000 AGXX40 KNHC 051858 MIMATS MARINE WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 300 PM EDT SUN SEP 05 2010 MARINE WEATHER DISCUSSION FOR THE GULF OF MEXICO...CARIBBEAN SEA AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W. GULF OF MEXICO... QUASI STATIONARY FRONTAL TROUGH ACROSS FAR N GULF HAS BEGUN TO MERGE WITH LLVL TROUGH/MOISTURE DISCONTINUITY ACROSS THE NE GULF...WITH ACTIVE CNVTN CONTINUING. S-SE FLOW SPREADING FROM THE NW CARIB AND ACROSS THE YUCATAN HAS HELPED TO MAKE LLVL TROFFING ACROSS THE SW AND W GULF MORE N TO S ALIGNED. ALVARADO, MEXICO RADAR HAS SHOWN A SMALL LOW OFF THE MEXICAN COAST NEAR 19.5N95.5W THIS MORNING THAT LOOKS TO HAVE BEGUN TO DRIFT N VIA VIS IMAGERY THIS AFTERNOON. THIS LOW AND ASSOCIATED TROF WILL SHIFT NW NEXT 48 HOURS...WITH LOW LIKELY TO BE INLAND BY 36 HOURS. THIS GIVES IT A VERY SHORT WINDOW OF OPPORTUNITY TO INTENSIFY INTO A TROPICAL CYCLONE. HAVE GONE WITH A BLEND OF THE GFS AND ECMWF...AS THEY ARE ON CLOSER AGREEMENT TODAY. 20-25 KT SE FLOW WILL PREVAIL E OF THE TROUGH TO ABOUT 90W AND PUMP UP SEAS TO 9 FT DURING THE NEXT 24 HOURS...SPREADING ALL THE WAY TO THE SE TEXAS COASTAL WATERS. HIGH PRES AND MORE E TO SE FLOW WILL THEN PREVAIL AS HIGH PRES BUILDS ACROSS THE N HALF. SW N ATLC... HIGH PRES CENTERED ACROSS CENTRAL ATLC RIDGES W-SW TO FL STRAITS. A FRONTAL TROUGH IS ALONG THE GA COAST AND IS EXPECTED TO STALL AND MEANDER OVER THE EXTREME NW WATERS THROUGH MON BEFORE DISSIPATING. A LLVL REFLECTION OF UPPER LEVEL TROUGH MOVING ACROSS THE NE CARIB HAS PRODUCED A N TO S TROUGH ALONG ABOUT 64W EXTENDING FROM THE NE CARIB INTO THE SW N ATLC AND INDUCING NELY FLOW TO ITS W. THIS FEATURE WILL SHIFT W NEXT 24-36 HOURS AND WEAKEN AND ALLOW MODERATE ELY TRADES TO BUILD ACROSS SE AND S PORTIONS. FORECAST UNCERTAINTY THEN INCREASES AS REMNANTS OF GASTON ARE FORECAST TO PASS TO THE S. TROPICAL CYCLONE GUIDANCE SUGGESTS W TRACK ALONG ABOUT 17N AND DEVELOPING TO HURRICANE STRENGTH. CONVECTION IS NOT PERSISTENT...THUS SYSTEM HAS NOT BEEN UPGRADED. IN ANY EVENT...EXPECT A TROPICAL LOW TO TRACK W THROUGH THE NE CARIBBEAN WITH E TRADES INCREASING...AND PERHAPS BACKING SLIGHTLY TO THE NE...AS EARLY AS TUE EVENING OVER THE PUERTO RICO COASTAL WATERS. E-SE SWELLS SHOULD ALSO ARRIVE BUILDING SEAS TO 6-8 FT OVER AREA S OF 23N E OF THE BAHAMAS WED AND THU. CARIBBEAN SEA AND TROPICAL N ATLC... SE FLOW IS AT 15-25 KT ACROSS THE GULF OF HONDURAS AND E AT 15-20 KT THROUGH THE SRN CARIB W OF 70W AND ALONG N COAST OF COLOMBIA. EXPECT LITTLE CHANGE THROUGH SUN...THEN PRES GRADIENT WILL RELAX SOME OVER THE S CENTRAL WATERS AND SPREADING W TO THE GULF OF HONDURAS ON WED NIGHT INTO THU. PLENTY OF UNCERTAINTY THIS UPCOMING WEEK AS REMNANTS OF GASTON ARE EXPECTED TO REGENERATE AND TRACK W ACROSS THE NE CARIBBEAN ALONG 17N. ALTHOUGH TC GUIDANCE SUGGESTS EVENTUAL HURRICANE STRENGTH...INGESTION OF SAL WITHIN THE CORE CIRCULATION HAS INHIBITED WIDESPREAD AND LONG LIVED CNVTN PAST FEW DAYS. CURRENTLY CONVECTION APPEARS TO BE MAKING A COMEBACK NEAR THE CENTER OF THIS LOW...AND IT IT PERSISTS LONG ENOUGH THE SYSTEM COULD BE QUICKLY UPGRADED. HAVE CONTINUED TO MOVE TROPICAL LOW W ACCOMPANIED BY CYCLONIC WINDS OF 20-30 KT AND SEAS 8-12 FT. PRESSURE GRADIENT...AND THUS WIND AND SEAS FORECASTS...OVER REMAINDER OF AREA VERY DEPENDENT ON STRENGTH AND TRACK OF THIS TROPICAL LOW...SO EXPECT A LOT OF TWEAKING IN EACH FORECAST PACKAGE OVER THE NEXT FEW DAYS TILL WE GET A BETTER HANDLE ON REMNANTS OF GASTON. WARNINGS... SUBJECT TO CHANGE BASED ON LATEST NHC ADVISORY SW N ATLC... .NONE. CARIBBEAN... .NONE. TROPICAL N ATLC... .NONE. GULF OF MEXICO... .NONE. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ FORECASTER STRIPLING