000 AGXX40 KNHC 060732 MIMATS MARINE WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 330 AM EDT SUN SEP 06 2009 MARINE WEATHER DISCUSSION FOR THE GULF OF MEXICO...CARIBBEAN SEA AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W. GULF OF MEXICO...WEAK PRES GRADIENT WILL PERSIST OVER THE GULF MUCH OF THE FORECAST PERIOD WITH LIGHT WINDS AND SEAS LESS THAN 3 FT. WINDS WILL GENERALLY BE OUT OF THE E OR SE WITH THE EXCEPTION LYING ON THE W SIDE OF THE INVERTED SURFACE TROUGH MOVING NW INTO THE SE GULF MON/TUE AND PASSING INTO THE MIDDLE GULF WED/THU. AN AMPLIFIED UPPER TROUGH FROM FAR EASTERN GULF OF MEXICO THROUGH WESTERN CUBA INTO THE NW CARIBBEAN IS SUPPORTING A SURFACE REFLECTION CURRENTLY OVER THE CENTRAL BAHAMAS AND CENTRAL CUBA. SHORTWAVE ENERGY MOVING THROUGH NORTHERN MEXICO IS EXPECTED TO DROP INTO THE BACKSIDE OF THIS DEEP LAYERED TROUGH...DRAWING THE SURFACE TROUGH THROUGH THE STRAITS OF FL MON AND INTO THE MIDDLE GULF BY WED/THU. WINDS WILL SHIFT NE ON THE W SIDE OF THIS SURFACE TROUGH AND THERE WILL BE AN INCREASE IN THE CHANCE OF SHOWERS AND TSTMS IN THE MOIST SE FLOW ON THE E SIDE OF THE TROUGH. SW ATLC...UPPER LOW CURRENTLY NEAR 29N68W WILL MEANDER OVER NE WATERS THROUGH TUE BEFORE IT MOVES INTO THE LEADING EDGE OF THE ADVANCING EASTERN CONUS BROAD TROUGH AND PUSHES E OF THE AREA TUE. EXPECT SCATTERED CONVECTION ASSOCIATED WITH THIS LOW. AT THE SURFACE...THE ASCAT PASS FROM 0128 UTC SUGGESTS SURFACE TROUGHING ASSOCIATED WITH THE REMNANTS OF ERIKA EXTENDING ALONG 67W-68W TOWARD THE SURFACE REFLECTION OF THE UPPER LOW. IT IS DIFFICULT TO DISCERN THE REMNANTS OF ERIKA UNDER THE STRONG WESTERLY UPPER LEVEL FLOW BETWEEN AN ANTICYCLONE TO THE S NEAR 14N75W AND BROAD TROUGHING...INCLUDING THE AFOREMENTIONED UPPER LOW...N OF 20N. THIS SHEAR WILL INHIBIT ANY DEVELOPMENT IN THE NEAR-TERM AND MOST OF THE REMNANT ENERGY IS EXPECTED TO BE LIFTED NORTHWARD INTO THE LEADING EDGE OF THE DEEP LAYERED BROAD TROUGH. NOON MEDIUM RANGE CONFERENCE CALL YESTERDAY AGREED TO LIFT THE REMNANTS OF ERIKA NORTHWARD ALONG 72W MON NIGHT THROUGH WED BEFORE DISSIPATING. THIS IS CONSISTENT WITH THE CURRENT MODEL CONSENSUS FORECAST. TO THE W...AN AMPLIFIED UPPER TROUGH FROM FAR EASTERN GULF OF MEXICO THROUGH WESTERN CUBA INTO THE NW CARIBBEAN IS SUPPORTING A SURFACE REFLECTION OVER THE CENTRAL BAHAMAS AND CENTRAL CUBA. THE TROUGH IS EXPECTED TO MOVE W THROUGH THE FL STRAITS MON. SEE SECTION ABOVE FOR DETAILS. TROPICAL ATLC AND CARIBBEAN...ASCAT PASSES FROM 0126 UTC AND 0306 UTC AS WELL AS QUIKSCAT PASS FROM 2338 UTC SHOW 20 TO 25 KT WINDS S OF 16N BETWEEN 67W AND 74W AHEAD OF THE TROPICAL WAVE ALONG 62W. STRONG WINDS WILL SHIFT W WITH THE WAVE THROUGH MON NIGHT...WITH WINDS AND SEAS DECREASING A BIT IN THE REPRIEVE BETWEEN TROPICAL WAVES TUE. LOW PRES STILL ANALYZED AT 15N ON TROPICAL WAVE ALONG 45W AND SUPPORTED BY 2346 UTC ASCAT PASS...BUT EXPECT LOW TO FIZZLE OUT AS WAVE MOVES W TO ALONG 55W MON AND TO ALONG 65W WED. THE SAME ASCAT PASS SHOWS 20-25 KT WINDS WITHIN 300 NM N QUADRANT OF LOW PRES ON TROPICAL WAVE E OF AREA ALONG 32W. GFS IS A STRONG AND NORTHERLY OUTLIER WITH THIS SYSTEM BY EARLY NEXT WEEK. FORECAST RELIES MORE HEAVILY ON THE SOUTHERLY MODEL CONSENSUS WHICH DOES NOT ALLOW FOR AS TIGHT A PRES GRADIENT AS SEEN IN THE GFS. WARNINGS ATLC... .NONE. CARIBBEAN... .NONE. GULF OF MEXICO... .NONE $$ FORECASTER SCHAUER CLARK