000 AGXX40 KNHC 061853 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 250 PM EDT FRI APR 6 2012 MARINE WEATHER DISCUSSION FOR THE GULF OF MEXICO...CARIBBEAN SEA AND TROPICAL N ATLC S OF 19N W OF 55W...AND SOUTHWEST NORTH ATLC FROM 19N TO 31N W OF 55W. GULF OF MEXICO... HIGH PRES HAS SHIFTED TO WELL SE OF THE GULF OVER THE LOWER STRAITS OF FLORIDA AND NW CUBA. A SHORTWAVE TROUGH IS SWINGING ESE THROUGH THE NE GULF WITH ITS ASSOCIATED SURFACE COLD FRONT EXTENDING FROM NE FLORIDA SW TO 27N87W TO 27N91W AND NW TO JUST E OF CORPUS CHRISTI TEXAS. BOTH SATELLITE IMAGERY AND NWS RADAR DISPLAYS SHOW A LINE OF DEVELOPING SHOWERS AND TSTMS AHEAD OF THE FRONT ALONG WHAT HAS BECOME EVIDENT AS A PRE-FRONTAL TROUGH THAT EXTENDS FROM NAPLES TO 25N87W. THE TROUGH WILL MOVE E ACROSS THE REMAINDER OF THE GULF AND OVER S FLORIDA THIS AFTERNOON WHILE THE COLD FRONT QUICKLY REACHES A LINE FROM NAPLES FLORIDA TO NEAR 27N94W BY LATE THIS AFTERNOON...THEN PUSH INTO THE STRAITS OF FLORIDA AND TO YUCATAN CHANNEL AS A WEAKENING FRONT TONIGHT AND TO E OF THE AREA SAT. STRONG HIGH PRES WILL BUILD IN ACROSS THE AREA BEHIND THE FRONT USHERING IN COOLER AND DRIER AIR WILL MOVE INTO THE FAR NE GULF BEHIND FRONT TONIGHT ACCOMPANIED BY FRESH NE WINDS. A STRONG PRES GRADIENT ON THE SRN PERIPHERY OF THE RIDGE WILL INDUCE NE-E 20 KT ACROSS THE SRN PART OF THE GULF E OF ABOUT 89W AND STRAITS OF FLORIDA INTO LATE SUN BEFORE THE GRADIENT SLACKENS WITH WEAKENING HIGH PRES. SEAS SHOULD BUILD TO 8 OR 9 FT IN THE STRAITS OF FLORIDA THROUGH LATE SUN THEN SUBSIDE TO LOW RANGES INTO WED. ANOTHER COLD FRONT WILL BRUSH THE NE GULF MON AND TUE...BUT WINDS AND SEAS ARE EXPECTED TO LOW WITH THIS FRONT. HIGH PRES WILL THEN BUILD SEWD ACROSS MUCH OF THE NRN GULF WATERS LATE TUE AND WED. CARIBBEAN SEA AND TROPICAL ATLC S OF 19N W OF 55W... BOTH BUOY OBSERVATIONS REVEAL MOSTLY LIGHT TRADES ACROSS THE AREA. IN ADDITION...A RECENTLY RECEIVED ASCAT PASS SHOWED SIMILAR WINDS. SLIGHTLY HIGHER NE-E 15-20 KT WINDS ARE SEEN IN THE FAR SRN PORTION OF CENTRAL CARIBBEAN AND TROPICAL N ATLC WATERS. N SWELLS ARE SLOWLY DIMINISHING ACROSS THE NRN PORTION OF THE TROPICAL N ATLC AS BUOY 41044 AT 22N59W IS NOW DOWN TO COMBINED SEAS OF 6 FT. HOWEVER THE BACK EDGE OF THE SWELL TRAIN IS SLOW IN CLEARING THE SRN AND CENTRAL PORTIONS OF THOSE SAME WATERS WHERE BUOYS 41101 AT 15N56W AND BUOY 41040 AT 14.5N53W ARE SHOWING COMBINED SEAS OF 9-11 IN THE N SWELLS. THESE SEAS SHOULD LOWER TO 8 OR 9 FT TONIGHT. LITTLE OVERALL CHANGE IS EXPECTED WITH THESE TRADES IN THE CARIBBEAN...HOWEVER IN THE TROPICAL N ATLC NE-E WINDS ARE EXPECTED TO INCREASE TO 15-20 KT MON INTO WED ACROSS MOST OF THOSE WATERS AS CENTRAL ATLC HIGH PRES RIDGING BUILDS SOME TO THE SW. STRONG HIGH PRES FROM THE ERN GULF AND WRN ATLC IS FORECAST TO BUILD SWD TOWARDS THE NW CARIBBEAN BEGINNING LATE SAT THROUGH EARLY MON BRINGING WITH IT A SURGE OF FRESH NE FLOW TO THE LEE OF CUBA AND WINDWARD PASSAGE. THE HIGH PRES THEN WEAKENS THROUGH WED ALLOWING FOR THESE WINDS TO DIMINISH. AS WITH RESPECT TO SEAS...N SWELLS ARE SLOWLY DIMINISHING ACROSS THE NRN PORTION OF THE TROPICAL N ATLC AS BUOY 41044 AT 22N59W IS NOW DOWN TO COMBINED SEAS OF 6 FT. HOWEVER THE REMAINING BACK EDGE OF THE RECENT EXPANSIVE SWELL TRAIN IS SLOW IN CLEARING THE SRN AND CENTRAL PORTIONS OF THOSE SAME WATERS WHERE BUOYS 41101 AT 15N56W AND BUOY 41040 AT 14.5N53W ARE SHOWING COMBINED SEAS OF 9-11 IN THE N SWELLS. THESE SEAS SHOULD LOWER TO 8 OR 9 FT TONIGHT BEFORE DECAYING EVEN FURTHER INTO WED. SOUTHWEST N ATLC FROM 19N TO 31N W OF 55W... THE PRELIMINARY Y 18 UTC SURFACE ANALYSIS HAS A RATHER ROBUST COLD FRONT ATTRIBUTED TO A PRETTY POTENT DEEP LAYER TROUGH FOR THIS TIME OF YEAR EXTENDING FROM A 1002 MB GALE CENTER N OF THE AREA AT 33N75W SW TO INLAND MELBOURNE FLORIDA. SATELLITE IMAGERY SHOWS AN EXPANDING AREA OF SCATTERED SHOWERS AND TSTMS OUT AHEAD OF THE FRONT SPREADING AS FAR E AS 65W AND S TO 25N. A PRE-FRONTAL TROUGH IS S OF THE COLD FRONT...AS VIVIDLY SEEN ON NWS RADAR IMAGERY AND ON SATELLITE IMAGERY...EXTENDING FROM 26N75W TO ACROSS S FLORIDA EARLY THIS AFTERNOON. WEAK HIGH PRES IS ESE OF THE COLD FRONT. BOTH ASCAT AND BUOY REPORTS SHOW SW WINDS OF 20-25 KT AHEAD OF THE FRONT E TO 65W...WHILE BEHIND IT NW WINDS OF 20 KT ARE NOTED WITH WINDS BECOMING N-NE 20-25 KT JUST N OF THE FORECAST WATERS BEHIND THE FRONT. LATEST BUOY OBSERVATIONS AND A FEW SHIP REPORTS SHOW GENERALLY LIGHT TO MODERATE SE-S WINDS ELSEWHERE ...EXCEPT S-SW WINDS OF 15-20 KT N OF 27N E OF 65W AND SW WINDS OF 20 KT S OF THE PRE-FRONTAL TROUGH AND W OF THE BAHAMAS. THE RIDGE WILL CONTINUE TO SHIFT EWD TO E OF THE FORECAST AREA BY EARLY SAT AS THE FRONT REACHES A PSN FROM BERMUDA TO CENTRAL CUBA BY EARLY SAT...VERY MUCH LIKE PREVIOUS FORECAST THINKING. THE FRONT WILL THEN AS WEAKENING FRONT FROM 22N64W TO ERN CUBA BY EARLY SUN. NWP MODELS STILL SUGGEST THAT A LARGE SURGE OF FRESH TO STRONG NORTHERLY WINDS WILL FOLLOW THE FRONT THROUGH SUN. N-NE WINDS OF 25-30 KT ARE EXPECTED BEHIND THE FRONT N OF 28N TONIGHT AND INTO SAT MORNING WITH SEAS BUILDING POSSIBLY UP TO 13 OR 14 FT OVER THOSE WATERS BEHIND THE FRONT. WINDS AND SEAS THEN UNDERGO A DIMINISHING TREND OVER MUCH OF THE WRN AND CENTRAL ATLC WATERS LATER ON SAT AND INTO MON AS HIGH PRES BUILDS FROM W TO E OVER THE AREA. THE HIGH PRES THEN BEGINS TO SHIFT EWD LATE MON AS A COLD FRONT MOVES OFFSHORE THE SE U.S. THIS FRONT IS EXPECTED TO REACH FROM ALONG 31N77W TO CENTRAL FLORIDA TUE MORNING...AND FROM NEAR 31N72W TO S FLORIDA AS A WEAKENING COLD FRONT LATER TUE AND WED. SW WINDS OF 20 KT ARE FORECAST TO PRECEDE THIS NEXT FRONT...BUT SHOULD BE CONFINED TO N OF ABOUT 28N WITH NW WINDS OF A SIMILAR SPEED BEHIND IT AS INDICATED BY BOTH GFS AND ECMWF BOUNDARY LAYER WIND GUIDANCE FROM 12 UTC TODAY. NOTE... EFFECTIVE APR 3, 2012 AT 1800 UTC THE OFFSHORE WATERS FORECAST ZONES CHANGED FOR THE CARIBBEAN AND SW N ATLANTIC AND THE GULF OF MEXICO. ISSUANCE TIME FOR THE GULF OF MEXICO OFFSHORE WATERS FORECASTS IS REFERENCED TO THE EASTERN TIME ZONE. FOR DETAILS SEE WWW.NHC.NOAA.GOV/ABOUTTAFBPROD.SHTML#OWF GRIDDED MARINE OUTPUT IS AVAILABLE AT WWW.NHC.NOAA.GOV/TAFB/GRIDDED_MARINE (LOWER CASE). GULF OF MEXICO... .NONE. .CARIBBEAN SEA AND TROPICAL N ATLC... .NONE. .SW N ATLC... .NONE. 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