000 AXNT20 KNHC 181100 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT FRI AUG 18 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1045 UTC. ...TROPICAL WAVES... AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 35W/36W SOUTH OF 21N MOVING WEST NEAR 10 KT. CYCLONIC TURNING OF LOW LEVEL CLOUDS IS NOTED N OF THE ITCZ. THE ONLY CONVECTION NEAR THIS WAVE IS SCATTERED MODERATE...IN THE VICINITY OF THE ITCZ...FROM 10N-13N BETWEEN 34W-39W. AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 51W/52W SOUTH OF 20N MOVING WEST NEAR 15 KT. AN INVERTED-V LOW LEVEL CLOUD SIGNATURE IS NOTED IN LAST NIGHTS SHORTWAVE IR IMAGERY AND FIRST COUPLE FRAMES OF THIS MORNINGS VISIBLE. SCATTERED SHOWERS AND TSTMS LIE NEAR THE NRN PORTION OF THE WAVE AXIS FROM 18N-23N BETWEEN 51W-56W...AS THE WAVE INTERACTS WITH THE UPPER LOW NEAR 23N63W. THE ONLY OTHER REGION OF CONVECTION NEAR THE WAVE IS CONFINED TO THE ITCZ WITH ISOLATED MODERATE CONVECTION FROM 6N-12N BETWEEN 45W-55W. A WESTERN CARIBBEAN SEA TROPICAL WAVE IS ALONG 85W SOUTH OF 22N MOVING WEST 10 TO 15 KT. VERY LITTLE CYCLONIC CURVATURE IS NOTED IN THE LOW CLOUD MOTIONS AND SURFACE OBSERVATIONS NEAR THIS WAVE AXIS...AND THE WAVE MAY NEED TO BE REPOSITIONED FURTHER WEST THROUGH THE EPAC ON THE 1200 UTC MAP DUE TO THE CYCLONIC SWIRL AND CONVECTION NOTED NEAR 10N90W. AT THE PRESENT LOCATION...ISOLATED SHOWERS AND TSTMS LIE WITHIN 150NM OF EITHER SIDE OF THE AXIS S OF 18N. THE CLUSTER OF MODERATE TO STRONG CONVECTION OFF THE CARIBBEAN COAST OF PANAMA AND COSTA RICA SEEMS MORE ASSOCIATED WITH THE ITCZ. ...THE ITCZ... ITCZ IS CENTERED ALONG 9N14W 10N34W 11N37W 10N50W 9N54W TO INLAND OVER SOUTH AMERICA NEAR 8N72W. A MODERATE TO STRONG CLUSTER OF CONVECTION LIES JUST NORTH OF THE AXIS...OFF THE COAST OF AFRICA FROM 8N-12N BETWEEN 15W-17W. JUST TO THE SW OF THIS CLUSTER LIES ANOTHER CLUSTER OF SCATTERED MODERATE CONVECTION FROM 4N-8N BETWEEN 17W-21W. THERE ALSO APPEARS TO BE SOME BROAD CYCLONIC TURNING IN THIS REGION. THIS ALONG WITH ANALYSIS OF THE HOVMOLLER DIAGRAMS ON THE TAFB WEBSITE SUGGEST A DEVELOPING TROPICAL WAVE MAY BE MOVING OFF OF AFRICA. A SMALL CLUSTER OF MODERATE CONVECTION IS NOTED NEAR 7N27W. WIDELY SCATTERED MODERATE CONVECTION LIE WITHIN 200NM OF THE AXIS BETWEEN 34W-50W. A CLUSTER OF MODERATE CONVECTION IS ALSO SEEN MOVING N FROM THE NE VENEZUELAN COAST. ...DISCUSSION... THE GULF OF MEXICO... THE MAIN FEATURE IN THE GULF IS A MID TO UPPER LEVEL LOW MOVING INTO THE WRN PORTION...CENTERED NEAR 24N93W. THERE IS A REFLECTION OF THIS AT THE SURFACE WITH CYCLONIC TURNING NOTED ON NEARBY BUOY OBSERVATIONS...THOUGH AN EARLIER QUIKSCAT PASS SUGGESTED THERE WAS NOT A CLOSED LOW AND THUS THE LOW HAS BEEN REMOVED AND NOW A TROUGH IS PLACED ON THE MAP EXTENDING NE FROM 21N95W TO 28N89W. ISOLATED SHOWERS AND TSTMS ASSOCIATED WITH THIS FEATURE DOT THE WRN GULF FROM 23N-28N BETWEEN 90W-98W. WIDELY SCATTERED MODERATE CONVECTION ARE ALSO NOTED IN THE ERN GULF S OF 28N PUSHING SW AROUND THE SE PORTION OF AN UPPER ANTICYCLONE NEAR MEMPHIS TENNESSEE. LOOK FOR THESE SHOWERS AND TSTMS TO GRADUALLY SPREAD W THROUGH THE GULF OVER THE NEXT 24HRS. THE CARIBBEAN SEA... THE MOST SIGNIFICANT WEATHER IN THE CARIBBEAN IS A CLUSTER OF MODERATE TO STRONG CONVECTION IN THE SRN CARIBBEAN OFF THE COAST OF PANAMA/COLOMBIA. CLOUD TOPS ASSOCIATED WITH THE CLUSTER OF SCATTERED MODERATE CONVECTION BETWEEN JAMAICA AND CENTRAL CUBA HAVE BEEN WARMING OVER THE LAST FEW HOURS...THOUGH NEW/SMALLER CELLS HAVE DEVELOPED NEAR 21N79W AND NEAR 19N75W. THIS ACTIVITY SEEMS TO BE COLOCATED WITH A DISTINCT AREA OF UPPER DIFFLUENCE AND A LINGERING UPPER LOW JUST TO THE S OF WRN CUBA. MID TO UPPER LEVEL W/WSW FLOW IS DOMINATING THE CENTRAL AND ERN CARIBBEAN TONIGHT...FEEDING INTO THE LARGE UPPER LOW NE OF THE LEEWARD ISLANDS. THIS IS BLOWING OFF THE TOPS OF THE CONVECTION ALONG THE ITCZ OVER SOUTH AMERICA...WITH SOME SCATTERED SHOWERS AND TSTMS SPILLING OVER INTO THE SRN CARIBBEAN FROM 11N-15N BETWEEN 61W-75W. AT THE SURFACE...THE SW PORTION OF THE ATLC HIGH IS INTERACTING WITH THE COLOMBIAN LOW...PRODUCING 15-20 KT TRADES OVER MUCH OF THE CARIBBEAN. THE ATLANTIC OCEAN... THE PERSISTENT SURFACE LOW PRESSURE AREA OFF THE SOUTHEAST COAST OF THE UNITED STATES IS NOW CENTERED ABOUT 85NM ENE OF JACKSONVILLE. SATELLITE AND RADAR DATA INDICATE THAT THE ASSOCIATED SHOWER ACTIVITY IS POORLY ORGANIZED...AND UPPER LEVEL WINDS ARE NOT FAVORABLE FOR TROPICAL CYCLONE DEVELOPMENT. UW-CIMMS SHEAR ANALYSIS DEPICTS ABOUT 30 KTS OF NORTHERLY SHEAR CURRENTLY OVER THIS REGION. SHOWERS AND THUNDERSTORMS WITH BRIEF GUSTY WINDS COULD STILL AFFECT COASTAL AREAS OF GEORGIA AND NORTHEASTERN FLORIDA DURING THE NEXT DAY OR SO AS THE SYSTEM MOVES SLOWLY SOUTHWESTWARD. WIDELY SCATTERED MODERATE CONVECTION IS SEEN ENE OF THE BAHAMAS FROM 24N-30N BETWEEN 67W-74W. THIS APPEARS TO BE ASSOCIATED WITH UPPER DIFFLUENCE ALONG WITH PERHAPS SOME WEAK SURFACE TROUGHING. JUST TO THE E OF THIS AREA LIES SCATTERED SHOWERS AND TSTMS FROM 20N-30N BETWEEN 53W-65W. THERE IS A WELL DEFINED UPPER LOW IN THIS VICINITY...WITH THE CENTER NEAR 23N63W. MUCH OF THE CENTRAL AND ERN ATLC FROM 15N-30N BETWEEN THE COAST OF AFRICA AND 55W IS DOMINATED BY A PAIR OF UPPER HIGHS...FAIR WEATHER...AND WEAK SURFACE HIGH PRESSURE. BETWEEN THE UPPER HIGHS...THERE IS A NARROW UPPER TROUGH AXIS EXTENDING N/S ALONG 39W. THERE IS A WEAK REFLECTION OF THIS TO THE SURFACE AS VERIFIED BY AN EARLIER QUIKSCAT PASS AND LOW CLOUD MOTIONS...THOUGH SHOWER AND TSTM ACTIVITY ASSOCIATED WITH THIS FEATURE IS MINIMAL S OF 32N. $$ WILLIS