000 AGXX40 KNHC 111853 MIMATS MARINE WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 130 PM EST THU JAN 11 2007 MARINE WEATHER DISCUSSION FOR GULF OF MEXICO...CARIBBEAN SEA AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W. UPPER LEVELS... UPPER LEVEL TROUGH AXIS DIGS SW FROM 31N71W TO 20N82W LITERALLY SPLITTING PREVIOUSLY WELL ANCHORED BROAD UPPER LEVEL RIDGE IN TWO SMALLER ONES. MOISTURE ADVECTED BY 75 KT JET CORE ON LEE SIDE OF TROUGH IS ONLY TRACE OF MOISTURE ALOFT IN ENTIRE REGION E OF 90W. EASTERNMOST RIDGE ALONG 55W CONTINUES WEAKENING AND FORCED E BY TROUGH LIKELY TO DECREASE SUPPORT TO SURFACE TRADES ACROSS TROPICAL ATLANTIC. WESTERNMOST RIDGE APPEARS TO BE BUILDING ALTHOUGH NEW UPPER LEVEL TROUGH APPROACHES FROM THE W WITH STRONG JET AND ABUNDANT TROPICAL MOISTURE ADVECTED FROM E PAC. NEW TROUGH SHOULD SWEEP THROUGH GULF OF MEXICO LATE IN FORECAST PERIOD. AT THE SURFACE... GULF OF MEXICO WRN EXTENSION OF ATLC RIDGE CONTROL ANTICYCLONIC FLOW THROUGH ENTIRE GULF. DRY CONDITIONS ALOFT E OF 90W DUE TO UPPER RIDGE SUBSIDENCE CONTRAST WITH APPROACHING MOISTURE AT HIGHER LEVEL DUE TO MENTIONED TROUGH. LOW LEVEL CONVERGENCE ALONG COASTAL WATERS ADDS BROKEN LOW LEVEL CLOUDS. ENTRANCE OF NEXT COLD FRONT INTO NW GULF LATE SUN EVENING WILL BE NEXT FEATURE IN WIND AND SEA FORECASTS. SEEMS LIKE ANOTHER SHOT OF POLAR AIR MASS WILL COVER ENTIRE GULF BY LATE TUE. GFS HAS KEPT A GOOD HANDLE ON TIMING AND WINDS WHILE SEA HEIGHTS HAVE BEEN SLIGHTLY OVERDONE MAINLY IN SW GULF. BOTH GFS AND NOGAPS BACKING OUT OF GALE FORCE WINDS IN BAY OF CAMPECHE BUT KEEP WINDS NEAR 30 KT. SW N ATLC LITTLE CHANGE HAS FORECASTED FOR REGION AS COLD FRONT EXITS SE CORNER TONIGHT AND BROAD RIDGE TAKES OVER AS DOMINANT FEATURE. STRONG AND GUSTY WIND WITH SEAS ABOVE 15 FT EXPECTED THROUGHOUT MOST BASIN...EXCEPT NORTHERNMOST LATITUDES...TILL SAT. THEN RIDGE RETREATS E RELAXING GRADIENT AND ALLOWING WIND AND SEAS TO DIMINISH. NEW COLD FRONT ENTERS SW N ATLC EARLY TUE. GFS NOT TAKING SWELLS INTO SERIOUS CONSIDERATION AS SHIP REPORTS SOMETIMES DOUBLE MODEL SOLUTIONS. CARIBBEAN HEALTHY SURFACE RIDGE KEEPS BRISK TRADES ACROSS MOST BASIN. LOW PRES 1007 MB OVER COLOMBIA HELPS MAINTAIN 30 KT ALONG ITS COAST. CONDITIONS LIKELY TO CONTINUE WITH LITTLE DECREASE IN WIND AND SEAS THROUGH MOST FORECAST AND OUTLOOK PERIODS. WARNINGS... ATLANTIC... NONE. CARIBBEAN... NONE. GULF OF MEXICO... NONE. FORECASTER WALLY BARNES