000 AGXX40 KNHC 211910 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 310 PM EDT FRI SEP 21 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... LATEST BUOY AND OIL PLATFORM OBSERVATIONS FROM AROUND THE GULF SHOW RATHER LIGHT E-SE WINDS OF 10 KT W OF 86W...AND NE WINDS OF 10 KT E OF 86W. PARTIAL HIGH RESOLUTION ASCAT PASSES FROM BETWEEN 15 UTC AND 16 UTC THIS MORNING CORROBORATED THESE WINDS. THE BUOY REPORTS SHOW SEAS OF 2-3 FT WITH THE EXCEPTION OF 1-2 FT IN FAR EASTERN PORTION. THE WINDS IN THE BUOY AND ASCAT DATA FROM THIS MORNING AND EARLY AFTERNOON CONTINUE TO DEPICT A LARGE INVERTED TROUGH THAT EXTENDS ROUGHLY 94W FROM SW LOUISIANA TO MEXICO AT 19N93W. IN THE UPPER LEVELS...PERSISTENT BROAD SCALE TROUGHING IS PRESENT OVER THE WESTERN PORTION OF THE GULF ENHANCING ABUNDANT DEEP ATMOSPHERIC MOISTURE AND SCATTERED SHOWERS AND TSTMS ACROSS MUCH OF THE AREA. THE UPPER TROUGH WILL GRADUALLY LIFT NE THROUGH SUN WHILE BROADENING AND WEAKENING. THIS WILL ALLOW FOR THE ATMOSPHERIC MOISTURE CURRENTLY IN PLACE TO THIN OUT WITH THE SURFACE TROUGH ALONG 94W DISSIPATING. WITH THE UPPER TROUGH WEAKENING...THIS WILL IN TURN ALLOW FOR HIGH PRES TO BUILD S ACROSS MAINLY THE ACROSS THE NORTHERN AND CENTRAL GULF WATERS. A WEAK COLD FRONT WILL SWEEP ACROSS THE EASTERN GULF SUN NIGHT AND MON LEADING THE SURGE OF THE HIGH PRES BUILDING S. WINDS BECOME NE-E 10-15 KT ACROSS MUCH OF THE ZONES OF THE NORTHERN AND CENTRAL GULF SUN NIGHT THROUGH TUE WITH A BRIEF INSTANCE OF N-NE WINDS OF 15-20 KT IN THE NE PART OF THE GULF SUN NIGHT AND MON BEFORE DIMINISHING TO 10-15 KT. WINDS BECOME NE-E 10-15 KT THROUGHOUT MUCH OF THE GULF DURING TUE AND WED. SEAS REMAIN RATHER LOW...EXCEPT FOR SEAS BUILDING TO 3-5 FT IN THE NE PART OF THE GULF SUN NIGHT THEN SUBSIDING TO 2-3 FT MON THROUGH WED. A TROPICAL WAVE OVER THE WESTERN CARIBBEAN SEA NEAR 85W WILL MOVE INLAND THE YUCATAN PENINSULA LATE TONIGHT AND EARLY SAT... AND ACROSS THE BAY OF CAMPECHE SAT THROUGH SUN NIGHT WITH THE ONLY IMPACT SEEN AS A POSSIBLE ENHANCEMENT TO CONVECTION OVER THOSE WATERS. SOUTHWEST NORTH ATLC S OF 31N W OF 55W... THE PRELIMINARY 18 UTC SURFACE ANALYSIS HAS A WEAKENING STATIONARY STATIONARY FRONT EXTENDING FROM NEAR 31N74W SW TO INLAND CENTRAL FLORIDA NEAR DAYTONA BEACH. EXTENSIVE DEEP MOISTURE CONTINUES TO STREAM NEWD FROM THE GULF OF MEXICO TO ACROSS THE FLORIDA PENINSULA...AND TO NEAR 77W IN ADVANCE OF THE UPPER TROUGH OVER THE WESTERN GULF OF MEXICO. AS A RESULT OF THE ATMOSPHERIC INSTABILITY...SCATTERED SHOWERS AND TSTMS WITH POSSIBLE GUSTY WINDS ARE OCCURRING OVER MUCH OF THE WESTERN PART OF THE AREA. ELSEWHERE WEAK HIGH PRES IS PRESENT OVER MUCH OF THE ZONE W OF ABOUT 70W. BOTH ASCAT DATA AND BUOY REPORTS ARE SHOWING RELATIVELY LIGHT WINDS THROUGHOUT...MAINLY FROM THE NE IN DIRECTION. SEAS ARE 2-3 FT...EXCEPT FOR 3-4 FT IN A NE SWELL E OF 72W AS BUOY 41047 AT 27.5N71.5W IS REVEALING. MODELS ARE IN GOOD AGREEMENT THAT A COLD FRONT MOVES INTO THE NW PORTION SUN MORNING. THIS IS A LITTLE FASTER THAN PREVIOUS MODEL RUNS HAD INDICATED...BUT WITH THE MODEL CONSENSUS NOW INDICATING SUN MORNING FOR COLD FRONT ENTRY INTO THE AREA...WILL FOLLOW GUIDANCE CLOSELY WITH RESPECT TO WINDS BEHIND THE FRONT THROUGH MON NIGHT BEFORE HIGH PRES IN IN ITS WAKE OVERTAKES IT. BEFORE THEN...THE FRONT WILL SLOWLY DROP TO ACROSS CENTRAL FLORIDA BEFORE WASHING OUT AS THE RIDGE BUILDS SWD. WINDS BEHIND THE FRONT START OF AS NW AT 10 KT...THEN QUICKLY SHIFT TO THE NE-E DURING SUN AND SUN NIGHT...AND BECOME MORE ELY IN DIRECTION MON NIGHT THROUGH WED AT 10-15 KT. LITTLE CHANGE WILL BE EXPECTED WITH SEAS INTO DAY 5 (WED) WITH ONLY A SLIGHT INCREASE POSSIBLE IN THE FAR NW AND SE WATERS MON NIGHT AND INTO WED. CARIBBEAN SEA AND TROPICAL N ATLC W OF 55W... GENTLE TO MODERATE TRADE WINDS PREVAIL ACROSS THE CARIBBEAN WATERS AND THE TROPICAL N ATLC WATERS...EXCEPT FOR FRESH NE-E WINDS IN THE S CENTRAL CARIBBEAN WATERS WHERE SEAS ARE UP TO 8 FT. SEAS ELSEWHERE ARE IN THE 3-5 FT RANGE...EXCEPT 2-3 FT OVER SOME SPOTS OF THE EASTERN AND NW CARIBBEAN SEA. A TROPICAL WAVE NEAR 85W WILL MOVE INLAND THE YUCATAN PENINSULA TONIGHT AND EARLY SAT. WITH THE PERSISTENCE OF THE FRESH NE-E WINDS IN THE S CENTRAL PORTION EXPECT SEAS THERE TO BUILD TO 9 OR 10 FT...FOLLOWING THE NWWIII MODEL GUIDANCE AND NWWIII/FNMOC ENSEMBLE PROBABILITY GUIDANCE...OVER THE NEXT 24 TO 48 HRS BEFORE SUBSIDING AGAIN. A WEAK TROPICAL WAVE EARLIER ANALYZED OVER THE NE CARIBBEAN SEA IS HARD TO IDENTIFY AT THE SURFACE AT THIS TIME...SO WILL NOT MENTION IMPACTS TO WIND AND SEAS FOR THIS FORECAST UNTIL OR IF IT BECOMES MORE EVIDENT AT THE BNDY LAYER. ANOTHER WEAK TROPICAL WAVE OVER THE FAR SE PORTION OF THE SW N ATLC IS ALSO ILL-DEFINED AT THIS TIME. AN UPPER LEVEL LOW OVER THE WINDWARD ISLANDS IS PRODUCING SCATTERED SHOWERS AND TSTMS THERE AND OVER THE WATERS ADJACENT TO THOSE ISLANDS. THE LOW IS FORECAST TO MOVE WWD...AND BE LOCATED OVER THE CENTRAL CARIBBEAN ON WED. THE NEXT TROPICAL...CURRENTLY IN THE EASTERN ATLC...IS EXPECTED TO REACH THE TROPICAL N ATLC WATERS SUN....ACCOMPANIED BY A BROAD LOW LEVEL WIND SURGE AND SEAS OF NEAR 8 OR 9 FT. THE WAVE SHOULD MOVE THROUGH THE EASTERN CARIBBEAN SEA MON AND TUE AND BEGIN TO MOVE ACROSS THE CENTRAL CARIBBEAN WED. 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