000 AGXX40 KNHC 131844 MIMATS MARINE WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 245 PM EDT SUN SEP 13 2009 GULF OF MEXICO...A STATIONARY FRONT LIES FROM APALACHICOLA BAY TO A 1005 MB LOW PRES SYSTEM NEAR GALVESTON...TX AT 29N95W. A TROUGH EXTENDS S OF THE LOW TO 26N93W AND TO 20N96W. STRONGEST WINDS...TO 20 KT ACCORDING TO BUOY REPORTS...LIE E OF THE TROUGH TO 88W N OF 25N. SCATTERED MODERATE CONVECTION IS PLENTIFUL OVER THE CENTRAL GULF COAST AND S ALONG THE TROUGH TO 22N. THESE SHOWERS AND THUNDERSTORMS ARE BEING FUELED BY THE DEEP-LAYER MOIST SOUTHERLY FLOW ON THE EASTERN SIDE OF DEEP LAYERED LOW OVER TX...THE IMPETUS FOR THE SURFACE LOW IN THE NW GULF. MEAN TROUGHING OVER THE NW GULF AND RIDGING OVER THE SE GULF SHOULD PERSIST THROUGH THE FORECAST PERIOD. HOWEVER...THE DEEP LAYERED LOW OVER TX SHOULD DRIFT NE AS A COLD FRONT MOVES IN MON AND THE UPPER LEVEL TROUGH SUPPORTING THIS LOW TURNS NEGATIVE TILT. THIS WILL SHIFT THE PLENTIFUL SHOWER ACTIVITY EASTWARD IN THE NORTHERN GULF TUE THROUGH THU. THE GFS CONTINUES TO BE FASTER THAN THE MODEL CONSENSUS TO CARRY THE ANCHOR SURFACE LOW NE THROUGH THE LOWER MISSISSIPPI VALLEY...SO A SLOWER FRONTAL SOLUTION THAN THE GFS WAS USED FOR THE FORECAST. SW N ATLC...A 1011 MB LOW PRES LIES NEAR 31N78W WITH A STATIONARY FRONT EXTENDING SW TO JACKSONVILLE...FL. THIS LOW IS SUPPORTED BY SHORTWAVE ENERGY CURRENTLY MOVING E THROUGH N FL/S GA AS RIDGING BUILDS OVER THE SE GULF OF MEXICO. THIS ENERGY WILL TURN SOUTHEASTWARD TONIGHT. AT THE SAME TIME...NORTHERN STREAM TROUGHING OVER THE WESTERN N ATLC WILL AMPLIFY...TURNING THE STATIONARY BOUNDARY INTO A COLD FRONT. THE MODELS ARE IN REASONABLE AGREEMENT ON A FORECAST THAT TAKES THE SURFACE WAVE FROM OFF N FL ON A SE TRACK ALONG THE STRENGTHENING BAROCLINIC BOUNDARY THROUGH MON. THE FORECAST IS MORE UNCERTAIN FROM TUE ONWARD WITH THE MODELS GENERALLY AGREEING ON RIDGING BUILDING S OF THE LOW...LIFTING IT NORTHWARD OUT OF THE AREA AND FORCING ANY RESIDUAL TROUGHING W INTO FL BY THU. CARIBBEAN...AT 1200 UTC SHIP PHCQ REPORTED E WINDS TO 20 KT ALONG THE COAST OF COLOMBIA...BUT THESE WINDS IN THE CENTRAL CARIBBEAN HAVE SINCE DIMINISHED AS THE HIGH PRES NEAR 26N60W WEAKENS. STRONGER WINDS ARE FOUND IN THE NW CARIBBEAN WHERE SE FLOW IS STEERED BETWEEN HIGH PRES OVER THE SE GULF OF MEXICO AND LOW PRES OVER THE WESTERN GULF...MAINTAINING SE WINDS TO 20 KT OVER FAR NORTHWESTERN WATERS THROUGH MON. THE 1454 UTC ASCAT PASS SHOWS 20 TO 25 KT WINDS W OF 85W AND THIS IS CONFIRMED BY BUOY 42056 NEAR 20N85W AND SHIP A8IP2 NEAR 17N85W. BY TUE...WINDS UNDER 20 KT AND SEAS 5 FT OR LESS ARE EXPECTED OVER THE ENTIRE CARIBBEAN...WITH THE EXCEPTION OF WITHIN 90 NM OF THE COAST OF COLOMBIA WHERE WINDS MAY PULSE ABOVE 20 KT MOST LIKELY IN THE EARLY MORNING HOURS AND ESPECIALLY ON TUE IN THE WAKE OF THE TROPICAL WAVE CURRENTLY ALONG 61W. EXPECT THIS WAVE TO MOVE W OF THE CARIBBEAN ON THU WITH LITTLE FANFARE DURING ITS PASSAGE. TROPICAL N ATLC...WEAK TRADES OF 15 KT OR LESS AND SEAS OF 4 TO 7 FT WILL PERSIST THROUGH THE PERIOD IN THE TROPICAL N ATLC ZONE. NORTH SWELL WITH A PERIOD NEAR 10 SECONDS HAS BEGUN TO RAISE SIGNIFICANT WAVE HEIGHTS OVER NE WATERS TO 7 FT. THIS SWELL WILL TRAVEL SOUTH THROUGH THE ENTIRE ZONE BY TUE MORNING. FINALLY...MOST OF THE MODELS CARRY THE REMNANTS OF FRED WESTWARD PAST 50W BY WED MORNING AND THROUGH THE N PORTION OF THE ZONE BY THE END OF THE FORECAST PERIOD THU. THE REMNANT LOW OF FRED WILL APPROACH THE BUILDING RIDGE AXIS TO ITS NE ON MON AND THE EASTERLY WINDS ON THE NORTHERN SIDE OF THE REMNANT LOW ARE EXPECTED TO EXPAND UNDER THE TIGHT PRES GRADIENT. WARNINGS ATLC... .NONE. CARIBBEAN... .NONE. GULF OF MEXICO... .NONE $$ FORECASTER SCHAUER CLARK