000 AXNT20 KNHC 282348 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT TUE AUG 28 2007 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN 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...METEOROLOGICAL ANALYSIS... WEATHER OBSERVATIONS...AND RADAR. BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...TROPICAL WAVES... A TROPICAL WAVE IS ALONG 20W S OF 21N MOVING W AT 10-15 KT. SATELLITE IMAGERY SHOWS A BROAD AREA OF CYCLONIC TURNING ASSOCIATED WITH THIS WAVE IN THE VICINITY OF THE CAPE VERDE ISLANDS. 850 MB MODEL GUIDANCE SUGGEST A STRONG VORTICITY MAXIMUM IMPLYING A LOW WITHIN THIS AREA. WIDELY SCATTERED MODERATE CONVECTION IS FROM 10N-16N EAST OF 22W. A QUIKSCAT PASS FROM AROUND 2000 UTC ALSO SHOWED A CYCLONIC CIRCULATION NEAR 12N22W. A TROPICAL WAVE IS LOCATED MIDWAY BETWEEN AFRICA AND THE LESSER ANTILLES ALONG 40W/41W S OF 18N. A 1010 MB LOW IS ALONG THE WAVE AXIS NEAR 10N. SHOWERS AND THUNDERSTORMS ASSOCIATED WITH THIS FEATURE HAVE NOT BECOME ANY BETTER ORGANIZED THIS EVENING. HOWEVER...ENVIRONMENTAL CONDITIONS ARE EXPECTED TO GRADUALLY BECOME MORE FAVORABLE FOR SOME DEVELOPMENT AS THIS SYSTEM MOVES WESTWARD AT 15 TO 20 MPH. THIS TROPICAL WAVE WILL ENTER THE TROPICAL N ATLC WED NIGHT OR THU...AND INTO THE E CARIBBEAN FRI AND SAT. A TROPICAL WAVE IS OVER THE EASTERN CARIBBEAN ALONG 65W S OF 21N MOVING W 10-15 KT. AN INVERTED-V LOW LEVEL CLOUD SIGNATURE IS SEEN ON VIS SATELLITE PICTURES. THE WAVE IS ENHANCING SOME SHOWER ACTIVITY ACROSS PUERTO RICO...THE VIRGIN ISLANDS AND THE COASTAL WATERS. THIS WAVE WILL CONTINUE TO MOVE WESTWARD ACROSS PUERTO RICO THIS EVENING AND TONIGHT...REACHING DOMINICAN REPUBLIC EARLY WED MORNING. A STRONG TROPICAL WAVE IS OVER THE WESTERN CARIBBEAN ALONG 85W S OF 22N. DISORGANIZED SHOWERS AND THUNDERSTORMS EXTENDING FROM HONDURAS NORTHEASTWARD TO THE CAYMAN ISLANDS ARE ASSOCIATED WITH THIS TROPICAL WAVE. DEVELOPMENT OF THIS SYSTEM IS NOT EXPECTED DUE TO PROXIMITY TO LAND. HOWEVER...LOCALLY HEAVY RAINFALL IS POSSIBLE OVER PORTIONS OF CENTRAL AMERICA AND THE YUCATAN PENINSULA DURING THE NEXT DAY OR SO AS THIS SYSTEM CONTINUES WESTWARD AT 10 TO 15 KT. THE WAVE IS ALSO HELPING TO INDUCE SCATTERED SHOWERS AND TSTMS OVER WESTERN CUBA. TROPICAL WAVE IS ALONG 94W S OF 21N MOVING SLOWLY WWD. CONVECTION IS NOTED ON THE SOUTHERN PORTION OF THE WAVE THAT EXTENDS INTO THE EPAC REGION. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 12N16W 8N30W 9N45W 8N60W. IN ADDITION TO CONVECTION ASSOCIATED WITH THE TROPICAL WAVE... CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE WITHIN 80 NM EITHER SIDE OF AXIS BETWEEN 21W AND 36W. SIMILAR CONVECTION IS OVER NORTHERN SURINAME AND PARTS OF GUYANA. DISCUSSION... GULF OF MEXICO... BROAD UPPER RIDGE DOMINATES THE WESTERN HALF OF THE GULF PRODUCING UPPER NELY WINDS. AN UPPER HIGH IS INLAND OVER SOUTH GEORGIA COVERING THE NE GULF AND THE STATE OF FLORIDA. UPPER DIFFLUENCE ASSOCIATED WITH THESE FEATURES IS SUPPORTING THE DEVELOPMENT OF SCATTERED SHOWERS AND TSTMS OVER THE GULF WATERS MAINLY N OF 25N. AN INVERTED TROUGH IS OVER THE YUCATAN PENINSULA ENHANCING CONVECTION OVER THIS AREA AND CENTRAL AMERICA. A TROPICAL WAVE REMAINS OVER THE BAY OF CAMPECHE WITH NO SIGNIFICANT CONVECTION. A WEAK SFC RIDGE DOMINATES THE REGION WITH LIGHT WINDS. A SFC TROUGH IS ANALYZED ON THE 21Z MAP ALONG THE FAR WEST GULF N OF 21N. ISOLATED SHOWERS AND TSTMS ARE NEAR THE FLORIDA KEYS. A RIDGE WILL PERSIST ACROSS N GULF COAST THROUGH FRI. CARIBBEAN SEA... THE MAIN WEATHER FEATURE ACROSS THE AREA IS THE STRONG TROPICAL WAVE LOCATED OVER THE WESTERN CARIBBEAN. ANOTHER TROPICAL WAVE IS CROSSING PUERTO RICO. SEE THE TROPICAL SECTION. AN UPPER RIDGE DOMINATES MOST THE BASIN. AN UPPER TROUGH EXTENDS FROM AN UPPER LOW OVER THE ATLC ACROSS THE SE BAHAMAS AND E CUBA. TRADEWINDS ARE MOSTLY 10-15 KT WITH SOME 20 KT WINDS ALONG THE COAST OF COLOMBIA. SCATTRED MODERATE CONVECTION IS OBSERVED OVER NORTHERN VENEZUELA AND COLOMBIA DUE TO THE PRESENCE OF THE ITCZ. ATLANTIC OCEAN... THE UPPER HIGH SITUATED OVER S GEORGIA EXTENDS A RIDGE OVER THE W ATLC...THE NW AND CENTRAL BAHAMAS AND FLORIDA. FURTHER EAST THERE IS AN UPPER LOW WITH A TROUGH EXTENDING SW ACROSS THE SE BAHAMAS AND E CUBA. A BROAD UPPER HIGH REMAINS OVER THE CENTRAL ATLC NEAR 22N53W WITH DRY STABLE AIR COVERING THE ATLC E OF 55W. THIS HIGH EXTENDS A RIDGE INTO THE NE CARIBBEAN. ANOTHER UPPER RIDGE DOMINATES WESTERN AFRICA AND THE E ATLC. AT THE SURFACE... FROM WEST TO EAST...THERE IS A WEAK TROUGH ALONG 30N68W 25N71W GENERATING ISOLATED SHOWERS AND TSTMS. A WEAK 1020 MB HIGH IS NEAR 27N54W. THIS SYSTEM IS FORECAST TO DISSIPATE AND ANOTHER 1024 MB HIGH LOCATED NORTH OF THE AREA WILL TAKE CONTROL OF THE WEST-CENTRAL ATLC. A COLD FRONT IS ENTERING THE FORECAST AREA ALONG 30N BETWEEN 40W AND 50W. A WEAK RIDGE COVERS THE REMAINDER OF THE ATLANTIC OCEAN PRODUCING FAIR WEATHER CLOUDS WITH LIGHT TO MODERATE TRADE WINDS. AN AREA OF DISORGANIZED SHOWERS AND THUNDERSTORMS IS LOCATED JUST N OF OUR FORECAST AREA NEAR THE CAROLINAS. THIS ACTIVITY IS ASSOCIATED WITH A NON-TROPICAL AREA OF LOW PRESSURE. WHILE ENVIRONMENTAL CONDITIONS ARE NOT CURRENTLY FAVORABLE FOR DEVELOPMENT...THEY COULD BECOME MORE FAVORABLE OVER THE NEXT COUPLE OF DAYS. $$ GR