000 AGXX40 KNHC 131908 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 305 PM EDT WED JUN 13 2012 MARINE WEATHER DISCUSSION FOR THE GULF OF MEXICO...CARIBBEAN SEA AND TROPICAL N ATLC...AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W. GULF OF MEXICO... A 1017 MB HIGH IS CENTERED OVER THE CENTRAL PART OF THE GULF AT 27N88W...WHILE A WEAK TROUGH EXTENDS FROM NE FL SW TO NEAR 28N86W. BOTH OF THESE FEATURES ARE KEEPING A RATHER WEAK PRES PATTERN IN PLACE THROUGHOUT. LATEST AND CURRENT BUOY AND OIL PLATFORMS SHOW NW WINDS OF 10 KT NE OF THE HIGH... NE TO E WINDS OF 10 KT SE OF THE HIGH...SE TO S WINDS OF 5-10 KT NW OF THE HIGH...AND NE TO E WINDS OF 10-15 KT IN THE SW PART OF THE GULF. SEAS ARE IN THE GENERAL RANGE OF 2-3 FT. UPCOMING CHANGES WILL BE ATTRIBUTED TO A WEAK COLD FRONT THAT DROPS SWD ACROSS THE NE GULF AND N FL ON THU BEFORE SLOWING DOWN AND BECOMING STATIONARY FROM CENTRAL FL SW TO NEAR 28N87W BY THU EVENING. HIGH PRES WILL SURGE SWD IN BEHIND THIS FRONT INTO EARLY SUN INCREASING THE PRES GRADIENT IN THE NE PORTION WHICH SHOULD ALLOW FOR NE TO E WINDS OF 15-20 KT TO MATERIALIZE IN THE NE AND FAR N CENTRAL PORTIONS OF GULF BEGINNING FRI AND LASTING INTO EARLY SUN BEFORE THEY BEGIN TO DIMINISH PER MODEL CONSENSUS. SEAS SHOULD BUILD TO 3-5 FT IN THOSE PORTIONS OF THE GULF DURING THAT PERIOD THEN SUBSIDE LATE SUN. THE 12 UTC RUN OF THE GFS HINTS AGAIN THAT A WEAK LOW DEVELOPS ALONG THE FRONT IN THE NE PART OF THE GULF EARLY ON THU...AND MOVES IT TO THE NW GULF BY MON. THE OTHER MODELS...AND EVEN THE 00 UTC ECMWF FROM LAST NIGHT DO NOT SUGGEST THAT THIS FEATURE WILL FORM. ALTHOUGH CANNOT RULE OUT THE POSSIBLY OF A WEAK LOW FORMING ON THE TAIL END OF THE FRONT UNDER A SOMEWHAT PERTURBED UPPER LEVEL NW FLOW...WILL FOLLOW CONSENSUS AND NOT DEPICT THIS FEATURE ON THE MANUEL FORECAST PROGS AND ON THE TEXT FORECAST PACKAGE. CARIBBEAN SEA AND TROPICAL N ATLC W OF 55W... A TRPCL WAVE EXTENDS FROM JUST S OF CENTRAL CUBA S TO NEAR 15N78W EARLY THIS AFTERNOON MOVING W 10-15 KT. ANOTHER TRPCL WAVE OVER THE TROPICAL N ATLC IS E OF THE AREA APPROACHING 50W MOVING W AT 15-20 KT. BOTH BUOY AND ASCAT DATA FROM THIS MORNING AND EARLY AFTERNOON REVEALED MODERATE TO FRESH BREEZES ACROSS MUCH OF THE CARIBBEAN E OF THE TROPICAL WAVE ...AND LIGHT E-SE WINDS W OF THE WAVE. A WEAK 1009 MB LOW IS ANALYZED IN THE FAR SW CARIBBEAN AT 11N81W WHICH IS ALONG THE MONSOON TROUGH. THE LATEST MODELS AGAIN SHOW THE TROPICAL WAVE IN THE CARIBBEAN TO SLOW ITS WESTWARD IN RESPONSE TO THE TROUGH AND COLD FRONT THAT MOVE S OVER FL AND AND WRN ATLC TONIGHT THROUGH FRI. THE WAVE APPEARS TO HAVE ALREADY BEGUN TO SOME OF MORE NW TURN...BUT ITS RELATED ENERGY IS EXPECTED TO MOVE INLAND THE YUCATAN PENINSULA THU NIGHT AND FRI. THE MONSOON TROUGH EXTENDING INTO THE SW CARIBBEAN FROM THE E PACIFIC WILL GRADUALLY LIFT NORTHWARD FRI AND SAT WITH THE 1009 MB LOW MOVING TO A PSN NEAR 15N86W BY MON. THE DETERMINISTIC MODELS...FOR THE MOST PART SLOWLY TRACK THE LOW TO THE NW... THROUGH MON...EXCEPT THE GFS TAKES IT INLAND HONDURAS MON WHILE ITS ENSEMBLE FORECAST KEEPS IT OFFSHORE. BASED ON MODEL CONSENSUS...AND GFS ENSEMBLE WILL KEEP THE LOW JUST OFFSHORE THE NE COAST OF HONDURAS BY MON. THE HPC/NHC AFTERNOON CONFERENCE CALL AGREED ON SUCH A SCENARIO. RIGHT NOW IT DOES NOT APPEAR THE LOW WILL HAVE LARGE IMPACTS ON WINDS AND SEAS...BUT WILL HAVE TO CLOSELY MONITOR FUTURE MODEL TRENDS FOR ANY FORESEEABLE CHANGES IN ASSOCIATED WINDS AND SEAS COMPARED TO WHAT IS CURRENTLY BEING OBSERVED NOW IN THAT PORTION OF THE SEA. WILL KEEP A VERY CLOSE EYE ON SATELLITE IMAGERY AS WELL TO WATCH FOR ANY POSSIBLE ORGANIZATION OF THIS FEATURE. THE WAVE E OF THE TROPICAL ATLC WILL ENTER THOSE THU NIGHT... AND MOVE ACROSS THAT PART OF THE ATLC THROUGH LATE FRI NIGHT. SOUTHWEST NORTH ATLC S OF 31N W OF 55W... THE PRELIMINARY 18 UTC SURFACE MAP HAS A COLD FRONT EXTENDING FROM NEAR 31N51W TO 26N58W...AND A TROUGH FROM 27N75W SW ACROSS THE CENTRAL BAHAMAS AND TO CENTRAL CUBA. THE ASCAT PASS FROM 1518 UTC THIS MORNING CAPTURED THE WIND SHIFT FROM NE TO SE NICELY ACROSS THE TROUGH. A VERY SMALL LOW WAS EVIDENT BY THE ASCAT PASS AND ALSO ON VISIBLE SATELLITE IMAGERY TO BE ON THE SRN PORTION OF THE TROUGH AT 23N78W. SCATTERED TSTMS ARE WITHIN 240 NM E OF THE TROUGH. A COLD FRONT IS JUST NW OF THE REGION OVER THE SE U.S. MOVING SE. A PRE-FRONTAL TROUGH EXTENDS FROM N OF THE AREA AT 33N78W SW TO WEAK LOW FORMING AT 31N78W...AND THEN SW TO ACROSS NE FL AND INTO THE FAR NE GULF. THE LOW ATTENDANT WITH THE COLD FRONT IS CURRENTLY OFFSHORE THE MID-ATLC COAST. LATEST BUOY AND ASCAT DATA SHOW RELATIVELY LIGHT E TO SE WINDS ACROSS THE AREA E OF THE TROUGH ACROSS THE BAHAMAS AND LIGHT S TO SW WINDS OVER THE NW WATERS TO THE SE OF THE PRE-FRONTAL TROUGH. NE TO E WINDS OF 5-10 KT ARE W OF THE TROUGH THAT IS OVER THE BAHAMAS. SEAS ARE IN THE RANGE OF 2-4 FT EXCEPT 4-5 FT IN A NE SWELL OVER THE FAR N CENTRAL PORTION. THE LOW OFF THE MID-ATLC COAST WILL DROP SE TO S AS THE LOW AT 31N78W RIDES NEWD ALONG THE TROUGH THROUGH THU NIGHT. THE COLD FRONT WILL REACH A PSN FROM 31N75W TO 28N80W BY THU AFTERNOON ...AND FROM 31N73W TO NW BAHAMAS AS WEAKENING BY LATE THU NIGHT ...AND WEAKENING FURTHER FROM NEAR 28N65W TO NEAR 26N71W BY EARLY FRI FOLLOWING GFS/UKMET/ECMWF GUIDANCES EXCEPT MOSTLY GFS FOR DAYS 4 AND 5. DIFFERENCES ARISE IN THE FORECAST OF THE LOW ONCE IT BEGINS TO NEAR THE FAR NRN PORTION OF THE CENTRAL WATERS THU NIGHT. BASED ON LATEST AVAILABLE MODEL GUIDANCE ...IT APPEARS THAT THE RESIDUAL ENERGY FROM THE LOW AT 31N78W WILL BECOME ENTRAINED INTO THE LOW OFF THE MID-ATLC AS IT DROPS S TO NEAR 30N72W EARLY FRI...THEN BEGINS TO SLIDE MORE TO THE SE THROUGH FRI NIGHT TO NEAR 29N72W FRI NIGHT BEFORE IT BEGINS TO TAKE MORE OF A NE MOTION AS BOTH THE DETERMINISTIC MODELS AND ENSEMBLES FROM BOTH THE GFS AND ECMWF ARE AGREEMENT WITH THIS PROJECTION. THE GLOBAL MODELS...WITH THE EXCEPTION OF THE UKMET...ARE SUGGESTING THAT ONCE THE LOW THEN SPLITS INTO TWO LATE FRI NIGHT INTO SAT AS STRONG UPPER LEVEL JET STREAM ENERGY ASSOCIATED WITH A SHARPENING UPPER TROUGH PUNCHES S INTO THE NRN PORTION. THIS UPPER TROUGH THEN IS PROG BY THE GFS TO RETROGRADE W LATE SUN AND MON AMPLIFYING A RIDGE TO ITS E. THIS WILL ALLOW FOR WHATEVER LOW OR LOWS THAT MATERIALIZE TO TRANSITION INTO A WEAKER TROUGH FEATURE TO EXTEND FROM THE NE WATERS SW TO THE SE BAHAMAS AND ERN CUBA BY LATE MON. THE IMPACTS FROM THESE FEATURES WILL BE SEEN MORE IN THEN SHORT TO MEDIUM RANGES OF THE FORECAST AS STRONG HIGH PRES FROM THE U.S. E COAST BRIDGES SWD BEHIND THE COLD FRONT BEGINNING LATE THU NIGHT AND INTO SUN CAUSING A TIGHT PRES GRADIENT EXPECTED TO LEAD TO NE WINDS OF 20 KT OVER THE FAR NW AND NRN PORTIONS FRI THU NIGHT INTO MOST OF SUN BEFORE THE GRADIENT WEAKENS LATER SUN AND MON WITH THE WEAKENING SURFACE LOW. EXPECT SEAS TO BUILD TO 8 OR 9 FT IN THESE WATERS SUN AND MON LATE FRI THROUGH SUN. NOTE...GRIDDED MARINE OUTPUT IS AVAILABLE AT WWW.NHC.NOAA.GOV/TAFB/GRIDDED_MARINE (LOWER CASE) GULF OF MEXICO... .NONE. CARIBBEAN SEA... .NONE. SW N ATLANTIC... .NONE. FOR ADDITIONAL INFORMATION PLEASE VISIT WWW.HURRICANES.GOV/MARINE $$ FORECASTER SCHAUER