000 AGXX40 KNHC 211858 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 258 PM EDT FRI AUG 21 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 VERY WEAK RIDGE EXTENDING FROM NE GULF ACROSS CENTRAL FLORIDA PENINSULA TO CENTRAL BAHAMAS IS MAINTAINING A WEAK PRESSURE PATTERN OVER MUCH OF THE EASTERN GULF...WITH MODERATE SE RETURN FLOW ACROSS MUCH OF W HALF OF BASIN. MAIN WEATHER FEATURES ARE UPPER TROUGH INCHING INTO SE TEXAS AND TUTT LOW ACROSS YUCATAN SHIFTING W...WITH BOTH EXPECTED TO MAINTAIN UNSTABLE CONDITIONS TODAY. TEXAS TROUGH TO WEAKEN TONIGHT AND SAT WHILE TUTT LOW CONTINUES TO SHIFT W AND REMAIN ACTIVE. FARTHER SOUTH...THE TYPICAL YUCATAN LATE AFTERNOON-EVENING THERMAL TROUGH WILL DEVELOP EACH OF THE NEXT FEW DAYS. NO MAJOR DIFFERENCES IN MODEL GUIDANCE INDICATING A SLOW W-NW PROGRESSION OF THE SURFACE RIDGE ACROSS THE NORTHERN GULF THROUGH SUNDAY...THEN SHIFTING WNW TO ALONG TEXAS COAST MON-TUE. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... MODEL PREFERENCE: GFS-ECMWF CONSENSUS THE MAIN ISSUE IS THE TRACK OF HURRICANE DANNY..DUE TO ITS TINY SIZE. MODELS HAVE BEEN GRADUALLY COMING INTO BETTER AGREEMENT AND 15Z PACKAGE WAS VERY CLOSE TO A GFS-ECMWF CONSENSUS. WIND AND WAVE FIELD ARE MUCH SMALLER THAN TYPICAL ATLC SYSTEM...AND OUR GRIDS WERE OVERDONE IN SIZE OF THESE FIELDS OVERNIGHT...AND PROBABLY LONGER. HAVE ATTEMPTED TO WHITTLE DOWN BOTH. DANNY EXPECTED TO MOVE ACROSS N HALF OF TROPICAL N ATLC WATERS SUN AND ACROSS THE LEEWARDS MON MORNING THEN REACH NEAR SE COAST OF P.R. TUE MORNING. SWLY SHEAR ALREADY IMPINGING UPON DANNY AND IT HAS REACHED IT PEAK STRENGTH AND SHOULD BEGIN TO WEAKEN NEXT FEW DAYS. SEE LATEST DISCUSSION FOR LATEST THINKING. ELSEWHERE A TUTT LOW IS MOVING WEST ACROSS THE YUCATAN AND STILL CREATING UNSTABLE CONDITIONS NW PORTIONS. A TROPICAL WAVE ALONG ABOUT 79W WILL CONTINUE W ACROSS SW PORTIONS TONIGHT AND SAT AND SCRAPE THE GULF OF HONDURAS SUN AS IT SHIFTS WWD INTO THE EPAC. FRESH TO STRONG TRADES WILL BEGIN TO DIMINISH SUN AS DANNY APPROACHES NE CARIB...AND REMAIN FRESH THROUGH MID WEEK. NEXT TROPICAL WAVE TO FOLLOW DANNY IS COMPLEX AND COULD ACTUALLY BE ENERGY FROM 2 WAVES BY THE TIME IT REACHES THE TROPICAL N ATLC WATERS TUE. BROAD WIND SURGE AHEAD OF THIS FEATURE WILL SPREAD NELY WIND SWELL INTO THE REGIONAL WATERS MON-TUE FOR SEAS OF 7-9 FT. PREFERRED THE 00Z ECMWF WITH A STRONGER SOLUTION AND LESS WEAKENING OF THIS WAVE AS IT APPROACHED THE CARIB. ...SW N ATLANTIC INCLUDING THE BAHAMAS... MODEL PREFERENCE: GFS-ECMWF CONSENSUS SHARP AND VIGOROUS DEEP LAYERED LOW JUST N OF BERMUDA HAS CARVED OUT A LOW LEVEL TROUGH WITH EMDEDDED LOWS PAST 24-48 HOURS...WITH BROAD SURFACE LOW ACROSS NE PORTIONS CENTERED NEAR 29N64W. THIS HAS COMPLETELY INTERRUPTED RIDGING AND TRADES ACROSS SE PORTIONS...WITH GULF OF MEXICO RIDGE EXTENDING SE TO THE CENTRAL BAHAMAS. THE DEEP LAYERED LOW IS EXPECTED TO LIFT OUT OF THE AREA SUN-MON AND ALLOW STRONG RIDGING TO BUILD BACK SW FROM NE ATLC INTO S HALF OF BAHAMAS. REMNANTS OF DANNY WILL IMPACT THE GREATER ANTILLES TUE-WED...HOPEFULLY WITH MUCH NEEDED RAIN AND MODEST WIND. NARROW SWATH OF ESE SWELL FROM DANNY WILL MOVE INTO SE PORTIONS TUE AND WED...WITH NEXT LARGE TROPICAL WAVE AND BIG WIND FIELD TO SPREAD ELY TRADE WIND SWELL INTO THE SE WATERS BY MID WEEK. PREFER ECMWF SOLUTION DURING THE PERIOD...IN GENERAL. $$ .WARNINGS...ANY CHANGES IMPACTING COASTAL NWS OFFICES WILL BE COORDINATED THROUGH AWIPS 12 PLANET CHAT OR BY TELEPHONE: .GULF OF MEXICO... NONE. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... .AMZ025...OFFSHORE WATERS LEEWARD ISLANDS... TROPICAL STORM WARNING SUN NIGHT INTO MON NIGHT. .AMZ027...TROPICAL N ATLANTIC FROM 15N TO 19N BETWEEN 55W AND 60W... HURRICANE WARNING SAT NIGHT. TROPICAL STORM WARNING SUN INTO SUN NIGHT. .SW N ATLANTIC INCLUDING THE BAHAMAS... .AMZ125...ATLANTIC S OF 22N BETWEEN 65W AND 70W INCLUDING PUERTO RICO TRENCH... TROPICAL STORM WARNING TUE NIGHT. $$ *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.