000 AGXX40 KNHC 071842 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 245 PM EDT SAT JUL 07 2012 MARINE WEATHER DISCUSSION FOR THE GULF OF MEXICO...CARIBBEAN SEA AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W. ................................................................. ATTENTION - SATELLITE TRANSMISSION OF NATIONAL WEATHER SERVICE HIGH SEAS FORECASTS HAS BEEN TEMPORARILY DISRUPTED. PLEASE VISIT THE FOLLOWING WEBSITE FOR MARINE FORECASTS: WWW.HURRICANES.GOV/MARINE ................................................................. GULF OF MEXICO... AN E TO W RIDGE EXTENDS ACROSS THE NORTHERN GULF ALONG 28N WITH A 1019 MB SURFACE HIGH OVER THE NE WATERS. THE NORTHERN END OF A TROPICAL WAVE EXTENDS THROUGH THE STRAITS OF FLORIDA. AN UPPER CYCLONE IS NEAR 24N85W WHILE AN UPPER RIDGE EXTENDS FROM ITS EASTERN FLANK TO AN ANTICYCLONE CENTERED NEAR THE HONDURAS/NICARAGUA BORDER. UPPER DIFFLUENCE ALONG THE RIDGE AXIS HAS BEEN LIFTING THE LOW LEVEL MOISTURE POOLED NEAR THE WAVE AND ENHANCING CONVECTION OVER W CUBA AND THE FL STRAITS. EXPECT THIS WAVE TO CONTINUE W THROUGH THE YUCATAN CHANNEL BY TONIGHT AND MOVE INTO THE BAY OF CAMPECHE SUN MORNING. ENERGY ON THE N SIDE OF THE WAVE SHOULD LINGER OVER THE SW GULF AS THE TROPICAL WAVE CONTINUES INTO THE PACIFIC. A SURFACE TROUGH ASSOCIATED WITH THIS ENERGY IS FORECAST TO REMAIN OVER THE SW GULF THROUGH TUE. OTHERWISE...CONDITIONS ARE REASONABLY QUIET OVER THE GULF. MODEL DIFFERENCES COME INTO PLAY WITH THE AMPLITUDE OF THE DEEP LAYER TROUGH MOVING INTO THE CENTRAL GULF STATES ON THU. THE GFS SOLUTION IS IN LINE WITH THE MODEL CONSENSUS. THE OFFICIAL FORECAST BLENDS THE 12Z GFS WITH CONTINUITY THIS AFTERNOON THROUGH THU. SW N ATLC S OF 31N W OF 55W... A RIDGE EXTENDS E TO W ALONG 28N THIS AFTERNOON WITH GUIDANCE SUGGESTING THE RIDGE WILL MEANDER ALONG ROUGHLY THIS POSITION THROUGH MON BEFORE LIFTING N OF THE AREA. SW WINDS N OF THE RIDGE WILL CONTINUE AT 10-15 KT...WHILE ELY WINDS S OF 23N WILL BE MOSTLY IN THE 15-20 KT RANGE THROUGH THE PERIOD EXCEPT MOSTLY 20 KT ACROSS OFFSHORE ZONE AMZ123. 20 KT WINDS N OF HISPANIOLA THIS MORNING WERE BEST INITIALIZED BY THE STRONGER 12Z GFS COMPARED TO THE REMAINDER OF THE MODEL GUIDANCE. THE NORTH END OF THE TROPICAL WAVE THAT EXTENDS FROM THE NW CARIBBEAN INTO THE STRAITS OF FLORIDA IS BRINGING SCATTERED TSTMS TO THE WESTERN BAHAMAS AND THE FL KEYS. SOME ENERGY IS EXPECTED TO BE SHED FROM THE NORTHERN END OF THIS WAVE. THAT ENERGY SHOULD LINGER BETWEEN SE FL AND THE BAHAMAS THOUGH MON BEFORE SHIFTING ONSHORE INTO FL TUE. THIS LINGERING ENERGY ACCOMPANIED BY INCREASING PRECIPITABLE WATER VALUES SHOULD ALLOW THE CHANCE OF SCATTERED SHOWERS AND TSTMS TO CONTINUE HERE THROUGH TUE. ANOTHER TROPICAL WAVE WILL MOVE W TO ALONG 65W EARLY MON AND CONTINUE W THROUGH THE SOUTHERN BAHAMAS TUE AND WED. THIS WAVE APPEARS MUCH DRIER THAN THE WAVE THAT IS PASSING W OF THE AREA ATTM. HOWEVER... THIS NEXT WAVE WILL BE MOVING INTO A POOL OF 1.75 TO 2.00 INCH PRECIPITABLE WATER VALUES BY TUE AS IT APPROACHES THE BAHAMAS. IT IS EXPECTED TO BRING AN INCREASED CHANCE OF SCATTERED SHOWERS AND ISOLATED TSTMS TO THE BAHAMAS AND SOUTHERN FLORIDA TUE THROUGH THU. OVERALL...THE NUMERICAL GUIDANCE IS IN REASONABLY GOOD AGREEMENT. THE OFFICIAL FORECAST BLENDS THE 12Z GFS WITH CONTINUITY THIS AFTERNOON THROUGH THU. CARIBBEAN SEA AND TROPICAL N ATLC W OF 55W... THE TROPICAL WAVE FROM THE YUCATAN CHANNEL TO THE GULF OF HONDURAS WILL MOVE W OF AREA BY TONIGHT. ELY TRADES ARE AT MOSTLY 25-30 KT ACROSS THE S CENTRAL CARIBBEAN WITH 20-25 KT OBSERVED ACROSS THE CARIBBEAN ELSEWHERE BETWEEN 68W AND 82W. SHIP VRFW5 REPORTED 30 KT NEAR 11.5N74W AT 12Z WHILE BUOY 42058 HAS REPORTED BETWEEN 10-11 FT BETWEEN 12Z-18Z. THE 12Z GFS MATCHES THESE CONDITIONS WELL. GUIDANCE INDICATES THAT THE GRADIENT WILL RELAX SOME SUN THROUGH MON...THEN THE GRADIENT TIGHTENS AGAIN TUE AND WED BEHIND THE TROPICAL WAVE PASSING THROUGH THE GREATER ANTILLES. THE STRONGER 12Z GFS SOLUTION WAS DOING BETTER THAN THE 00Z ECMWF AND OTHER 12Z GLOBAL MODELS THIS MORNING...SO THE OFFICIAL FORECAST BLENDS THE 12Z GFS WITH CONTINUITY THIS AFTERNOON THROUGH THU. NOTE...GRIDDED MARINE OUTPUT IS AVAILABLE AT WWW.NHC.NOAA.GOV/TAFB/GRIDDED_MARINE GULF OF MEXICO... .NONE. CARIBBEAN SEA... .NONE. SW N ATLANTIC... .NONE. FOR ADDITIONAL INFORMATION PLEASE VISIT WWW.HURRICANES.GOV/MARINE $$ FORECASTER SCHAUER