000 AGXX40 KNHC 111946 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 245 PM EST FRI JAN 11 2013 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 PRELIMINARY 18 UTC SURFACE ANALYSIS DEPICTS THE PREVIOUSLY DESCRIBED COLD FRONT NOW AS A WEAKENING STATIONARY FRONT FROM S CENTRAL LOUISIANA SW TO 26N95W AND SSE TO THE WRN PORTION OF THE BAY OF CAMPECHE. NUMEROUS STRONG CONVECTION NOTED 24 HRS AGO HAS SINCE DISSIPATED. ELSEWHERE AN ATLC RIDGE AXIS STRETCHES INTO THE GULF FROM W CENTRAL FLORIDA WSW TO NEAR 26N89W. THE MOST RECENT AND LATEST BUOY AND PLATFORM OBSERVATIONS REVEAL DEEP LAYER MOIST SE-S WIND FLOW OVER THE AREA CONSISTING OF SE-S WINDS OF 10-15 KT EXCEPT FOR SLIGHTER HIGHER WINDS OF 20 KT WITHIN 180 NM E OF THE FRONT N OF 26N AND TO 25 KT AT THE PLATFORM HEIGHTS. SATELLITE WATER VAPOR IMAGERY SHOWS A NARROW UPPER TROUGH FROM THE FLORIDA PANHANDLE SW TO THE ERN BAY OF CAMPECHE EARLY THIS AFTERNOON...BUT IS LACKING INSTABILITY AS THE ATMOSPHERIC ENVIRONMENT IS RATHER DRY THROUGH ALL LEVELS. ONLY ISOLATED SHOWERS ARE OVER THE WRN GULF ALONG AND W OF THE FRONT. WILL FOLLOW CONTINUITY WITH PREVIOUS FORECASTS AND GENERAL MODEL CONSENSUS...AND FORECAST THE FRONT TO SLOWLY DISSIPATE THROUGH TONIGHT...WITH ITS REMAINING REMNANTS TO DRIFT W THROUGH SAT WHILE WASHING OUT AS ATLC HIGH PRES PERSISTS ELSEWHERE OVER THE AREA THROUGH SUN. MODELS CONTINUE TO SUGGEST THAT THE NEXT COLD FRONT ENTERS THE FAR WRN GULF EARLY ON SUN...AND JUST LIKE THE PRESENT ONE...SLOWLY PROGRESSES EWD TO A POSN FROM NEAR SE LOUISIANA TO SW GULF BY EARLY TUE. THE MAIN DIFFERENCE WITH THIS ONE WILL NE THAT AN AREA OF HIGH PRES WILL BUILD SEWD IN ITS WAKE USHERING IN NLY WIND FLOW OF 20-25 KT INTO THE FAR WRN GULF BEGINNING DURING SUN MORNING INTO TUE. WINDS E OF THIS FRONT SHOULD BE LIGHT TO MODERATE IN SE-S RETURN FLOW AROUND THE WRN PERIPHERY OF THE ATLC HIGH THAT BUILDS WWD. THE FRONT IS EXPECTED TO REACH A PSN FROM NEAR FROM SE LOUISIANA TO 26N94W TO INLAND MEXICO NEAR 18N95W MON AND FROM THE WESTERN FLORIDA PANHANDLE TO THE SW GULF BY LATE TUE...THEN MOVE A LITTLE FASTER WED AS THE HIGH PRES BEHIND INTENSIFIES PUSHING IT TO A POSN FROM NEAR CEDAR KEY FLORIDA SW TO NEAR 26N88W WHERE IT BECOME STATIONARY TO THE S CENTRAL BAY OF CAMPECHE. GFS IS A BIT MORE AGGRESSIVE WITH WINDS BEHIND IT FOR TUE AND WED INDICATING N WINDS OF 20-25 KT AT THE BNDRY LAYER. THE ECMWF IS SHOWING ABOUT 15-20 KT FOR THOSE SAME TIME PERIODS. FOR NOW WILL FORECAST 15-20 KT BEHIND THE FRONT ON TUE...AND MOST LIKELY INCREASE THESE WINDS TO 20-25 KT WED PENDING FUTURE MODEL TRENDS WITH STRENGTH OF THE HIGH THAT BUILDS IN BEHIND IT. CARIBBEAN SEA AND TROPICAL N ATLC S OF 22N W OF 55W... BUOYS AND A FEW SHIPS IN THE CENTRAL PORTION OF THE SEA SHOW NE-E WINDS OF 25-30 KT WINDS THERE S OF ABOUT 17N. THE POCKET OF GALE FORCE WINDS OF 30-35 KT THAT WAS NEAR THE COAST OF COLOMBIA HAS JUST RECENTLY LOWERED TO BELOW 35 KT BASED ON THE WEAKENING WRN ATLC HIGH PRES RIDGE...AND LOWER 34 KT WINDS PROBABILITIES EXHIBITED IN THE GFS MEAN ENSEMBLE. THE MAIN ISSUE IN THE SW CARIBBEAN WILL BE HIGH SEAS UP TO A 17 FT MAX THAT WILL BE SLOW IN SUBSIDING THROUGH SUN. ELSEWHERE...FRESH TO STRONG TRADES IN THE NW CARIBBEAN AND THE WINDWARD PASSAGE ARE EXPECTED TO DIMINISH FRI INTO THE WEEKEND AS THE RIDGE IN THE SW N ATLC WEAKENS. ERN CARIBBEAN SEAS ARE IN THE 7-9 FT IN NE SWELLS PER BUOY 42059 AT 15N67.5W. SIMILAR CONDITIONS ARE NOTED IN THE NRN AND CENTRAL PORTIONS OF THE TROPICAL N ATLC ZONES WATERS AS SEEN IN BUOYS THERE. ELSEWHERE OVER THE TROPICAL N ATLC...WINDS HAVE DIMINISHED COMPARED TO 24 HRS AND SEAS WILL CONTINUE TO SUBSIDE THROUGH SAT AS A LOW PRES SYSTEM DIVES SOUTHEASTWARD INTO THE CENTRAL ATLC AND WEAKENS THE SUBTROPICAL RIDGE THERE. AS OBSERVED IN PREVIOUS FORECAST DISCUSSIONS...THE ECMWF WAVE GUIDANCE IS A BIT FASTER IN CARRYING THE SWELL FROM THE CENTRAL ATLC SYSTEM S INTO THE TROPICAL ATLC THAN THE GFS BASED GRIDDED WWIII GUIDANCE BUT VERY CLOSE TO THE NAH GRIDDED WAVEWATCH AND UKMET WAVE GUIDANCE. FOR THIS FORECAST PACKAGE WILL BLEND THE 12 UTC GRIDDED WWIII AT 50/50 WITH THE PREVIOUS FORECAST WHERE IT HAD ALREADY INCORPORATED SOME OF THE ECMWF GUIDANCE...AND HOLD ON TO SEAS A BIT HIGHER IN THE SW CARIBBEAN SEA THROUGH SAT. WILL MAKE MINOR TWEAKS TO SEAS ELSEWHERE. SW N ATLC S OF 31N W OF 55W... THE 1350 UTC ASCAT PASS SHOWED A SWATH OF NE 20 KT WINDS OVER THE THE SRN PORTION OF THE ERN WATERS. THE TIGHT PRES GRADIENT OVER THE SRN PORTION OF THE BASIN WILL GRADUALLY LESSEN THROUGH SAT AT WHICH TIME THE STRONG HIGH CENTER LOCATED N OF THE AREA DROPS S AND WEAKENS. SEAS WILL REMAIN IN THE HIGH RANGE IN RESIDUAL N SWELLS THROUGH THE WEEKEND OVER THE SRN AND ERN PORTIONS OF THE BASIN. AS MENTIONED IN THE SECTION ABOVE...THE GRIDDED WAVEWATCH III IS A BIT SLOWER THAN THE ECMWF WAVE GUIDANCE TO SPREAD THE SWELL WESTWARD INTO THIS AREA. WILL KEEP CONTINUITY WITH PREVIOUS FORECAST THINKING WITH RESPECT TO WAVE HEIGHTS PRIMARILY IN THE ERN AND SE PORTIONS OF THIS BASIN THROUGH THE PERIOD. THE NEXT COLD FRONT IS NOT EXPECTED TO ENTER THE AREA UNTIL EARLY WED WHEN IT PUSHES INTO THE NW WATERS...BUT THE LATEST MODEL RUNS DEPICT IT AS BEING RATHER WEAK WITH WINDS OF 10-15 KT ON EITHER SIDE OF IT WITH WEAK HIGH PRES CENTERED OVER THE CENTRAL PORTION OF THE BASIN BY THEN. NOTE...GRIDDED MARINE FORECAST IS AVAILABLE AT WWW.NHC.NOAA.GOV/TAFB/GRIDDED_MARINE WARNINGS... GULF OF MEXICO... .NONE. CARIBBEAN SEA AND TROPICAL N ATLC... .NONE. SW N ATLC... .NONE. FOR ADDITIONAL INFORMATION PLEASE VISIT WWW.HURRICANES.GOV/MARINE $$ FORECASTER AGUIRRE