000 AXNT20 KNHC 282340 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT SAT JUN 28 2008 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...TROPICAL WAVES... A TROPICAL WAVE IS ALONG 29W S OF 14N MOVING W NEAR 15 KT. THE WAVE REMAINS EMBEDDED WITHIN THE ITCZ WITH LITTLE SIGNIFICANT DEEP CONVECTION. ONLY A SMALL CLUSTER OF SCATTERED SHOWERS IS FROM 9N-10N BETWEEN 27W AND THE WAVE AXIS. A TROPICAL WAVE IS ALONG 38W/39W S OF 14N MOVING W NEAR 15 KT. A BROAD AREA OF LOW-MID LEVEL CIRCULATION IS EVIDENT ON SATELLITE IMAGERY FROM 7N-12N BETWEEN 33W-40W. SCATTERED MODERATE CONVECTION IS ALSO SEEN IN THIS REGION. A TROPICAL WAVE IS ALONG 54W S OF 12N MOVING W 15-20 KT. A LOW-AMPLITUDE INVERTED-V SIGNATURE IS OBSERVED ON VISIBLE SATELLITE IMAGERY. NO SIGNIFICANT CONVECTION IS ASSOCIATED WITH THIS WAVE. A WEAK TROPICAL WAVE IS IN THE CENTRAL CARIBBEAN ALONG 69W FROM THE DOMINICAN REPUBLIC TO VENEZUELA. SWLY FLOW AND DIVERGENCE ALOFT IS ENHANCING SCATTERED MODERATE CONVECTION EAST OF THE WAVE AXIS AND OVER THE EASTERN CARIBBEAN ISLANDS. A TROPICAL WAVE IS IN THE FAR SW POTION OF THE BAY OF CAMPECHE ALONG 96W/97W S OF 21N. THE NORTHERN PORTION OF THE WAVE IS BEGINNING TO DISPERSE UNDER STRONG SHEAR ALOFT. ASSOCIATED CONVECTION NOW LIES MAINLY OVER THE E PACIFIC...HOWEVER...A CLUSTER OF SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS IS ALONG THE COAST OF MEXICO FROM 19N-23N. PLEASE SEE THE EASTERN PACIFIC TROPICAL WEATHER DISCUSSION...TWDEP...FOR FURTHER DETAILS ON THIS WAVE. ...ITCZ... THE ITCZ AXIS IS CENTERED ALONG 12N15W 10N25W 7N35W 4N45W 8N55W AND INTO S AMERICA NEAR 8N60W. IN ADDITION TO CONVECTION ASSOCIATED WITH TROPICAL WAVES...SCATTERED MODERATE TO STRONG CONVECTION IS MOVING OFF THE WEST AFRICAN COAST TO 20W FROM 9N-12N. SCATTERED MODERATE CONVECTION IS FROM 6N-8N BETWEEN 24W-26W. SIMILAR CONVECTION IS WITHIN 90 NM S OF THE AXIS BETWEEN 40W-45W. ...DISCUSSION... GULF OF MEXICO... AN UPPER-LEVEL LOW IS SITUATED OFF THE S TEXAS COAST COVERING THE WESTERN GULF THIS EVENING. AN UPPER HIGH OVER THE CARIBBEAN EXTENDS A RIDGE OVER THE CENTRAL AND EASTERN GULF. SOUTHERLY FLOW BETWEEN THESE UPPER FEATURES IS ADVECTING A DEEP LAYER OF TROPICAL MOISTURE FROM THE E PACIFIC INTO THE REGION. THE DIFFLUENT PATTERN OF THIS FLOW IS ENHANCING SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS IN THE WESTERN AND CENTRAL GULF WITHIN 200 NM OF THE COASTLINE BETWEEN THE TEXAS/MEXICO BORDER AND THE MISSISSIPPI/ALABAMA BORDER. DAYTIME HEATING-INDUCED THUNDERSTORMS ARE ALONG THE GULF COAST OF FLORIDA...THE FLORIDA KEYS...AND THE NW COAST OF CUBA. THIS ACTIVITY WILL DECREASE AFTER SUNSET. A SECOND AREA OF CONVECTIVE ACTIVITY IS IN THE BAY OF CAMPECHE AND IS ASSOCIATED WITH A TROPICAL WAVE. EXPECT THIS ACTIVITY TO DIMINISH AS THE WAVE EXITS THE GULF LATER TONIGHT. AT THE SFC...A HIGH PRESSURE RIDGE EXTENDS FROM THE CENTRAL ATLC OVER FLORIDA AND ACROSS THE GULF MAINTAINING S-SE 15-20 KT RETURN FLOW OVER THE SOUTH-CENTRAL AND WESTERN PORTIONS OF THE GULF. CARIBBEAN... AN UPPER-LEVEL RIDGE/TROUGH/RIDGE PATTERN COVERS THE CARIBBEAN. DIVERGENCE ALONG THE SOUTHERN EXTENT OF THE RIDGE OVER THE NW CARIBBEAN COUPLED WITH LOW-LEVEL WIND SPEED CONVERGENCE IS GENERATING SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WITHIN 100 NM OF THE COASTS OF PANAMA AND COSTA RICA. OROGRAPHIC AND HEATING-INDUCED THUNDERSTORMS ARE ALONG THE COAST OF CUBA AND JAMAICA AND WILL WEAKEN POST SUNSET. STRONG SUBSIDENCE ALONG THE BASE OF THE UPPER TROUGH IS INHIBITING DEEP CONVECTION IN THE CARIBBEAN BETWEEN 71W-83W. DIVERGENT FLOW ALONG THE LEADING EDGE OF THE TROUGH IS ENHANCING CONVECTION ASSOCIATED WITH THE TROPICAL WAVE ALONG 69W AND INDUCING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS OVER THE EASTERN CARIBBEAN AND LESSER ANTILLES. A STRONG SFC RIDGE OVER THE CENTRAL ATLANTIC CONTINUES TO MAINTAIN STRONG TRADES THROUGHOUT THE CARIBBEAN. ATLANTIC... UPPER-LEVEL DIVERGENCE IS GENERATING AN AREA OF SCATTERED SHOWERS AND THUNDERSTORMS IN THE W ATLC BETWEEN THE BAHAMAS AND 32N W OF 71W. SWLY FLOW BETWEEN AN UPPER TROUGH OVER THE W ATLC AND AN UPPER RIDGE EAST OF THE WINDWARD ISLANDS IS ADVECTING DEEP-LAYER MOISTURE INTO THE TROPICAL N ATLC W OF 54W. THE REMAINDER OF THE DISCUSSION AREA IS DOMINATED BY A VERY STABLE SFC RIDGE ANCHORED BY A STATIONARY 1031 MB HIGH PRESSURE SW OF THE AZORES. THIS RIDGE IS MAINTAINING MODERATE EASTERLY FLOW THROUGHOUT THE REGION. ALOFT...UPPER DIVERGENCE IS ENHANCING CONVECTION ALONG THE ITCZ. $$ WADDINGTON