000 AGXX40 KNHC 171924 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 320 PM EDT WED OCT 17 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 WEAK PRES PATTERN REMAINS ACROSS THE SE U.S. AND GULF TODAY ...WHILE A DISSIPATING STATIONARY FRONT STRETCHES FROM NEAR FORT MYERS FLORIDA SW TO 26N85W...AND NW TO INLAND SW LOUISIANA. BOTH BUOY AND OIL PLATFORM OBSERVATIONS SHOW RELATIVELY LIGHT SLY WINDS THROUGHOUT...WITH THE EXCEPTION OF THE WRN PORTION WHERE SLY FLOW HAS INCREASED TO 15 KT AND TO 20 KT ON THE HIGHER PLATFORMS THERE. THE LIGHT WINDS IN THE S CENTRAL PORTION ARE LIGHT AND VARIABLE IN DIRECTION. SEAS ARE IN THE GENERAL RANGE OF 2-3 FT...EXCEPT FOR SMALL POCKETS OF 3-4 FT IN THE WRN PART OF THE GULF. THESE SEAS MATCH VERY WELL WITH THE LATEST NOAA WAVEWATCH GUIDANCE SO WILL RELY ON THIS GUIDANCE FOR THIS PACKAGE. THE PRELIMINARY 18 UTC SURFACE MAP HAS A DISSIPATING STATIONARY FRONT EXTENDING FROM NEAR VENICE FLORIDA TO 26N90W. A SHORTWAVE TROUGH IS SEEN ON WATER VAPOR IMAGERY EXTENDING FROM SE GEORGIA SW TO NEAR 24N88W. AMPLE DEEP ATMOSPHERIC MOISTURE AHEAD OF THE TROUGH IS RESULTING IN SCATTERED SHOWERS AND ISOLATED TSTMS TO BE OVER THE SE GULF WATERS...WHILE DRIER AIR IS ADVECTING SE BEHIND THE TROUGH. THIS SHORTWAVE TROUGH IS FORECAST TO PUSH E OF THE GULF TONIGHT AS THE STATIONARY FRONT DISSIPATES. ANOTHER SHORTWAVE TROUGH OVER THE MID-WEST REGION OF THE COUNTRY QUICKLY MOVES ACROSS NE TEXAS AND SW LOUISIANA TONIGHT PUSHING A SURFACE COLD FRONT OFF THE TEXAS COAST LATE TONIGHT. THIS FRONT WILL QUICKLY REACH FROM FROM NEAR TAMPA FLORIDA TO BROWNSVILLE TEXAS BY FRI MORNING. SCATTERED SHOWERS AND A FEW TSTMS ARE EXPECTED WITH THIS FRONT. THE FRONT WILL DISSIPATE FROM NEAR FORT MYERS FLORIDA TO SE TEXAS SAT...HOWEVER MODELS SUGGEST THAT ITS WRN PORTION BECOMES STATIONARY THU AND LIFTS NNE AS A WEAK BOUNDARY TROUGH SAT. THE MODELS INDICATE THAT N-NE WINDS OF 15 KT WILL OCCUR BEHIND THE FRONT ON THU OVER THE NW GULF WITH SEAS OF 3-5 FT. THE GFS IS THE EXCEPTION WITH 15-20 KT. WILL LEAN TOWARDS NE 15 KT FOR NOW...WITH 15-20 KT MAINLY CONFINED TO THE COASTAL SECTIONS. WEAK SURFACE HIGH PRES WILL THEN BUILD ACROSS THE AREA SAT INTO MON. SW N ATLC S OF 31N W OF 65W... THE PRELIMINARY 18 UTC ANALYSIS HAS A WEAKENING STATIONARY FRONT EXTENDING FROM NEAR 31N72W TO NEAR WEST PALM BEACH WHILE A WEAK PRES PATTERN WITH LIGHT IS PRESENT ELSEWHERE. THE TRAILING TROUGH FROM HURRICANE RAFAEL WELL NORTH OF THE REGION IS DEFINED BY BOTH SATELLITE IMAGERY AND MORNING ASCAT DATA TO EXTEND FROM 22N64.5W SW TO NEAR 21N69W. SCATTERED SHOWERS AND TSTMS ARE WITHIN 60-75 NM OF THE TROUGH. BUOYS ARE SHOWING LINGERING N SWELLS FROM HURRICANE RAFAEL PERSISTING OVER THE ERN PORTION OF THE AREA RESULTING IN SEAS OF 7-9 FT THERE. ELSEWHERE SEAS ARE IN THE 4-7 FT RANGE WITH THE HIGHEST OF THIS RANGE IN THE NRN PORTION. THE SWELLS WILL SLOWLY SUBSIDE THROUGH THU NIGHT... HOWEVER 6-8 FT SEAS IN MAINLY A NE SWELL COMPONENT SHOULD LAST OVER THE NE PORTION INTO FRI. MODELS DEPICT THAT HIGH PRES WILL BUILD SW FROM THE CENTRAL ATLC OVER THE AREA THROUGH FRI AS THE TRAILING TROUGH FROM RAFAEL DISSIPATES. THE HIGH THEN BEGINS TO SHIFT EASTWARD THROUGH SAT ALLOWING FOR THE NEXT COLD FRONT TO ENTER THE NW WATERS FRI. THIS FRONT WILL REACH FROM NEAR 31N74W TO WEST PALM BEACH BY SAT ...FROM 31N71W TO WEST PALM BEACH BY SUN...AND BECOME STATIONARY WHILE WEAKENING FROM NEAR 26N65W TO THE SE BAHAMAS BY MON. STRONGER HIGH PRES BUILDS SE BEHIND THIS FRONT WITH A TIGHTER PRES GRADIENT BRINGING NE WINDS OF 15-20 KT TO MUCH OF THE NORTHERN AND CENTRAL WATERS WITH SEAS POSSIBLY BUILDING TO 5-6 FT. CARIBBEAN SEA AND TROPICAL N ATLC W OF 55W... BROAD CYCLONIC LLVL FLOW ASSOCIATED WITH AN ACTIVE MONSOON TROUGH AXIS TROUGH IN THE SW CARIBBEAN IS PRODUCING SCATTERED SHOWERS AND TSTMS IN THE SW AND ERN PORTIONS OF THE SEA. A WEAK LOW HAS BEEN IDENTIFIED ON THE MONSOON TROUGH NEAR 11N79W. LIGHT WINDS PREVAIL THROUGHOUT WITH SEAS OF 1-3 FT...EXCEPT IN THE TROPICAL N ATLC WHERE MIXED N AND NE SWELLS ARE RESULTING IN 5-6 FT SEAS OVER THE NRN AND CENTRAL PORTIONS OF THAT ZONE. THE OTHER FEATURE OF NOTE IS A LOW LEVEL TROUGH ALONG 58W S OF 15N WILL MOVE W NW ACROSS THE REMAINDER OF THE SW TROPICAL N ATLC TONIGHT AND THU...BUT ONLY BE ATTENDANT BY WIDELY SCATTERED TO SCATTERED SHOWERS AND TSTMS. A TROPICAL WAVE IN THE FAR ERN ATLC IS EXPECTED TO APPROACH THE ERN PART OF THE TROPICAL N ATLC MON. THE LOW NEAR 11N79W IS FORECAST BY GENERAL MODEL CONSENSUS TO REMAIN NEARLY STATIONARY THROUGH THE 24-36 HRS...THEN BEGIN TO MOVE IN A GENERAL NW DIRECTION. THE 12 UTC GFS IS STILL MOE OPEN WITH RESPECT TO EXACT TRACK OF THE LOW AFTER 48 HRS KEEPING THE FEATURE RESEMBLING THE MONSOON TROUGH IN THE SRN CARIBBEAN SEA. WILL FOLLOW GENERAL CONSENSUS WHICH IS IN LINE WITH THE MIDDAY HPC/NHC CONFERENCE CALL ON FORECASTING THE LOW NEAR 14N82W BY DAY 3...AND TAKING IT SLOWLY NW INTO DAY 5. BASED ON THIS SCENARIO THE PRES GRADIENT IS EXPECTED TO INCREASE TO ITS N AND NE DAYS 3-5 WITH UNCERTAINTY IN EXACT WINDS SPEEDS AND WAVE HEIGHTS. 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. FOR ADDITIONAL INFORMATION PLEASE VISIT WWW.HURRICANES.GOV/MARINE $$ FORECASTER AGUIRRE