000 AGXX40 KNHC 210800 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 400 AM 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: 00Z GFS BLENDED WITH PREVIOUS FORECAST. HIGH CONFIDENCE. 1017 MB SURFACE HIGH PRES OVER N CENTRAL FLORIDA PENINSULA IS MAINTAINING A WEAK PRESSURE PATTERN OVER MUCH OF THE EASTERN GULF. ASCAT DATA FROM 04 UTC SHOWS A TROUGH OFF THE COAST OF TAMAULIPAS IN THE FAR WESTERN GULF SUPPORTING 15 TO 20 KT SE WINDS. CONVERGENCE OF THIS FLOW IS SUPPORTING SCATTERED THUNDERSTORMS OFF S TEXAS CURRENTLY. FARTHER SOUTH...THE STANDARD OVERNIGHT TROUGH IS NOTED ALONG THE WEST COAST OF THE YUCATAN PENINSULA. NO MAJOR DIFFERENCES IN MODEL GUIDANCE INDICATING A SLOW WESTWARD PROGRESSION OF THE SURFACE RIDGE ACROSS THE NORTHERN GULF THROUGH SUNDAY WITH THE CONTINUED NIGHTLY OCCURRENCE OF THE SURFACE TROUGH OVER THE NW YUCATAN. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... MODEL PREFERENCE: 00Z GFS BLENDED WITH PREVIOUS FORECAST. HIGH CONFIDENCE. THE MAIN ISSUE IS THE DEVELOPMENT AND TRACK OF HURRICANE DANNY IN THE ATLC ABOUT 1000 NM EAST OF THE LEEWARD ISLANDS MOVING WEST AND EXPECTED WEAKEN TO A TROPICAL STORM AS IT NEARS THE LEEWARDS MON. IT IS EXPECTED TO REMAIN A VERY SMALL CYCLONE WITH A TIGHT PRESSURE GRADIENT AND A SMALL AREA OF HIGH WINDS AND LARGE SEAS. UNCERTAINTY IN THE FORECAST IS DIRECTLY RELATED TO THE TRACK AND INTENSITY OF HURRICANE WARNING DANNY. REFER TO THE LATEST FORECASTS ISSUED BY THE NATIONAL HURRICANE CENTER FOR THE MOST UP TO DATE DETAILS...INCLUDING THE FORECAST DISCUSSION AND THE OFFICIAL PROG REASONING. ELSEWHERE AN UPPER LOW IS MOVING WEST ACROSS THE GULF OF HONDURAS...SUPPORTING AN AREA OF SHOWERS AN THUNDERSTORMS FROM THE CENTRAL COAST OF HONDURAS TO THE YUCATAN CHANNEL. THIS WILL END LATER THIS MORNING AS THE LOW SHIFTS WEST. A TROPICAL WAVE BETWEEN THE MONA PASSAGE TO CURACAO WILL SHIFT WEST INTO THE SW CARIBBEAN THROUGH EARLY NEXT WEEK. FRESH TO OCCASIONALLY STRONG TRADES WILL PERSIST OFF THE COAST OF COLOMBIA AND WESTERN VENEZUELA...INCREASING SLIGHTLY SAT IN THE WAKE OF THE TROPICAL WAVE. ...SW N ATLANTIC INCLUDING THE BAHAMAS... MODEL PREFERENCE: 00Z GFS BLENDED WITH PREVIOUS FORECAST. LOW TO MEDIUM CONFIDENCE. A BROAD AREA OF LOW PRES CONTINUES TO SHIFT EASTWARD NEAR 29N65W TO THE SOUTH OF BERMUDA. THE LOW WILL DEEPEN SLIGHTLY AS IT DRIFTS N OF THE AREA THROUGH SAT. MEANWHILE...A TROUGH WILL EXTEND SW FROM THE DEPARTING TO THE CENTRAL BAHAMAS. HURRICANE DANNY IS EXPECTED TO PASS CLOSE TO THE VIRGIN ISLANDS AND PUERTO RICO EARLY NEXT WEEK AS A SMALL TROPICAL CYCLONE...THEN MOVE W-NW N OF HISPANIOLA AND CUBA TOWARD THE SOUTHERN BAHAMAS. ITS INTENSITY AT THAT POINT IS UNCERTAIN. GFS AND EUROPEAN MODEL GUIDANCE HAVE BEEN CONSISTENT WITH THE TRACK FORECAST OVER THE PAST SEVERAL MODEL RUNS...BUT THEIR INTENSITY OF THE CYCLONE HAS NOT. BOTH MODELS WEAKEN DANNY TO EITHER A LOW OR A STRONG TROUGH. THIS MAY BE RELATED TO SMALL SIZE OF THE SYSTEM. LARGE UNCERTAINTY IN THE FORECAST IS RELATED TO WHAT HAPPENS TO DANNY. REFER TO LATEST FORECAST ISSUED BY THE NATIONAL HURRICANE CENTER FOR DETAILS...INCLUDING THE FORECAST DISCUSSION AND THE OFFICIAL PROG REASONING. $$ .WARNINGS...ANY CHANGES IMPACTING COASTAL NWS OFFICES WILL BE COORDINATED THROUGH AWIPS 12 PLANET CHAT OR BY TELEPHONE: .GULF OF MEXICO... NONE. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... NONE. .SW N ATLANTIC INCLUDING THE BAHAMAS... NONE. $$ *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 CHRISTENSEN. NATIONAL HURRICANE CENTER.