000 AXNT20 KNHC 281118 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 705 AM EST SAT NOV 28 2009 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...METEOROLOGICAL ANALYSIS...WEATHER OBSERVATIONS...AND RADAR. BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1000 UTC. ...ITCZ... THE ITCZ AXIS IS CENTERED ALONG 9N12W 7N22W 4N34W 5N53W. ISOLATED MODERATE/STRONG CONVECTION IS FROM 4N-7N BETWEEN 9W-18W. SCATTERED MODERATE/STRONG CONVECTION IS WITHIN 90 NM OF THE AXIS BETWEEN 26W-39W. ...DISCUSSION... GULF OF MEXICO... SURFACE HIGH PRESSURE CONTINUES TO DOMINATE THE GULF OF MEXICO THIS MORNING ANCHORED BY A 1022 MB HIGH OFF THE COAST OF LOUISIANA NEAR 28N92W. THIS AREA OF HIGH PRESSURE BRINGS GENERALLY FAIR WEATHER ACROSS MUCH OF THE BASIN. HOWEVER...MOIST SWLY AND DIFFLUENT FLOW ALOFT BETWEEN A SHORTWAVE UPPER TROUGH OVER TEXAS AND AN UPPER LEVEL RIDGE COVERING THE GULF ARE SUPPORTING SCATTERED SHOWERS ACROSS THE NW GULF FROM 24N-31N BETWEEN 91W-95W...AS NOTED ON RADAR IMAGERY. LIGHT TO GENTLE SURFACE WINDS ARE ACROSS THE AREA. EXPECT THE SURFACE RIDGE TO SHIFT EWD AS SLY RETURN FLOW INCREASES OVER THE WRN GULF AHEAD OF THE NEXT COLD FRONT FORECAST TO MOVE OFF THE TEXAS COAST EARLY MON. CARIBBEAN SEA... AS OF 0900 UTC...A STATIONARY FRONT EXTENDS ACROSS THE NW CARIBBEAN FROM E CUBA NEAR 20N75W TO NW OF JAMAICA NEAR 19N79W CONTINUING ALONG 18N82W TO CENTRAL HONDURAS NEAR 14N87W. ISOLATED SHOWERS ARE ALONG THE FRONT AXIS...WITH SCATTERED SHOWERS NW OF THE FRONT FROM 17N-19N BETWEEN 80W-85W. SCATTERED SHOWERS/THUNDERSTORMS ARE ACROSS THE SW CARIBBEAN S OF 10N BETWEEN 74W-80W DUE TO SURFACE CONVERGENCE NEAR THE E PACIFIC ITCZ...AND A 1007 MB LOW OVER COLOMBIA NEAR 8N76W. THE ACTIVITY IS ALSO ENHANCED BY DIFFLUENT FLOW ALOFT BETWEEN AN UPPER LEVEL TROUGH IN THE E PACIFIC AND AN UPPER LEVEL RIDGE COVERING THE CARIBBEAN. THE REMAINDER OF THE CARIBBEAN IS EXPERIENCING GENERALLY FAIR WEATHER UNDER THE INFLUENCE OF DRY AND SUBSIDENT AIR ALOFT ASSOCIATED WITH THE AFOREMENTIONED UPPER LEVEL RIDGE COVERING THE ENTIRE BASIN WITH AXIS ALONG 75W. NE SURFACE WINDS OF 15-20 KT ARE NW OF THE FRONT...WITH FRESH TO STRONG ELY TRADEWINDS COVERING THE REMAINDER OF THE BASIN. EXPECT THE FRONT TO REMAIN STATIONARY AND BECOME DIFFUSE BY LATER TONIGHT WITH SHOWER ACTIVITY CONTINUING ALONG THE FRONT AXIS. ATLANTIC OCEAN... A COLD FRONT EXTENDS ACROSS THE W ATLC ENTERING THE DISCUSSION AREA E OF BERMUDA NEAR 32N61W CONTINUING ALONG 25N66W TO THE FAR SE BAHAMAS NEAR 21N71W TO E CUBA NEAR 20N75W BECOMING STATIONARY ACROSS THE CARIBBEAN. A PRE-FRONTAL SURFACE TROUGH IS AHEAD OF THE FRONT FROM 27N62W TO 20N69W. ISOLATED SHOWERS ARE ALONG THE FRONT AXIS...AND WITHIN 100 NM AHEAD OF THE TROUGH AXIS. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE E OF THE AXIS N OF 27N BETWEEN 55W-60W. THE FRONT IS SUPPORTED BY AN UPPER LEVEL TROUGH OVER THE WRN ATLC WITH AXIS EXTENDING FROM AN UPPER LEVEL LOW S OF MAINE TO E OF THE SE BAHAMAS. DIFFLUENT FLOW ALOFT BETWEEN THIS UPPER LEVEL TROUGH AND AN UPPER LEVEL RIDGE EXTENDING FROM THE CARIBBEAN ACROSS PUERTO RICO TO NEAR 33N52W IS SUPPORTING THE SHOWER ACTIVITY E OF THE FRONT. ACROSS THE CENTRAL ATLC...A NARROW UPPER LEVEL TROUGH WITH AXIS ALONG 49W IS SUPPORTING SCATTERED SHOWERS/THUNDERSTORMS FROM 18N-31N BETWEEN 44W-49W...AND FROM 16N-18N BETWEEN 49W-52W. THE UPPER TROUGH ALSO SUPPORTS A PAIR OF SURFACE TROUGHS MADE EVIDENT BY SE-NE WIND SHIFTS IN ASCAT SCATTEROMETER DATA. THE FIRST IS E OF THE LESSER ANTILLES EXTENDING FROM 17N54W TO 12N55W. THE SECOND IS TO THE N EXTENDING FROM 25N51W TO 20N53W. THE AFOREMENTIONED SHOWER ACTIVITY LIES TO THE E OF THESE TROUGHS MORE ASSOCIATED WITH THE UPPER DIFFLUENT ZONE. THE REMAINDER OF THE E ATLC IS DOMINATED BY A BROAD SURFACE RIDGE ANCHORED BY A 1027 MB AZORES HIGH N OF THE DISCUSSION AREA NEAR 38N31W. $$ WALTON