000 AGXX40 KNHC 290525 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 125 AM EDT WED OCT 29 2014 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: LATEST GFS BLENDED WITH PREVIOUS OFFICIAL WHICH WAS A GFS/ECMWF BLEND. NWPS USED FOR WAVE PARAMETERS. MED-HIGH CONFIDENCE. A WEAK INVERTED TROUGH IS ANALYZED OVER THE N-CENTRAL GULF AS PREVIOUSLY FORECAST ACCOMPANIED BY ONLY A NE-E-SE 5-10 KT WIND SHIFT. THE TROUGH WILL SHIFT E TODAY TO OVER THE NE WATERS AND QUICKLY BE OVERTAKEN BY A WEAK COLD FRONT THAT WILL REACH FROM THE FL BIG BEND TO NEAR 25N86W AT SUNRISE ON THU. A STRONGER AND DRIER COLD FRONT WILL ARRIVE ACROSS THE N-CENTRAL AND NE GULF WATERS FRI NIGHT...AND CONTINUE SE OF THE GULF EARLY SAT NIGHT. THE GFS IS THE MOST AGGRESSIVE ON THE POST-FRONTAL NLY WINDS...AND BLENDING WITH ECMWF YIELDS N-NE 15-20 KT FLOW ACROSS THE ENTIRE GULF ON SAT...BECOMING E-SE 15 KT RETURN FLOW OVER THE NW WATERS ON SAT NIGHT. THE GRADIENT WILL TIGHTEN A LITTLE ON SUN WITH 15-20 KT E-SE RETURN FLOW FORECAST ACROSS THE ENTIRE GULF...EXCEPT THE DIURNAL NE 15-20 KT FLOW EXPECTED ALONG THE NW COAST OF THE YUCATAN PENINSULA ON BOTH SAT AND SUN EVENINGS. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... MODEL PREFERENCE: LATEST GFS BLENDED WITH PREVIOUS OFFICIAL WHICH WAS A GFS/ECMWF BLEND. NWPS USED FOR WAVE PARAMETERS. MEDIUM CONFIDENCE. THE VERY WEAK REMNANT LOW AND TROUGH FROM TS HANNA WILL MOVE W OVER BELIZE AND THE EASTERN COAST OF THE YUCATAN PENINSULA ELY TODAY WITH THE ASSOCIATED CONVECTION DENOTED IN TODAYS WEATHER GRIDS. A TROPICAL WAVE IS OVER THE E CARIBBEAN AND IS MOVING W IN PHASE WITH AN UPPER CYCLONE NOW FILLING OVER THE E CARIBBEAN AT 16N66W. SUBSIDENCE W OF THE CYCLONE CONTINUES TO SUPPRESS CONVECTION NEAR THE WAVE. EXPECT THE WAVE TO CONTINUE W PASSING THROUGH THE CENTRAL CARIBBEAN TONIGHT AND WED...AND LIKELY LOSE IDENTITY IN THE W CARIBBEAN ON FRI AS HAS THE PREVIOUS FEW TROPICAL WAVES. THE NORTHERN EXTENT OF THE WAVE PREVIOUSLY ANALYZED AS A TROUGH IS NOW ANALYZED AS AN ILL-DEFINED 1010 MB SURFACE LOW NEAR 19N62W THAT DOES HAS THE POSSIBILITY OF TROPICAL CYCLONE FORMATION OVER THE NEXT 5 DAYS. UPPER DIFFLUENCE E OF THE UPPER CYCLONE OVER THE NE CARIBBEAN IS ENHANCING CONSIDERABLE CONVECTION ACROSS THE ATLC WATERS NE OF THE LEEWARDS...WITH SMALL CLUSTERS OVER THE LEEWARDS AS WELL. THE WEAK LOW IS EXPECTED TO CONTINUE W-NW REACHING A POSITION JUST N OF PUERTO RICO EARLY TODAY WITH ONLY A NE-E-SE 5-10 KT WIND SHIFT EXPECTED TO OCCUR OVER THE CARIBBEAN TO THE N OF 18N AS THE LOW/TROUGH CONTINUES W AND PASSES THROUGH THE WINDWARD PASSAGE AREA ON FRI NIGHT. BY THEN A STRONG DRY COLD FRONT WILL BE MOVING INTO THE NW CARIBBEAN. THIS FRONT WILL REACH FROM THE WINDWARD PASSAGE TO NE NICARAGUA ON SAT NIGHT... AND FROM THE MONA PASSAGE TO NW COSTA RICA ON SUN NIGHT. NE 15-20 KT FLOW WILL BEGIN ACROSS THE NW CARIBBEAN ON SAT NIGHT... AND INCREASE TO 20 KT ACROSS THE ENTIRE CARIBBEAN W OF 68W ON SUN NIGHT WITH EMBEDDED PATCHES OF 25 KT. ...SW N ATLANTIC INCLUDING THE BAHAMAS... MODEL PREFERENCE: LATEST GFS BLENDED WITH PREVIOUS OFFICIAL WHICH WAS A GFS/ECMWF BLEND. NWPS USED FOR WAVE PARAMETERS. MEDIUM-HIGH CONFIDENCE. A SHEAR AXIS EXTENDS FROM 26N55W TO 24N65W TO N-CENTRAL HISPANIOLA. THE SHEAR AXIS IS EXPECTED TO WASH OUT TODAY. THE NORTHERN SEGMENT OF A TROPICAL WAVE IS ANALYZED AS AN ILL- DEFINED 1010 MB LOW PRES NEAR 19N62W WITHIN POSSIBLE TROPICAL CYCLONE FORMATION OVER THE NEXT 5 DAYS. UPPER DIFFLUENCE IS ENHANCING CONSIDERABLE CONVECTION ACROSS THE ATLC WATERS NE OF THE LEEWARDS WITHIN 180 NM OF 20N59W. THIS WEAK LOW IS EXPECTED TO CONTINUE W-NW REACHING A POSITION JUST N OF PUERTO RICO EARLY TODAY THEN OPEN INTO AN INVERTED TROUGH THAT WILL CONTINUE NW REACHING THE TURKS AND CAICOS AREA ON FRI NIGHT. IN THE MEAN TIME...EXPECT A BAND OF E-SE 20-25 KT WINDS TO ACCOMPANY A TROUGH EXTENDING NE FROM THE LOW THROUGH LATE TONIGHT. A NE-SW RIDGE TO NE FL COAST IS SHIFTING SE ATTM IN ADVANCE OF A WEAK COLD FRONT/TROUGH MOVING OFF THE SE GA COAST THIS AFTERNOON. A SECONDARY COLD FRONT/TROUGH WILL MOVE OFF THE SE GA COAST ON THU MORNING AND CONTINUE SLOWLY SE ACCOMPNAIED BY ONLY A 5-10 KT SW-W-NW WIND SHIFT. A STRONGER COLD FRONT PUSHES OFF THE SE GA COAST ON ON FRI INITIALLY ACCOMPANIED BY NW 15 KT WINDS WHICH WILL PUSH THE FRONT E MERGING WITH WHATEVER REMAINS OF ALL THE PREVIOUS BOUNDARIES...WITH A SINGLE FRONT EXTENDING FROM 31N72W TO TO E CUBA AT SUNRISE SAT. BUILDING HIGH PRESSURE WILL INCREASE THE NLY FLOW TO 20-30 KT BEHIND THE FRONT. NOTING THAT THE GFS IS AGAIN THE MOST AGGRESSIVE MODEL...AND HINTS AT A STRONG GALE ON SAT EVENING. THE OFFICIAL FORECAST USES A BLEND OF MUCH LESS AGGRESSIVE ECMWF AND WILL MOVE THE FRONT TO A PSN FROM 31N62W TO THE MONA PASSAGE AT SUNRISE ON SUN...WITH THE FRONT CONTINUING E ON SUN ACROSS THE WATERS N OF 25N...BUT QUICKLY BECOMING A SHEAR AXIS TO THE N OF PUERTO RICO. $$ .WARNINGS...ANY CHANGES IMPACTING COASTAL NWS OFFICES WILL BE COORDINATED THROUGH AWIPS 12 PLANET CHAT OR BY TELEPHONE: .GULF OF MEXICO... NONE. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... NONE. .SW N ATLANTIC INCLUDING THE BAHAMAS... NONE. $$ *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 NELSON. NATIONAL HURRICANE CENTER.