000 AGXX40 KNHC 201804 MIMATS MARINE WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 200 PM EDT THU SEP 20 2007 MARINE WEATHER DISCUSSION FOR GULF OF MEXICO...CARIBBEAN SEA AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W. GULF OF MEXICO...UPPER LOW CENTERED NEAR 27N84W IS MAKING SLOW PROGRESS WNW...INTO AN UPPER ANTICYCLONE CENTERED OVER THE PANHANDLE OF TEXAS. SHIP AND BUOY OBSERVATIONS SHOW A SURFACE LOW HAS FORMED THIS MORNING BENEATH THE UPPER LOW NEAR 27N84W...WITH FRESH TO STRONG WINDS WITHIN 90 NM OF THE CENTER. CONVECTION REMAINS FAIRLY LIMITED AND DISORGANIZED AT THIS TIME...ALTHOUGH THERE IS AMPLE OPPORTUNITY FOR CONVECTIVE DEVELOPMENT AS THE SYSTEM MOVES SLOWLY WWD INTO THE MORE FAVORABLE WATERS OF THE LOOP CURRENT TONIGHT AND FRI. THE LOW MAY FORM INTO A SUBTROPICAL OR EVEN TROPICAL SYSTEM IN THE NEXT COUPLE OF DAYS. GLOBAL MODEL GUIDANCE SUGGESTS THAT THE LOW WILL CONTINUE ON A WNW TRACK REACHING THE LOUISIANA COAST ON SAT. DRY CONTINENTAL AIR IS ADVECTING INTO THE WRN GULF WATERS. GENERALLY LIGHT TO MODERATE NLY FLOW IS EXPECTED OVER THE WRN GULF. CARIBBEAN AND TROP N ATLC...UPPER LOW IS CENTERED NEAR 22N67W N OF PUERTO RICO. ALONG WITH THE UPPER LOW OVER THE GULF OF MEXICO...THIS IS MAINTAINING WLY SHEAR ALOFT ACROSS THE CARIBBEAN...IMPEDING SIGNIFICANT CONVECTIVE GROWTH. THE ONLY EXCEPTION IS IN THE FAR SW CARIBBEAN WHERE WEAK UPPER LEVEL FLOW AND DECENT LOW LEVEL CONVERGENCE IS AIDING MODEST CONVECTION...ALBEIT WEAKENING...FROM COLOMBIA TO NICARAGUA. A TROPICAL WAVE IS ENTERING THE EASTERN CARIBBEAN...AND WILL MIGRATE TO THE WESTERN CARIBBEAN OVER THE NEXT THREE DAYS. MODERATE TO FRESH TRADE WIND FLOW IS EVIDENT IN SCATTEROMETER DATA N OF COLOMBIA AND VENEZUELA. THIS AREA OF STRONGER WINDS WILL EXPAND SLIGHTLY FRI AND SAT AS RIDGING TO THE N BUILDS OVER THE AREA BEHIND THE WWD MOVING TROPICAL WAVE. THERE IS SOME INDICATION IN THE ENSEMBLE GFS THAT WINDS WILL ALSO INCREASE OVER THE NW CARIBBEAN NEAR THE YUCATAN CHANNEL BY SUN BEHIND THE WAVE...AS WELL...BUT THIS IS NOT GENERALLY SUPPORTED BY OTHER GLOBAL MODELS. FOR THE TROP N ATLC...TRADE WIND FLOW INCREASE SLIGHTLY S 15N INTO THE WINDWARD ISLANDS THIS WEEKEND AS HIGH PRES BUILDS TO THE N. SW N ATLC...STRONG WINDS AND SEAS THAT WERE NOTED OVERNIGHT N OF THE BAHAMAS RELATED TO BROAD LOW PRES OVER CENTRAL FLORIDA HAVE DIMINISHED THIS MORNING AS THE LOW DISSIPATED. RELATED CONVECTION HAS GENERALLY SHIFT N OF THE AREA AS WELL. THE ONLY OTHER FEATURE OF NOTE IS A WEAK SURFACE TROUGH...THE REMNANTS OF INGRID...STILL CLINGING TO LIFE N OF PUERTO RICO. THIS IS EXPECTED TO DAMPEN OUT OVER THE NEXT DAY...LEAVING A DEEP LAYER RIDGE IN CONTROL OF THE WRN ATLC THROUGH THE WEEKEND. THE SURFACE RIDGE AXIS WILL BECOME ESTABLISHED GENERALLY ALONG 29N BY FRI...ALLOWING MODERATE ELY FLOW ACROSS THE AREA WITH GRADUALLY DIMINISHING SEAS. WARNINGS... ATLANTIC... NONE. CARIBBEAN... NONE. GULF OF MEXICO... NONE. FORECASTER CHRISTENSEN