 FT OFF OF COLOMBIA. BUOY 42058 REFLECTS THIS TREND AND IS NOW 7 FT...DOWN 2-3 FT FROM 24 HOURS AGO. REMNANTS OF TROPICAL LOW MOVING ACROSS LESSER ANTILLES ATTM AND HAS OPENED UP TO A TROUGH. NO CHANGES IN GUIDANCE AND FORECAST REMAINS GENERALLY THE SAME. CENTRAL ATLC RIDGE TO SHIFT NE AND ASSOCIATED RIDGING ACROSS SW N ATLC TO WEAKEN THROUGH EARLY SAT AND CONTINUE TO WEAKEN PRES GRADIENT ACROSS THE BASIN...AND STRONG TRADES ACROSS S CENTRAL PORTIONS TO SHRINK SIGNIFICANTLY. BLOCKING OF LLVL RIDGE BY TUTT REFLECTION ALONG 62W ATTM TO LIFT OUT OF AREA LATE MON AND ALLOW ATLC RIDGE TO BEGIN TO BUILD INTO BAHAMAS BY TUE FOR MODEST FRESHENING OF TRADES ACROSS BASIN MON NIGHT THROUGH MID WEEK. ...SW N ATLANTIC INCLUDING THE BAHAMAS... MODEL PREFERENCE: GLOBAL MODEL CONSENSUS ATLC RIDGE CONTINUES TO BE SEPARATED BY TUTT LOW REFLECTION ACROSS W CENTRAL ATLC ALONG 62W...WITH 1017 MB HIGH NEAR 28N70W AND YIELDING LIGHT TO GENTLE FLOW ACROSS MOST OF AREA...EXCEPT FOR FRESHENING SWLY FLOW ACROSS NW PORTIONS IN ADVANCE OF SE U.S. FRONTAL SYSTEM. THIS WEAK HIGH TO COLLAPSE TONIGHT AND FRONTAL TROUGH WILL SINK S INTO EXTREME NW PORTIONS SAT MORNING...THEN SHIFT SLOWLY SSE THROUGH MON...WITH SWLY FLOW AROUND 20 KT PREVAILING ACROSS NW PORTIONS AHEAD OF BOUNDARY THROUGH LATE SAT. SEAS TO BUILD TO 6-8 FT IN THIS AREA THROUGH SAT EVENING BEFORE WINDS AND SEAS SHIFT NE OUT OF AREA SAT NIGHT. A FEW TROUGHS AND/OR CONVERGENCE LINES EXPECTED TO DEVELOP AHEAD OF THE FRONTAL TROUGH AND YIELD ACTIVE WEATHER DURING THIS TIME. THE RIDGE WILL BEGIN TO RE-ESTABLISH ACROSS THE AREA MON NIGHT THROUGH MID WEEK TO PRODUCE GENERALLY MODERATE SE TO S FLOW ACROSS MOST OF THE AREA... EXCEPT MODERATE ELY TRADES SE PORTIONS. $$ .WARNINGS...ANY CHANGES IMPACTING COASTAL NWS OFFICES WILL BE COORDINATED THROUGH AWIPS 12 PLANET CHAT OR BY TELEPHONE: .GULF OF MEXICO... NONE. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... NONE. .SW N ATLANTIC INCLUDING THE BAHAMAS... NONE. $$ *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 STRIPLING. NATIONAL HURRICANE CENTER.