000 AGXX40 KNHC 181944 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 245 PM EST TUE DEC 18 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 THE COLD FRONT THAT MOVED OFF THE TEXAS YESTERDAY NOW EXTENDING FROM NE FLORIDA SW TO 25N89W TO 23N95W WHERE IT BECOMES STATIONARY TO THE CENTRAL BAY OF CAMPECHE. A WEAK TROUGH EXTENDS FROM 20N95W NNW TO 24N97W. WEAK 1018 MB HIGHS ARE AT 28N90W...AND INLAND MEXICO AT 22N98W. CURRENT BUOY AND PLATFORM OBSERVATIONS SHOW S-SW 15-20 KT WINDS OVER THE EASTERN AND CENTRAL GULF AHEAD OF THE FRONT...EXCEPT SE-S 10-15 KT WINDS S OF 25N E OF 89W. WINDS ARE S-SW 15-20 KT IN THE WRN GULF PORTION N OF 26N W OF 92W...AND N 10-15 KT ELSEWHERE IN RESPONSE TO PASSAGE OF THE FRONT. WAVE HEIGHT OBSERVATIONS SHOW SEAS IN THE RANGES FROM 2-3 FT OVER MOST OF THE GULF...EXCEPT FOR 3-4 FT IN THE NE PORTION. THE UPPER PATTERN HAS TRANSITIONED INTO AN EARLY WINTER APPEARING TYPE PROGRESSIVE ONE AS COMPARED TO THAT OBSERVED IN THE PREVIOUS DAYS. HIGH PRES OVER THE AREA HAS SHIFTED WELL E OF THE GULF TO THE ATLC. THE MID/UPPER TROUGH SUPPORTING THE SURFACE FRONTAL BOUNDARY IS QUICKLY MOVING E OVER THE FAR EASTERN GULF NOW EXTENDING FROM 23N93W NEWD TO ACROSS N CENTRAL FLORIDA AND N TO ALONG THE U.S. E COAST. FOR THIS FORECAST WILL FOLLOW CONTINUITY WITH PREVIOUS FORECAST REGARDING COLD FRONTS AS MODEL GUIDANCE HAS COME TO A GOOD AGREEMENT WITH TIMING/POSITIONS OF THE FRONTS. WITH THIS IN MIND WILL FORECAST CURRENT COLD FRONT BOUNDARY TO EXIT THE AREA EARLY TONIGHT. THE WEAK 1018 MB HIGH AT 28N90W WILL QUICKLY MOVE E TO THE FAR NE GULF TONIGHT...AND TO THE NW ATLC WED. SLY FLOW DEVELOPS JUST ABOUT ACROSS THE ENTIRE GULF WED AND THU IN ADVANCE OF YET ANOTHER COLD FRONT...STILL SUGGESTED BY THE MODELS TO BE STRONGER THAN RECENT ONES. THE SLY FLOW DIMINISHES WED NIGHT WITH THE APPROACH OF THIS NEXT COLD FRONT. SEAS WILL CHANGE LITTLE MOST ZONES THROUGH WED...HOWEVER WITH THE INCREASING SLY WINDS IN THE FAR WESTERN GULF...EXPECT SEAS THERE BUILD TO AROUND 7 OR 8 FT WED AND WED NIGHT. THE DETERMINISTIC MODELS AND EVEN THE GFS/ECMWF ENSEMBLES DEPICT THIS NEXT COLD FRONT EMERGING OFF THE TEXAS COAST LATE WED NIGHT INTO EARLY THU MORNING. THE FRONT WILL THEN RACE ACROSS THE GULF TO A POSITION FROM NEAR PENSACOLA FLORIDA TO 25N92W TO VERACRUZ MEXICO BY EARLY THU AFTERNOON...FROM NEAR THE FLORIDA KEYS TO NW YUCATAN PENINSULA EARLY FRI MORNING...AND TO SE OF THE GULF LATER DURING FRI MORNING. A COLD AND STRONG HIGH PRES AREA...THE FIRST OF THE UPCOMING EARLY WINTER SEASON...WILL BUILD E ACROSS THE AREA BEHIND THE FRONT BRINGING STRONG TO GALE FORCE N WINDS OVER MUCH OF THE WESTERN GULF IN A STRONG PRES GRADIENT. WILL A STRONG PRES GRADIENT DEVELOPING BETWEEN THE FRONT AND THE HIGH PRES BEHIND IT THE CONFIDENCE FOR EXPECTED GALE CONDITIONS HAS RISEN SO WILL KEEP CURRENT HIGHLIGHTED AREAS IN PLACE...AND EXTEND THEM N TO NEAR 27N W OF 95W FOR THU. THE HIGH PRES AREA WILL BUILD EWD ACROSS THE GULF THU...THEN BEGIN TO WEAKEN FRI AND AS IT SLIDES ENE JUST INLAND THE COASTAL PLAINS. THE STRONG N WINDS OVER THE WRN GULF WILL OVERSPREAD THE ENTIRE GULF THROUGH FRI WHILE BECOMING MORE N-NE IN DIRECTION WITH THE EWD PROGRESS OF THE HIGH OVER JUST INLAND THE NRN GULF COAST. WINDS ARE FORECAST TO BECOME NE 20-25 KT ACROSS MUCH OF CENTRAL AND EASTERN GULF BY FRI AFTERNOON...AND NE-E AT 15-20 KT ELSEWHERE WITH WINDS DIMINISHING TO LIGHTER SPEEDS E AT 10-15 KT IN THE NW PART BY LATE FRI THEN VEER AROUND TO THE SE SAT WITH THE EASTWARD TRANSLATION OF THE HIGH OVER THE NORTHERN GULF. BY SUN...THE WEAKENING HIGH SHOULD BE OVER THE FLORIDA PANHANDLE ALLOWING FOR WINDS TO BE E-SE 10-15 KT W OF 90W...AND N-NE 10-15 KT E OF 90W...WITH A SLIGHTLY TIGHTER GRADIENT IN THE FAR SE PORTION RESULTING IN N-NE 15-20 KT WINDS THERE. FOR SEAS BEHIND THE SECOND FRONT WILL LEAN TOWARDS THE MIDDLE OF THE GRIDDED WWIII AND ECMWF WAVES FOR MAX SEAS ON THU AND FRI WITH VALUES OF 13-14 FT IN THE SW GULF LATE THU INTO FRI...AND IN THE RANGE OF 8-13 FT ELSEWHERE. SEAS SLOWLY DECREASE FROM NW TO SE LATER FRI THROUGH SUN. SW N ATLC S OF 31N W OF 65W... THE 18 UTC PRELIMINARY ANALYSIS DEPICTS A WEAK RIDGE FROM NEAR 27N65W SW TO THE CENTRAL BAHAMAS...WHILE A COLD FRONT HAS MOVED INTO THE NW PORTION AND EXTENDS FROM 31N76W SW TO INLAND CENTRAL FLORIDA NEAR CAPE CANAVERAL. LATEST BUOY OBSERVATIONS ALONG WITH A SEVERAL SHIP REPORTS NOTE E-SE WINDS OF 10-15 KT S OF 27N W OF 67W EXCEPT S-SW 5-10 KT W OF THE BAHAMAS. NE-E 15-20 KT WINDS ARE SEEN IN THE FAR SE PART BETWEEN THE SE BAHAMAS AND PUERTO RICO. THE OBSERVATIONS REVEAL SEAS OF 5-7 FT IN NE SWELLS N OF 28N E OF 71W...AND 4-6 FT ELSEWHERE EXCEPT 4-7 FT S OF 24N BETWEEN 67W AND 70W. WIDELY SCATTERED SHOWERS ARE S OF 22N E OF 70W. MODELS ARE ON TRACK WITH FORECAST OF HIGH PRES ACROSS THE BASIN SLIDING E OF THE BASIN TONIGHT INTO WED. THIS WILL ALLOW FOR THE COLD FRONT TO MOVE TO A POSITION FROM NEAR 31N69W TO WESTERN CUBA BY LATE TONIGHT...THEN WEAKEN AND BECOME STATIONARY OVER THE FAR SE WATERS WED. HIGH PRES WILL BUILD ACROSS AREA BEHIND THE FRONT WITH LIGHT WINDS MOST ZONES WED INTO THU. THEN SW WINDS OF 20-25 KT WILL PRECEDE THE NEXT COLD FRONT N OF ABOUT 29N ON THU. THIS COLD FRONT WILL BE STRONGER THAN RECENT ONES...AND IS FORECAST BY THE MODELS TO MOVE OFF THE NE FLORIDA COAST LATE THU...REACH FROM NEAR 31N71W TO WESTERN CUBA FRI AFTERNOON...AND FROM NEAR 26N65W TO EASTERN CUBA BY LATE SAT. THE FRONT WILL BE FOLLOWED BY STRONGER NW WINDS OF 20-30 KT AS SUGGESTED PER GFS/ECMWF CONSENSUS WITH GALE FORCE WINDS JUST N OF 31N. BY SUN AFTERNOON THE DISSIPATING FRONT SHOULD BE LOCATED JUST TO THE SE OF THE AREA AS HIGH PRES BUILDS SE OVER THE FORECAST WATERS. WAVEWATCH GUIDANCES BUILD SEAS TO MUCH HIGHER LEVELS THAN THAT ASSOCIATED WITH THE FIRST FRONT WITH MAX VALUES OF 15 OR 16 FT PER THE GRIDDED WWIII GUIDANCE AND UP TO 20 FT PER THE ECMWF GUIDANCE ON SAT OVER THE N CENTRAL AND NE WATERS. WILL ADJUST FORECAST WAVE HEIGHTS FOR FRI AND SAT BY PERHAPS BLENDING THESE GUIDANCES...AND FOLLOW THE GRIDDED NOAA WWIII FOR SUN. CARIBBEAN SEA AND TROPICAL N ATLC S OF 22N W OF 55W... A RELATIVELY WEAK PRES GRADIENT CONTINUES AS WEAK ATLC HIGH REMAINS IN PLACE. THE ONGOING PRES GRADIENT WILL MAINTAIN GENTLE TO MODERATE TRADE WINDS THROUGH WED EXCEPT OVER THE S CENTRAL PORTION OF THE CARIBBEAN WHERE A TIGHTER GRADIENT IS RESULTING IN HIGHER WINDS THERE. THESE WINDS ARE EXPECTED TO DIMINISH SOME TUE AFTERNOON. STRONGER HIGH PRES WILL BUILD EASTWARD ACROSS THE WESTERN ATLC LATE WED THROUGH FRI INCREASING TRADES ACROSS MUCH OF THE CENTRAL CARIBBEAN WATERS. LARGE NW TO N SWELLS IN THE RANGE OF 8-14 FT ARE EXPECTED TO BEGIN TO IMPACT THE NORTHERN TROPICAL N ATLC THU AND FRI...AND STEADILY INCREASE THROUGH SUN AS ALL WAVEWATCH GUIDANCE ARE CONSISTENTLY DEPICTING. A WEAK SURFACE TO LOW TROUGH ALONG 65W FROM 14N-18N WILL CONTINUE WESTWARD ACROSS THE EASTERN CARIBBEAN WILL BECOMING DIFFUSE OVER THE CENTRAL CARIBBEAN WED NIGHT AND THU WITH ONLY ISOLATED SHOWERS ALONG AND WITHIN 180 NM OF IT. THE SRN PORTION OF THE ABOVE MENTIONED SECOND COLD FRONT IS FORECAST TO PUSH SE ACROSS THE NW PORTION OF THE TROPICAL N ATLC WATERS LATE SAT INTO SUN...BUT WILL BE IN THE DIFFUSING STAGE AS ATLC HIGH PRES BRIDGES SE ACROSS IT. NOTE...GRIDDED MARINE FORECAST IS AVAILABLE AT WWW.NHC.NOAA.GOV/TAFB/GRIDDED_MARINE GULF OF MEXICO... .GMZ017...GALE CONDITIONS EXPECTED THU W OF 96W... .GM023...GALE CONDITIONS EXPECTED THU AND FRI S OF 22N W OF 94W... .GMZ011...GALE CONDITIONS EXPECTED THU S OF 27N... CARIBBEAN SEA AND TROPICAL N ATLC... .NONE. SW N ATLANTIC... .NONE. FOR ADDITIONAL INFORMATION PLEASE VISIT WWW.HURRICANES.GOV/MARINE $$ FORECASTER AGUIRRE