000 AGXX40 KNHC 151941 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 240 PM EST SAT DEC 15 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... THE LATEST SURFACE ANALYSIS SHOWS A HIGH PRES RIDGE EXTENDING FROM THE MID-ATLC REGION OF THE U.S SOUTHWESTWARD TO ACROSS THE EASTERN AND CENTRAL GULF OF MEXICO. LOW PRES IS ANALYZED OVER FAR NE MEXICO AND SE TEXAS...WHILE A COLD FRONT STRETCHES FROM VERY DEEP LOW PRES OVER THE MID-WEST S TO S CENTRAL TEXAS. CURRENT BUOY AND PLATFORM OBSERVATIONS REVEAL E-SE WINDS OF 10-15 KT IN THE EASTERN PART OF THE GULF...SE-SE 10-15 KT WINDS IN THE CENTRAL PORTION AND HIGHER WINDS FROM THE SE-S AT 15-20 KT IN THE WESTERN PORTION. THE LATEST AND CURRENT OBSERVATIONS ARE REPORTING LOW SEAS OF 2-3 FT IN THE EASTERN PORTION EXCEPT 3-5 FT IN THE FAR SE WATERS AND STRAITS OF FLORIDA...2-4 FT IN THE CENTRAL PORTION AND 4-7 FT IN THE WESTERN PORTION WITH THE HIGHEST OF THESE SEAS FROM 25N TO 28N W OF 94W AS BUOY 42020 AT 27N97W AND 42019 AT 28N95.5W HAVE COMBINED SEAS OF 7 FT. LATEST NWS RADAR ANIMATIONS SHOW ISOLATED SHOWERS AND TSTMS IN THE MOIST SLY FLOW TO BE CONFINED OVER SECTIONS OF THE MIDDLE AND WESTERN GULF WATERS. A PROGRESSIVE PATTERN IS TAKING SHAPE ACROSS THE SE REGION OF THE U.S. AND GULF OF MEXICO DOMAIN. WILL KEEP TREND OF PREVIOUS FORECAST THINKING AS MODELS ARE RATHER CONSISTENT WITH NEAR FUTURE SCENARIO WITH RESPECT TO FORECAST CHANGES. THE RIDGE WILL MOVE E OF THE GULF SUN NIGHT ALLOWING FOR WINDS TO BECOME SOUTHERLY THROUGHOUT IN RESPONSE TO A COLD FRONT THAT MOVES OFF THE TEXAS SUN NIGHT. THE COLD FRONT WILL REACH FROM NEAR SE LOUISIANA TO THE SW GULF OF MEXICO EARLY MON...FROM NEAR TAMPA SW TO 25N88W TO EASTERN BAY OF CAMPECHE EARLY TUE...AND TO SE OF AREA LATE TUE. IN ITS WAKE...WEAK HIGH PRES WILL QUICKLY MOVE E ACROSS THE NRN WATERS TUE AND TO FAR NE GULF AND NE FLORIDA AREA TUE NIGHT AND WED...TO THE FAR WRN ATLC E OF NE FL BY LATE WED. SLY FLOW WILL DEVELOP JUST ABOUT ACROSS THE ENTIRE GULF WED AND THU IN ADVANCE OF YET ANOTHER COLD FRONT. THE FLOW WILL SIGNIFICANTLY INCREASE OVER THE FAR WRN WRN WATER WED NIGHT... THEN DIMINISH EARLY WITH THE APPROACH OF THE COLD FRONT. SEAS WILL CHANGE LITTLE IN THE EASTERN AND CENTRAL GULF THROUGH THE PERIOD. THE SEAS OF 3-5 FT IN THE FAR SE WATERS AND STRAITS OF FLORIDA WILL SUBSIDE TO 2-3 FT MON. THE 4-7 FT SEAS IN THE FAR WRN GULF SUBSIDE TO 3-5 FT TONIGHT...AND TO 2-4 FT MON THEN BEGIN TO BUILD AGAIN TO 5-7 FT WED AND THU IN THE INCREASING SLY FLOW. MODELS IN PRETTY AGREEMENT THAT THE FRONT WILL PUSH OFF THE TEXAS COAST THU MORNING FOLLOWED BY A STRONG PRES GRADIENT BRINGING N WINDS OF 20-30 KT ACROSS THE WESTERN AND CENTRAL GULF ZONES DURING THU. EXPECTED GALE CONDITIONS MAY BE A POSSIBILITY IN THE SW GULF ZONES BEGINS THE FRONT WHERE MODELS SUGGEST THE GRADIENT WILL BE THE TIGHTEST. WILL KEEP THIS MIND IN EVALUATING FUTURE MODEL RUNS. WITH RESPECT TO THE TIMING AND FORECAST OF THE FRONT AFTER IT EMERGES INTO THE GULF...THE 12 UTC GFS IS FASTER THAN THE 00 UTC ECMWF FROM LAST NIGHT IN PROGGING THE FRONT ACROSS THE GULF. HOWEVER...THE 12 UTC ECMWF HAS COME MORE IN LINE WITH THE 12 UTC GFS WITH THE FRONTAL POSITIONS IN TAKING IT TO A NE FLORIDA TO EASTERN BAY OF CAMPECHE LINE BY LATE THU. WILL FOLLOW THESE SOLNS FOR THIS FORECAST PACKAGE. FOR SEAS BEHIND THE FRONT...GRIDDED NWWIII BUILDS MAX SEAS TO 10 FT IN THE FAE W GULF TO 10 FT WHILE THE ECMWF WAVES BUILDS THEM TO 14 FT. ALTHOUGH THU WILL BE DAY 5...FOR NOW WILL LEAN TOWARDS THE 9 TO 12 FT RANGE AND UPDATE ACCORDINGLY TO FUTURE GUIDANCE MODEL RUNS. SW N ATLC S OF 31N W OF 65W... THE 18 UTC PRELIMINARY ANALYSIS HAS A COLD FRONT E OF THE AREA EXTENDING SW TO 25N65W WHERE IT BEGINS TO DISSIPATE TO THE CENTRAL BAHAMAS. THE ANALYSIS SHOWS HIGH PRES ELSEWHERE ACROSS THE BASIN. LATEST BUOY OBSERVATIONS ALONG WITH A SEVERAL SHIP REPORTS NOTE N-E WINDS OF 10-15 KT TO THE W OF THE FRONT EXCEPT FOR N-NE WINDS OF 15-20 KT N OF 27N E OF ABOUT 69W. THE OBSERVATIONS REVEAL SEAS OF 6-9 FT IN NE SWELLS BETWEEN THE FRONT AND THE BAHAMAS...AND 4-6 FT ELSEWHERE EXCEPT 3-5 FT SW OF THE BAHAMAS. WIDELY SCATTERED SHOWERS ARE WITHIN 60 NM OF THE FRONT. A MID/UPPER LEVEL TROUGH ACROSS THE E AND SE PORTIONS OF THE BASIN THAT SUPPORTS THE COLD FRONT JUST E OF THE AREA WILL SHIFT E OF THE AREA SUN AS HIGH PRES IN THE UPPER LEVEL OVER THE WRN PORTION MOVES E WITH THE ASSOCIATED SURFACE HIGH PRES MENTIONED ABOVE. MODELS IN GOOD AGREEMENT THAT THE HIGH PRES WILL CONTINUE TO SHIFT EWD TO E OF THE FORECAST ZONES ON TUE.THIS WILL ALLOW FOR A STRONGER COLD FRONT TO MOVE OFF THE SE U.S. AND NE FLORIDA COAST MON NIGHT INTO EARLY TUE. THE FRONT WILL REACH FROM NEAR 31N72W TO WESTERN CUBA BY EARLY TUE EVENING...AND TO OVER THE FAR SE WATERS BY LATE WED WHERE THAT PORTION OF THE FRONT DISSIPATES INTO THU. THE FRONT WILL BE PRECEDED BY INCREASING SW WINDS OF 20-25 KT PER GFS/ECMWF GUIDANCE...AND FOLLOWED BY NW WINDS OF 20-25 KT. SEAS ARE FORECAST TO BUILD TO AROUND 6-9 FT AHEAD OF THE FRONT...AND TO 8-14 FT IN A NW SWELL BEHIND IT PER A BLEND OF THE GRIDDED NWWIII AND ECMWF WAVE GUIDANCE. THE UKMET WAVE GUIDANCE ACTUALLY HAS SEAS UP TO 16 AND 17 FT IN THE FAR NE CORNER OF THE AREA LATE WED AND THU IN A NW SWELL. WILL KEEP THIS SOLN IN MIND AS IT MAY BE NEED TO BE INCORPORATED INTO THE FORECAST IN THE NEAR FUTURE PENDING THE PROGRESS OF THE DEVELOPING LARGE SEA STATE WELL N OF THE BASIN AS IT PROGRESSES SEWD DRIVEN IN NW SWELLS. HIGH PRES WILL THEN BUILD ACROSS THE ENTIRE AREA IN THE WAKE OF THE FRONT FOR DAYS 4 AND DAY 5. THE EXCEPTION WILL BE THE FAR NW WATERS THU WHERE SW WINDS BEGINS TO INCREASE ONCE AGAIN IN ADVANCE OF ANOTHER COLD MOVING THROUGH THE SE U.S. CARIBBEAN SEA AND TROPICAL N ATLC S OF 22N W OF 55W... THE ASCAT PASS FROM 1452 UTC THIS MORNING NICELY SHOWED THE NE TO SE WIND SHIFT WITH SURFACE TROUGH ROUGHLY NEAR 73W. THIS TROUGH IS MOVING W 15 KT THROUGH THE BASE OF THE MID/UPPER TROUGH LOCATED ACROSS THE NE CARIBBEAN. SATELLITE VIS IMAGERY SHOWS SCATTERED SHOWERS AND ISOLATED TSTMS ARE EVIDENT ALONG AND E OF THE TROUGH TO 66W. ELSEWHERE...A WEAK PRES GRADIENT CONTINUES AS WEAK ATLC HIGH REMAINS IN PLACE. THIS PATTERN SHOULD CONTINUE TO MAINTAIN GENTLE TO MODERATE TRADE WINDS INTO EARLY WED. THE TRADES INCREASE OVER MUCH OF THE CENTRAL CARIBBEAN BEGINNING LATER WED AND THROUGH THU AS STRONGER HIGH PRES BUILDS E ACROSS THE WESTERN ATLC. NE SWELLS PRODUCING COMBINED SEAS OF 7 FT OVER MUCH OF THE TROPICAL ATLC ARE EXPECTED TO SUBSIDE SUN AND SUN NIGHT AS NLY WINDS OVER THE NRN AND CENTRAL SECTIONS OF THOSE ZONES VEERS TO NE-E AND TO MORE OF AN E DIRECTION TUE THROUGH THU. THE SRN PORTION OF THE ABOVE MENTIONED COLD FRONT IS FORECAST TO GRAZE THE FAR NRN BOUNDARY OF THE TROPICAL N ATLC LATE WED AND THU...BUT SHOULD BE DISSIPATING AT THAT TIME WITH VERY LITTLE IMPACTS...IF ANY AT ALL...TO WINDS/SEAS OVER THE NRN PORTION OF THE TROPICAL N ATLC. NOTE...GRIDDED MARINE FORECAST IS AVAILABLE AT WWW.NHC.NOAA.GOV/TAFB/GRIDDED_MARINE GULF OF MEXICO... .NONE. CARIBBEAN SEA AND TROPICAL N ATLC... .NONE. SW N ATLANTIC... .NONE. 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