000 AXNT20 KNHC 042339 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 705 PM EST SUN NOV 04 2012 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS OF SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN COAST FROM THE EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED ON SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL ANALYSIS. BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE E TROPICAL ATLC NEAR 13N16W TO 11N19W WHERE THE ITCZ BEGINS AND CONTINUES TO 6N30W TO 6N40W TO NE VENEZUELA NEAR 9N60W. SCATTERED MODERATE CONVECTION IS FROM 3N-10N BETWEEN 10W-37W. SIMILAR CONVECTION IS WITHIN 120 NM N OF ITCZ AXIS BETWEEN 48W AND 55W. ...DISCUSSION... GULF OF MEXICO... A 1020 MB HIGH PRES IS CENTERED OVER THE NORTH-CENTRAL GULF OF MEXICO NEAR 27N88W. MULTILAYERED CLOUDS AND LIGHT TO GENTLE BREEZE ARE NOTED ACROSS THE AREA UNDER THE INFLUENCE OF THIS FEATURE. DOPPLER RADAR IMAGERY SHOWS SCATTERED SHOWERS OVER SE LOUISIANA AND S MISSISSIPPI. THIS SHOWER ACTIVITY IS OCCURRING AHEAD OF STATIONARY FRONT CURRENTLY EXTENDING OVER THE N GULF STATES. SOME SHOWER AND TSTMS ACTIVITY IS ALSO NOTED OVER SOUTH TEXAS. THE HIGH PRES WILL WEAKEN TONIGHT ALLOWING FOR A COLD FRONT TO RAPIDLY MOVE SE ACROSS THE GULF EARLY TUE THROUGH EARLY WED. EXPECT INCREASING WINDS AND BUILDING SEAS IN THE WAKE OF THE FRONT. IN THE UPPER LEVELS...MAINLY ZONAL FLOW PREVAILS WITH A BAND OF 70-80 KT WLY WINDS OVER THE N GULF AND ACROSS THE STATE OF FLORIDA. THESE WINDS ARE TRANSPORTING ABUNDANT MID TO UPPER LEVEL MOISTURE FROM THE EPAC ACROSS CENTRAL MEXICO INTO THE GULF REGION. CARIBBEAN SEA... HIGH PRES LOCATED N OF AREA IS PRODUCING MODERATE TO FRESH TRADE WINDS...WITH THE STRONGEST WINDS OF 20 KT OVER THE SOUTH-CENTRAL CARIBBEAN. SCATTEROMETER DATA CONFIRMED THE PRESENCE OF THESE WINDS. THE COLD THAT IS FORECAST TO MOVE ACROSS THE GULF OF MEXICO IS EXPECTED TO REACH THE YUCATAN CHANNEL BY EARLY WED...THEN WILL WEAKEN AS IT MOVES ACROSS CUBA AND THE NORTHERN CARIBBEAN. A SURGE OF 15-20 KT NLY WINDS IS EXPECTED ACROSS THE WESTERN CARIBBEAN IN THE WAKE OF THE FRONT BY WED...WHILE NE TO E WINDS WILL CONTINUE TO PREVAIL ACROSS THE REMAINDER OF THE BASIN. IN THE UPPER LEVELS...AN UPPER LEVEL HIGH IS CENTERED NEAR CABO GRACIAS A DIOS NICARAGUA. THIS HIGH COVERS THE MAJORITY OF THE CARIBBEAN SEA...CENTRAL AMERICA...SE MEXICO AND CUBA. UPPER DIFFLUENCE ASSOCIATED WITH THIS HIGH IS HELPING TO INDUCE SCATTERED SHOWERS AND TSTMS OVER PARTS OF HONDURAS AND NICARAGUA AS WELL AS SCATTERED SHOWERS AND ISOLATED TSTMS ACROSS THE NW CARIBBEAN. SHALLOW MOISTURE EMBEDDED IN THE TRADE WIND FLOW WILL MOVE ACROSS THE REMAINDER OF THE REGION PRODUCING ISOLATED TO SCATTERED PASSING SHOWERS. ATLANTIC OCEAN... A COLD FRONT ENTERS THE FORECAST REGION NEAR 31N60W THEN CONTINUES SW TO NEAR 26N69W. AN EARLIER OSCAT PASS SHOWED THE WIND SHIFT ASSOCIATED WITH THIS FRONT FORECAST TO DISSIPATE S OF 31N IN ABOUT 24 HOURS AS IT CONTINUES TO MOVE SE ACROSS THE ATLANTIC OCEAN. ANOTHER COLD FRONT IS EXPECTED TO MOVE ACROSS THE WATERS E OF FLORIDA LATE MON THROUGH TUE...REACHING WESTERN CUBA EARLY WED MORNING. A COOLER AND DRIER AIR MASS WILL FOLLOW THE FRONT. CURRENTLY...THE SAN JUAN DOPPLER RADAR SHOWS A BAND OF SHOWERS WITH EMBEDDED TSTMS N OF PUERTO RICO AND NEAR 20N. THIS ACTIVITY IS ASSOCIATED WITH AN OLD FRONTAL BOUNDARY LINGERING ACROSS THE AREA FOR SEVERAL DAYS. A SURFACE TROUGH IS ANALYZED ON THE 1800 UTC SURFACE MAP EXTENDING FROM 26N55W TO NE NE OF DOMINICAN REPUBLIC. A SHORT-WAVE TROUGH MOVING EWD ACROSS THIS REGION IS ALSO HELPING TO SUPPORT THIS CONVECTIVE ACTIVITY. FARTHER E...A 1010 MB LOW IS CENTERED OVER THE E ATLANTIC NEAR 31N26W. A SURFACE TROUGH EXTENDS S FROM THE LOW CENTER TO NEAR 23N30W. A WINDSAT PASS PROVIDED OBSERVATIONS OF FRESH TO STRONG WINDS BETWEEN THE LOW CENTER AND A HIGH PRES LOCATED WELL N OF AREA. A DEEP LAYER TROUGH WITH AXIS ALONG 25W SUPPORTS THIS LOW PRES SYSTEM. IN THE TROPICS...A SURFACE TROUGH EXTENDS FROM 15N36W TO 9N41W. SOME SHOWER ACTIVITY IS SEEN ON SATELLITE IMAGERY NEAR THE SOUTHERN END OF THE TROUGH AXIS. THIS TROUGH WILL DRIFT WWD DURING THE NEXT 24 HOURS. A RIDGE...AT THE SURFACE AND ALOFT DOMINATES THE REMAINDER OF THE ATLC OCEAN... PARTICULARLY BETWEEN 30W AND 60W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ GR