000 AGXX40 KNHC 200626 MIMATS MARINE WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 230 AM EDT SUN SEP 20 2009 GULF OF MEXICO... A NE TO SW RIDGE IS SETTING UP ACROSS THE NORTHERN GULF AND EXPECTED TO PERSIST THROUGH EARLY TUE...THEN THE RIDGE SHIFTS NE OF AREA ALLOWING A WEAKENING COLD FRONT TO MOVE OFFSHORE TX AND STALL ACROSS OVER THE N CENTRAL COASTAL PLAINS AND THE NW GULF WATERS TUE NIGHT AND WED...GRADUALLY DISSIPATING THU INTO FRI. FURTHER S...A BROAD INVERTED TROUGH WILL PERSIST OVER THE SOUTHERN WATERS THROUGH THE PERIOD. SW N ATLC... ALOFT...AN UPPER TROUGH IS BRUSHING THE NORTHERN PORTION AND AN UPPER CYCLONE JUST N OF PUERTO RICO IS MOVING W WITH TIME. SQUEEZED BETWEEN THESE FEATURES...A UPPER RIDGE AXIS EXTENDS ACROSS SE FL AND THE NW BAHAMAS ADVECTING IN UPPER MOISTURE FROM FORMER CONVECTION SW OF AREA. AT THE LOW LEVELS A TROUGH N OF 25N ALONG 70W IS EXPECTED TO MOVE NW REACHING THE NE FL COAST LATE TUE. THE NORTHERN EXTENSION OF A LOW LEVEL TROUGH IS OVER S FL WITH THE UPPER RIDGE SUPPORTING CONTINUED CONVECTION OVER THE FL STRAITS BUT E WINDS ARE LIGHT AND SEAS 1-3 FT. ATLC RIDGE WILL BUILD W ACROSS AREA IN WAKE OF TROUGH WED INTO FRI. SEAS ARE 4-6 FT E OF BAHAMAS AND SHOULD DIMINISH TO 3-4 FT BY LATE IN THE WEEK. CARIBBEAN AND TROPICAL N ATLC... AN UPPER CYCLONE OVER THE NW CARIBBEAN CONTINUES WESTWARD ENHANCING CONVECTION W OF 79W. NOT MUCH EFFECTS AT SURFACE WITH NE-E WINDS AT 5-10 KT AND SEAS 2-4 FT. A SECOND UPPER CYCLONE JUST N OF PUERTO RICO IS ENHANCING CONVECTION OVER THE NE CARIBBEAN. ELY TRADES AT 15-20 KT OVER THE DEEP TROPICS SHOULD PERSIST THROUGH THU...THEN RELAX SOME FRI. A TROPICAL LOW NEAR 14N45W IS EXPECTED TO MOVE NW JUST BRUSHING THE NE PORTION OF THE TROPICAL ATLC ZONE TUE NIGHT INTO WED. ALTHOUGH NHC HAS POSSIBILITY OF TROPICAL CYCLONE FORMATION AT 30-50 PERCENT OVER THE NEXT 48 HOURS...CONVECTION DECREASED CONSIDERABLY GOING INTO THIS MORNINGS GOES ECLIPSE. ALSO APPEARS TO BE A LOT OF SHEAR. JUST RELEASED LATEST GRAPHIC PACKAGE WITH POSSIBLE FORMATION WORDING...AND WILL CONTINUE IN UPCOMING HSF TEXT...BUT THIS MAY WORDING BE DROPPED LATER TODAY. CURRENTLY GRADIENT SUPPORTING 20-25 KT OVER THE NE QUADRANT OF LOW...BUT EXPECT THIS GRADIENT TO BACK OFF TO MOSTLY 20 KT EARLY THIS WEEK. CONDITIONS CONSIDERABLY LESS OVER THE W SEMICIRCLE WITH WINDS EXPECTED TO BE VARIABLE 5-10 KT SW OF THE LOW BUT MAY SEE SWELLS PUSHING SEAS TO ABOUT 7 FT NEAR NEAR 20N56W AS EARLY AS MON NIGHT. ATLC... .NONE. CARIBBEAN... .NONE. GULF OF MEXICO... .NONE $$ FORECASTER NELSON