000 AXNT20 KNHC 202330 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT SUN MAR 20 2011 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTION 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...ITCZ... THE ITCZ AXIS EXTENDS FROM LIBERIA NEAR 6N10W TO EQ24W DEPICTING SWLY/WLY MONSOON FLOW CONVERGENCE. E OF 24W...THE ITCZ AXIS EXTENDS ALONG THE EQUATOR TO 35W CONTINUING TO 3N51W DEPICTING CONVENTIONAL CONVERGENT WIND FLOW. SCATTERED MODERATE TO STRONG CONVECTION IS FROM 2N-7N BETWEEN 11W-16W. SCATTERED MODERATE CONVECTION IS FROM 2N-3N BETWEEN 39W-44W. ...DISCUSSION... GULF OF MEXICO... HIGH PRES CONTINUES TO DOMINATE THE GULF OF MEXICO AS A STRONG RIDGE AXIS EXTENDS DOWN THE ERN UNITED STATES INTO NE FLORIDA ACROSS THE GULF TO THE BAY OF CAMPECHE. WATER VAPOR IMAGERY INDICATES DRY AIR SUBSIDENCE ACROSS THE BASIN SUPPORTING MOSTLY FAIR CONDITIONS ACROSS THE AREA WITH ONLY A FEW PATCHES OF LOW LEVEL CLOUDS. WINDS ARE LIGHT AND VARIABLE ACROSS THE NE GULF BECOMING ELY ACROSS THE SE GULF UP TO 15 KTS. WINDS ARE MAINLY SE IN RETURN FLOW OVER THE WRN GULF APPROACHING 20 KTS NEAR THE SE TEXAS COASTLINE. THE SURFACE RIDGE IS EXPECTED TO REMAIN STATIONARY AS A FRONTAL BOUNDARY DISSIPATES MAINTAINING FAIR CONDITIONS ACROSS THE BASIN FOR THE NEXT SEVERAL DAYS. CARIBBEAN SEA... THE CARIBBEAN IS UNDER THE INFLUENCE OF A DRY AND STABLE AIR MASS WHICH IS INHIBITING DEEP CONVECTION AND MAINTAINING MOSTLY FAIR CONDITIONS ACROSS THE BASIN. A FEW TRADE WIND SHOWERS ARE NOTED IN THE NELY FRESH TO STRONG TRADE WIND FLOW DOWNSTREAM FROM PUERTO RICO. SURFACE WINDS ALSO GAIN A CYCLONIC TENDENCY AROUND THE COAST OF COLOMBIA WITH WINDS REACHING 25 KT CAUSING OROGRAPHIC SHOWER ACTIVITY ALONG THE EAST COASTS OF COSTA RICA AND PANAMA. UPPER LEVEL RIDGING DOMINATES THE BASIN WHILE A DRY UPPER LEVEL TROUGH EXTENDS FROM THE W ATLC ACROSS CENTRAL CUBA TO HONDURAS. EXPECT LITTLE CHANGE OVER THE NEXT 24 TO 48 HOURS. ATLANTIC OCEAN... A COLD FRONT IS PUSHING FURTHER SOUTHWARD INTO THE W ATLC ALONG 31N59W TO 27N72W TO 28N78W THEN DISSIPATING E OF FLORIDA. THE FRONT IS SUPPORTED BY A LONGWAVE UPPER TROUGH BETWEEN 50W-75W. THE FRONT EXTENDS THROUGH A STRONG SURFACE RIDGE OVER THE ERN CONUS AND W ATLC. SCATTERED SHOWERS ARE FOUND ALONG THE FRONTAL BOUNDARY WITH ISOLATED SHOWERS UP TO 100 NM BEHIND THE FRONT. THE REMAINDER OF THE W ATLC IS EXPERIENCING FAIR WEATHER DUE TO DRY AIR ALOFT. A WEAKENING SHORTWAVE UPPER TROUGH IS IN THE CENTRAL ATLC ALONG 45W SUPPORTING A 1008 MB SURFACE LOW NEAR 28N50W. A SURFACE TROUGH EXTENDS SWD TO NEAR 22N51W. A SECOND SURFACE TROUGH EXTENDS FROM 22N49W TO 16N54W THEN CONTINUING AS A SHEAR LINE TO THE WINDWARD ISLANDS NEAR 13N61W. SCATTERED SHOWERS ARE WITHIN 150 NM E OF THE SURFACE TROUGH. RIDGING PREVAILS OVER THE REMAINDER OF THE FAR E ATLC...MAINTAINING FAIR CONDITIONS. ALOFT...MAINLY ZONAL WLY FLOW IS S OF 25N AROUND A BROAD UPPER RIDGE CENTERED OVER THE TROPICAL ATLC NEAR 4N42W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ MUNDELL