000 AXNT20 KNHC 021748 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT SAT SEP 02 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 1730 UTC. ...TROPICAL WAVES... A NEW ERN ATLC TROPICAL WAVE IS ADDED TO THE 1200 UTC MAP ALONG 20W/21W S OF 17N MOVING W 15 TO 20 KT. CYCLONIC CURVATURE IS SEEN IN LOW CLOUD MOTIONS ON VISIBLE IMAGERY...BUT THE MAIN JUSTIFICATION FOR ADDING THIS WAVE LIES IN THE VEERING SEEN IN THE LOW LEVEL WINDS IN THE DAKAR SOUNDING OVER THE LAST 24 TO 36HRS. CLOUD TOPS HAVE WARMED A FEW DEGREES OVER THE ASSOCIATED CLUSTER OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION THAT MOVED OFF AFRICA LAST EVENING...THOUGH SCATTERED MODERATE STILL LIES FROM 11N-16N BETWEEN 22W-25W. GFS SEEMS TO HAVE THIS INITIALIZED FAIRLY WELL...THOUGH THE MODELS PLACEMENT IS SLIGHTLY E OF MINE. THERE MAY BE A WEAK SURFACE LOW FORMING ALONG THIS WAVE BUT MY CONFIDENCE IN THIS AT 1200 UTC WAS NOT HIGH. TROPICAL WAVE IS ALONG 39W S OF 18N WITH A 1009 MB LOW ALONG THE WAVE NEAR 11N MOVING W NEAR 10 KT. BROAD ELONGATED LOW/MID LEVEL CIRCULATION IS OBSERVED ON SATELLITE IMAGERY. SCATTERED MODERATE CONVECTION IS OBSERVED FROM 12N-15N BETWEEN 36W-44W. ISOLATED SHOWERS/TSTMS ARE NOTED S OF 11N WITHIN 150 NM OF EITHER SIDE OF THE AXIS. THE CLUSTER OF MODERATE CONVECTION E OF THE WAVE MAY BE MORE ASSOCIATED WITH THE ITCZ. THIS SYSTEM HAS SOME POTENTIAL FOR DEVELOPMENT OVER THE NEXT FEW DAYS. TROPICAL WAVE MOVING THROUGH THE LESSER ANTILLES IS ALONG 60W S OF 19N WITH A 1010 MB LOW ALONG THE WAVE NEAR 15N MOVING W 10 TO 15 KT. THE SHOWER ACTIVITY HAS BECOME A LITTLE BETTER ORGANIZED DURING THE PAST FEW HOURS AND SURFACE PRESSURES HAVE BEEN FALLING. HOWEVER...UPPER-LEVEL WINDS ARE EXPECTED TO BECOME ONLY SLIGHTLY MORE CONDUCIVE FOR DEVELOPMENT...IF ANY AT ALL. SCATTERED MODERATE/ISOLATED STRONG CONVECTION EXISTS FROM 12N-19N BETWEEN 58W-65W. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 14N17W 12N22W 12N37W 11N43W 12N57W AND REEMERGES IN THE SW CARIBBEAN NEAR THE COLOMBIAN COAST NEAR 10N76W AND EXTENDS W THROUGH PANAMA AND EXITS INTO THE EPAC NEAR PAVONES COSTA RICA. ASIDE FROM THE ACTIVITY ASSOCIATED WITH THE TROPICAL WAVES/LOWS...A COUPLE CLUSTERS OF SCATTERED MODERATE WITH ISOLATED STRONG CONVECTION ARE BEGINNING TO MOVE OFF THE COAST OF AFRICA FROM 13N-20N BETWEEN AFRICA AND 19W. SCATTERED MODERATE CONVECTION IS FROM 8N-15N BETWEEN 32W-37W. CLUSTERS OF MODERATE CONVECTION ARE ALSO AFFECTING THE SW CARIBBEAN SEA OFF CENTRAL AMERICA. ...DISCUSSION... GULF OF MEXICO... THE MOST ACTIVE WEATHER IN THE GULF THIS AFTERNOON LIES IN THE FLORIDA STRAITS AND FAR SE GULF. DOPPLER RADAR SHOWS NUMEROUS SHOWERS AND TSTMS IN THIS REGION...LIKELY ASSOCIATED WITH UPPER DIFFLUENT AIR BETWEEN A WEAK MID TO UPPER LEVEL SHORT WAVE RIDGE EXTENDING THROUGH THE ERN GULF...AND THE UPPER LOW SEEN SPINNING OVER THE SE BAHAMAS. A NARROW UPPER TROUGH IS EXTENDING NE THROUGH THE BAY OF CAMPECHE...THROUGH THE CENTRAL GULF AND TOWARDS THE WRN FLORIDA PANHANDLE. THERE IS A WEAK REFLECTION OF THIS AS A TROUGH AT THE SURFACE...EXTENDING FROM 21N96W TO 30N84W. ISOLATED SHOWERS AND TSTMS ARE WITHIN 100NM OF THIS AXIS. THE FAR NW GULF IS QUIET WITH VERY DRY MID TO UPPER LEVEL AIR DOMINATING ON THE E SIDE OF AN UPPER HIGH OVER NRN MEXICO. OVERALL A FAIRLY WEAK GRADIENT WITH LIGHT WINDS/LOW SEAS EXPECTED TO DOMINATE THE GULF SFC PATTERN OVER THE NEXT COUPLE DAYS. CARIBBEAN SEA... FAIR WEATHER DOMINATES MUCH OF THE CARIBBEAN OUTSIDE OF THE TROPICAL WAVE AND SURFACE LOW OVER THE WINDWARD ISLANDS AND THE ITCZ ACTIVITY OFF CENTRAL AMERICA. THERE ARE A FEW ISOLATED SHOWERS AND TSTMS MOVING S INTO THE NW CARIBBEAN WATERS S OF CUBA...AROUND THE W SIDE OF THE UPPER LOW OVER THE SE BAHAMAS. A MID TO UPPER LEVEL HIGH IS SEEN JUST NORTH OF THE WAVE/LOW OVER THE WINDWARD ISLANDS. MID TO UPPER LEVEL SW FLOW ON THE W OF THIS HIGH/SE OF THE LOW OVER THE SE BAHAMAS IS STREAMING HIGH CLOUDS TO THE NE BETWEEN COLOMBIA/VENEZUELA AND PUERTO RICO/VIRGIN ISLANDS. 10-20 KT TRADES DOMINATE MUCH OF THE CARIBBEAN. THIS WILL PERSIST OVER THE NEXT 24HRS WHILE SHOWERS/TSTMS CONTINUE MOVING THROUGH THE ERN CARIBBEAN. ATLANTIC OCEAN... AN UPPER HIGH IS SEEN ON WV IMAGERY JUST ESE OF CAPE HATTERAS. UPPER DIFFLUENT AIR BETWEEN THIS FEATURE AND THE UPPER LOW OVER THE SE BAHAMAS IS HELPING TO SUPPORT THE SCATTERED SHOWERS AND TSTMS IN THE FAR WRN ATLC AND ACROSS THE BAHAMAS/S FLORIDA FROM 22N-29N BETWEEN 75W-81W. ISOLATED SHOWERS/TSTMS ARE ROTATING CYCLONICALLY AROUND THE UPPER LOW OVER THE SE BAHAMAS FROM 22N-69W BETWEEN 65W-75W. A BENIGN UPPER LOW IS SEEN SPINNING NEAR 26N45W. MID TO UPPER LEVEL HIGHS ARE SEEN NEAR 18N31W AND ANOTHER OVER THE COAST OF AFRICA NEAR 19N15W. AT THE SURFACE...A 1021MB HIGH S OF THE AZORES IS CENTERED NEAR 33N30W. THE ANTICYCLONIC FLOW AROUND THIS HIGH IS DOMINATING MUCH OF OUR ATLANTIC AREA N OF 15N. EXTENSIVE DRY AIR ALONG WITH A DENSE SAHARAN DUST EXTENDS OUT TO NEAR 50W MAINLY N OF 15N. $$ WILLIS