000 AXNT20 KNHC 031755 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT SUN SEP 03 2006 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHEASTERN SECTIONS OF SOUTH AMERICA...AND THE 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...SPECIAL FEATURES... AN ATLANTIC OCEAN 1008 MB LOW PRESSURE CENTER IS NEAR 13.3N 38.7W OR ABOUT 1500 MILES EAST OF THE LESSER ANTILLES. SCATTERED MODERATE TO STRONG CONVECTION IS FROM 11.5N-16N BETWEEN 37W AND 43W. THIS LOW IS GETTING BETTER ORGANIZED AS IT MOVES NWWD AT ABOUT 10 TO 15 MPH OVER THE WARM OCEAN WATERS. IF THE CURRENT DEVELOPMENT TREND CONTINUES...ADVISORIES ON THIS SYSTEM WILL BE INITIATED THIS AFTERNOON. ...TROPICAL WAVES... AN ATLANTIC OCEAN TROPICAL WAVE IS MOVING ACROSS THE CAPE VERDE ISLANDS. ITS AXIS IS ALONG 23/24W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS ASSOCIATED WITH THE WAVE FROM 11.5N-16N BETWEEN 22W-29W. ACCORDING TO SATELLITE PICTURES AND SURFACE DATA...A NEW TROPICAL WAVE WILL BE ADDED TO THE 18 UTC MAP ALONG 58/59W SOUTH OF 17N. AN INVERTED V-SHAPE PATTERN IS SEEN ON VIS SATELLITE IMAGERY. SCATTERED MODERATE CONVECTION IS FOUND JUST BEHIND THE WAVE AXIS. THIS SYSTEM IS EXPECTED TO MOVE ACROSS THE LESSER ANTILLES TOMORROW MORNING...INCREASING THE CHANCE OF RAIN. A CARIBBEAN SEA TROPICAL WAVE EXTENDS FROM THE MONA PASSAGE TO THE ABC ISLANDS ALONG 68W SOUTH OF 20N MOVING WEST 10 TO 15 KT. THIS TROPICAL WAVE ALSO SHOWS AN INVERTED V CLOUD PATTERN WITH SCATTERED MODERATE CONVECTION FROM 13N-17N BETWEEN 65W-70W. MOISTURE BEHIND THE WAVE WILL COMBINE WITH THE LOCAL ISLAND EFFECTS TO ENHANCE THE AFTERNOON SHOWER AND TSTMS ACTIVITY OVER PUERTO RICO AND THE SURROUNDING COASTAL WATERS. UPPER-LEVEL WINDS ARE NOT FAVORABLE FOR SIGNIFICANT DEVELOPMENT OF THIS SYSTEM. ...THE ITCZ... THE ITCZ AXIS IS CENTERED ALONG 15N17W 14N35W 11N46W 9N60W. OUTSIDE THE CONVECTIVE ACTIVITY ASSOCIATED WITH THE LOW PRESSURE CENTER AND THE TROPICAL WAVE NEAR THE CAPE VERDE ISLANDS...THERE ARE ONLY ISOLATED SHOWERS AND TSTMS. ...DISCUSSION... THE GULF OF MEXICO... NARROW UPPER LEVEL TROUGH EXTENDS FROM NE GEORGIA INTO THE NORTH-CENTRAL GULF NEAR 27N90W TO THE SW GULF AND THE MEXICO COAST JUST SOUTH OF TAMPICO. AN UPPER LOW IS OVER CENTRAL MEXICO. ABUNDANT UPPER LEVEL MOISTURE IS EAST OF THE TROUGH AXIS WHILE VERY DRY CONTINENTAL AIR IS KEEPING THE NW GULF CLOUD AND SHOWER FREE W OF THE UPPER TROUGH AXIS. A BROAD UPPER HIGH ASSOCIATED WITH TROPICAL STORM JOHN COVERS THE NORTH-CENTRAL PORTION OF MEXICO AND TEXAS. THE UPPER LEVEL MOISTURE FROM TROPICAL STORM JOHN...WHICH IS OVER THE CENTRAL BAJA CALIFORNIA IS SPREADING NEWD ACROSS THE SOUTHWESTERN UNITED STATES. AN UPPER HIGH IS OVER THE YUCATAN PENINSULA COVERING CENTRAL AMERICA...THE NW CARIBBEAN AND WESTERN CUBA. A SURFACE TROUGH IS ALONG 27N95W 23N96W INTO THE BAY OF CAMPECHE. ISOLATED MODERATE CONVECTION IS OVER THE GULF SOUTH OF A LINE FROM 22N97W TO 28N83W. THE CARIBBEAN SEA... A BROAD MID/UPPER LEVEL TROUGH RUNS FROM AN UPPER LOW LOCATED NEAR 25N72W ACROSS EASTERN CUBA AND JAMAICA INTO THE CENTRAL CARIBBEAN. AN UPPER HIGH COVERS THE EASTERN CARIBBEAN E OF 70W. A DIFFLUENT PATTERN ALOFT IS GENERATING CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION NORTH OF 18N W OF 75W OVER JAMAICA...CUBA...THE BAHAMAS AND SOUTH FLORIDA. ONE OF THESE CLUSTERS IS OVER THE ISLE OF YOUTH. SIMILAR CONVECTION IS OVER THE SW CARIBBEAN...AFFECTING THE CARIBBEAN PLAINS OF COSTA RICA DUE TO THE CLOSE PROXIMITY OF THE ITCZ AXIS. A TROPICAL WAVE IS PRODUCING SHOWER AND TSTM ACTIVITY OVER THE EASTERN CARIBBEAN... MAINLY SOUTH OF PUERTO RICO AND DOMINICAN REPUBLIC. THIS FEATURE IS ALSO BRINGING WINDS OF 15-20 KT OVER THE NE CARIBBEAN. MODERATE TO FRESH TRADE WINDS WILL CONTINUE OVER THE CENTRAL CARIBBEAN THROUGH MONDAY NIGHT. TYPICAL STREAMERS OR LINE CLOUDS ARE FORMING DOWNSTREAM OVER THE EASTERN CARIBBEAN. THE ATLANTIC OCEAN... AN UPPER LOW IS OVER THE W ATLC NEAR 25N72W AND LIES SOUTH OF AN UPPER RIDGE THAT EXTENDS FROM THE CAROLINA COASTS EWD AND SEWD TO NEAR 27N58W. EAST OF THE RIDGE THERE IS AN UPPER TROUGH THAT RUNS FROM 31N37W TO 17N50W. THE ASSOCIATED COLD FRONT ENTERS THE AREA NEAR 31N43W AND CONTINUES MAINLY WWD TO 29N62W. SCATTERED MODERATE CONVECTION IS WITHIN AROUND 100 NM AHEAD OF THE FRONT. A STATIONARY FRONT GOES FROM 29N62W TO BEYOND BERMUDA. AN UPPER RIDGE COVERS THE REMAINDER OF THE ATLC AND WESTERN AFRICA. A SURFACE RIDGE EXTENDS FROM A 1023 MB HIGH LOCATED NE OF THE AZORES ACROSS THE E ATLC. THIS FEATURE IS KEEPING THIS AREA MOSTLY DRY AND CLEAR. VIS SATELLITE PICTURES AND THE SAHARAN AIR LAYER FROM UW-CIMSS SHOW A BROAD AREA OF AFRICAN DUST COVERING A GOOD PORTION OF THE ATLC OCEAN BETWEEN THE COLD FRONT AND THE LOW PRESSURE CENTER MENTIONED ABOVE. THE LEADING EDGE OF THE DUST IS REACHING THE LEEWARD ISLANDS. $$ GR