000 AXNT20 KNHC 262354 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT TUE SEP 26 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2345 UTC. ...SPECIAL FEATURE... A 1011 MB SURFACE LOW PRESSURE CENTER IS NEAR 23N50W...OR ABOUT 740 NM EAST-NORTHEAST OF THE NORTHERN LEEWARD ISLANDS. THE CLOUDINESS AND SHOWERS ASSOCIATED WITH THIS LOW HAVE CHANGED LITTLE IN ORGANIZATION THIS AFTERNOON. THIS SYSTEM STILL HAS SOME POTENTIAL FOR TROPICAL CYCLONE FORMATION DURING THE NEXT DAY OR TWO AS IT MOVES NORTHWESTWARD. NUMEROUS MODERATE/ISOLATED STRONG CONVECTION REMAINS MOSTLY E AND NE OF THE CENTER FROM 23N-26N BETWEEN 46W-50W. ...TROPICAL WAVES... A NEW TROPICAL WAVE HAS EMERGED OFF THE COAST OF AFRICA ALONG 18W S OF 15N MOVING W NEAR 10 KT. THIS WAVE IS ACCOMPANIED BY A 1011MB SURFACE LOW NEAR 11N...AS VERIFIED BY THE AVAILABLE SURFACE/SHIP OBSERVATIONS NEARBY AND LOW CLOUD MOTIONS. CONVECTION ASSOCIATED WITH THE WAVE HAS BEEN ON THE DECREASE OVER THE LAST FEW HOURS...WITH SCATTERED SHOWERS/TSTMS NOW NOTED WITHIN 100NM OF THE WAVE AXIS. TROPICAL WAVE IS ALONG 36W SOUTH OF 16N MOVING WEST NEAR 15 KT. THIS POSITION IS BASED ON CONTINUITY AND HOVMOLLER DIAGRAMS AS CYCLONIC TURNING IS VAGUE...WITH AN ELONGATED E/W TROUGH AROUND 10N ASSOCIATED WITH THE ITCZ IN THE VICINITY. THE MOST SIGNIFICANT CONVECTION REMAINS W OF THE WAVE POSITION FROM 10N-13N BETWEEN 30W-36W...BUT AGAIN THIS MAY BE MORE ASSOCIATED WITH THE ITCZ. THE 26/2000 UTC QUIKSCAT PASS DOES SHOW SOME SUBTLE CYCLONIC TURNING NEAR THE WAVE AXIS BUT SUGGESTS A VERY LOW AMPLITUDE FEATURE. TROPICAL WAVE IS ALONG 52W/53W SOUTH OF 16N DRIFTING WEST. THIS WAVE HAS BEEN MOVING IN TANDEM WITH THE SURFACE LOW MENTIONED IN THE SPECIAL FEATURE SECTION. ISOLATED SHOWERS ARE RELATED TO THE WAVE. THERE IS A CLUSTER OF MODERATE CONVECTION NW OF THE WAVE FROM 16N-19N BETWEEN 53W-56W...IN A REGION OF LOW LEVEL CONFLUENCE. A TROPICAL WAVE EXTENDS FROM THE SE BAHAMAS ACROSS WRN HAITI TO NRN COLOMBIA...ALONG 73W/74W MOVING W 10 TO 15 KT. THE NORTHERN PORTION OF THE WAVE MAY BE ENHANCING THE SCATTERED SHOWERS OVER THE SOUTHERN BAHAMAS...HISPANIOLA...CUBA AND THE ADJACENT WATERS AS IT INTERACTS WITH AN UPPER TROUGH OVER THIS AREA. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 10N20W 10N32W 8N39W 9N50W 10N55W 9N61W. OUTSIDE FROM THE CONVECTION ASSOCIATED WITH THE TROPICAL WAVES...SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS BEGINNING TO EMERGE OFF THE COAST OF SIERRA LEONE FROM 6N-11N EAST OF 14W. SCATTERED MODERATE CONVECTION IS FROM 8N-12N BETWEEN 23W-27W...FROM 10N-13N BETWEEN 30W-36W...AND FROM 7N-11N BETWEEN 40W-49W. ...DISCUSSION... THE GULF OF MEXICO... A COLD FRONT CONTINUES TO EXTEND FROM CENTRAL FLORIDA TO THE CENTRAL GULF NEAR 25N90W...AND THEN BECOMES STATIONARY FROM THIS POINT THROUGH THE BAY OF CAMPECHE. SHOWER AND TSTM ACTIVITY ASSOCIATED WITH THIS FRONT ARE OVERALL MINIMAL/ISOLATED AT BEST OVER THE GULF THIS EVENING. A MID TO UPPER LEVEL HIGH IS JUST S OF MAZATLAN MEXICO THIS EVENING THAT HAS RIDGING AFFECTING MUCH OF THE GULF WITH THE AXIS ALONG 25N/26N. DEEP LAYER CYCLONIC FLOW SEEN IN THE FAR NE GULF AROUND THE TROUGHING AFFECTING THE ERN UNITED STATES. AFTERNOON CONVECTION OVER THE YUCATAN PENINSULA AND WRN CUBA IS STREAMING TO THE WEST INTO THE ADJACENT GULF WATERS AROUND THE UPPER HIGH AFFECTING THE AREA. ELSEWHERE AT THE SURFACE BESIDES THE FRONT...A 1021MB HIGH IS BUILDING OVER THE NW GULF FROM NW LOUISIANA. LOOK FOR THE FRONT AND HIGH FROM TX/LA TO CONTINUE MOVING SLOWLY SE OVER THE NEXT 24 HRS. THE CARIBBEAN SEA... THE MOST ACTIVE WEATHER IN THE CARIBBEAN THIS EVENING IS IN THE WRN PORTION AROUND 80W. NUMEROUS MODERATE/ISOLATED STRONG CONVECTION IS FROM 11N-19N BETWEEN 78W-83W...WITH THE STRONGEST CONVECTION GENERALLY BETWEEN NICARAGUA AND JAMAICA. THIS SEEMS MOSTLY ASSOCIATED WITH UPPER DIFFLUENCE BETWEEN A WELL DEFINED UPPER HIGH OVER THE CENTRAL CARIBBEAN NEAR 14N74W AND UPPER TROUGHING OVER THE FAR NW CARIBBEAN. THESE SHOWERS AND THUNDERSTORMS ARE DISORGANIZED...AND SURFACE PRESSURES IN THE REGION NOT FALLING. FURTHER DEVELOPMENT IS NOT EXPECTED. TRADES CONTINUE IN THE 15 TO 20 KT RANGE ON THE SW PORTION OF THE ATLC HIGH AND ITS INTERACTION WITH LOWER PRESSURE NEAR COLOMBIA. SIMILAR TRADES EXPECTED THE NEXT COUPLE OF DAYS. THE ATLANTIC OCEAN... A COLD FRONT EXTENDS NE FROM CENTRAL FLORIDA INTO THE ATLANTIC WITH ISOLATED SHOWERS/TSTMS WITHIN 150NM OF THE FRONT. THE MOST SIGNIFICANT AREA OF SHOWERS WITH EMBEDDED TSTMS IS MOVING OFF CENTRAL FLORIDA FROM 27N-29N BETWEEN 78W-81W. AN UPPER RIDGE COVERS THE SW NORTH ATLC OUT TO 70W FROM ITS ORIGIN S OF MAZATLAN MEXICO. AN UPPER LOW IS NEAR 27N67W THAT HAS TROUGHING EXTENDING THROUGH THE SE BAHAMAS. UPPER DIFFLUENCE BETWEEN THIS FEATURES AND THE LARGE SCALE TROUGHING OVER ERN UNITED STATES IS HELPING TO SUPPORT THE CLUSTER OF SCATTERED MODERATE CONVECTION FROM 27N-32N BETWEEN 69W-73W. LOW CLOUD MOTIONS ALSO REVEALED THERE IS A 1019MB SURFACE HIGH IN THIS REGION NEAR 26N69W. THE FLOW AROUND THIS IS COLLIDING WITH THE FLOW AROUND A CENTRAL ATLC 1023MB HIGH NEAR 31N44W TO PRODUCE A SURFACE TROUGH ALONG 25N63W 33N63W. ISOLATED SHOWERS/TSTMS ARE SEEN WITHIN 40NM OF THIS TROUGH THAT IS A LEFTOVER PIECE OF AN OLD FRONTAL BOUNDARY. ANOTHER UPPER LOW IS NEAR 25N57W THAT IS PRODUCING SWLY SHEAR OVER THE SPECIAL FEATURE AS IT INTERACTS WITH BROAD UPPER RIDGING EXTENDING W FROM AFRICA TO NEAR 50W. THERE ARE A FEW EMBEDDED UPPER HIGH CENTERS IN THIS REGION SEEN ON WV IMAGERY. N OF THIS REGION IN THE ERN ATLC LIES THE TAIL END OF A SURFACE COLD FRONT ALONG 32N22W 27N28W. MID TO UPPER CYCLONIC FLOW IS DOMINATING THE ERN ATLC FROM 20N TO 32N BETWEEN THE COAST OF AFRICA AND 35W ASSOCIATED WITH A WELL DEFINED UPPER LOW NEAR 31N23W. $$ WILLIS