000 AXNT20 KNHC 280001 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT WED SEP 27 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... SATELLITE IMAGES INDICATE THAT THE NINTH TROPICAL DEPRESSION OF THE 2006 HURRICANE SEASON HAS FORMED OVER THE CENTRAL ATLANTIC. AT 500 PM EDT...2100 UTC...THE CENTER OF TROPICAL DEPRESSION NINE WAS LOCATED NEAR LATITUDE 26.5 NORTH...LONGITUDE 53.1 WEST OR ABOUT 700 NM EAST-SOUTHEAST OF BERMUDA. THE DEPRESSION IS MOVING TOWARD THE NORTHWEST NEAR 12 KT. THIS GENERAL MOTION IS EXPECTED TO CONTINUE DURING THE NEXT 24 HOURS. THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 1012 MB. MAXIMUM SUSTAINED WINDS ARE NEAR 30 KT WITH GUSTS TO 40 KT. SOME SLOW STRENGTHENING IS FORECAST...AND THE DEPRESSION COULD BECOME A TROPICAL STORM DURING THE NEXT 24 HOURS. SEE THE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT4/WTNT24 KNHC AND THE PUBLIC ADVISORY UNDER MIATCPAT4/WTNT34 KNHC FOR MORE DETAILS. SCATTERED TO NUMEROUS MODERATE CONVECTION IS FROM 22N-30N BETWEEN 48W-54W. ...TROPICAL WAVES... AN EASTERN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 20W/21W SOUTH OF 18N MOVING WEST NEAR 10 KT. A 1010 MB LOW PRESSURE CENTER IS ALONG THE WAVE AXIS NEAR 12.5N. THE AVAILABLE SURFACE AND SHIP OBSERVATIONS IN THE VICINITY SHOW CLEAR CYCLONIC CURVATURE ABOUT THE WAVE AXIS. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 9N-19N BETWEEN 19W-23W. A LOW AMPLITUDE ATLANTIC OCEAN TROPICAL WAVE IS ALONG 42W/43W SOUTH OF 15N MOVING WEST NEAR 15 KT. THE WAVE IS SUBTLE WITH THE PLACEMENT BASED ON CONTINUITY AND HOVMOLLER DIAGRAMS. CONVECTION IS MINIMAL AND CONFINED MOSTLY NEAR THE ITCZ WITH SCATTERED MODERATE FROM 9N-12N BETWEEN 40W-47W. A TROPICAL WAVE IS APPROACHING THE LESSER ANTILLES ALONG 58W SOUTH OF 20N MOVING WEST 10 TO 15 KT. SATELLITE IMAGERY AND THE AVAILABLE SURFACE OBSERVATIONS SUGGEST A WEAK SURFACE LOW MAY BE FORMING ALONG THE LOW NEAR 17N. HOWEVER...THE CONVECTION IN THIS REGION A COUPLE HUNDRED MILES E OF THE LEEWARD ISLANDS HAS BEEN DECREASING IN BOTH COVERAGE AND INTENSITY OVER THE LAST FEW HOURS. ALTHOUGH SIGNIFICANT DEVELOPMENT OF THIS SYSTEM IS NOT ANTICIPATED...IT COULD BRING SHOWERS AND GUSTY WINDS TO PORTIONS OF THE LESSER ANTILLES DURING THE NEXT DAY OR SO. A TROPICAL WAVE IS OVER THE WESTERN CARIBBEAN SEA ALONG 78W MOVING WEST NEAR 15 KT. CONVECTION REMAINS LIMITED TO MOSTLY THE NORTHERN PORTION OF THE WAVE WITH SCATTERED MODERATE FROM 16N-20N BETWEEN 76W-83W. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 13N16W 11N30W 9N40W 9N50W TO TRINIDAD NEAR 10N61W. OTHER THAN THE CONVECTION MENTIONED IN THE TROPICAL WAVE SECTION...ISOLATED MODERATE CONVECTION IS FROM 8N-11N BETWEEN 46W-51W...AND ALSO NEAR NE TRINIDAD AND TOBAGO. ...DISCUSSION... THE GULF OF MEXICO... A QUASI-STATIONARY FRONTAL BOUNDARY EXTENDS FROM S FLORIDA TO THE BAY OF CAMPECHE ALONG 27N82W 24N90W 18N94W. THE FRONT SEEMS TO BE PROGRESSING SE MORE THAN IT WAS AT 1800 UTC...SO HAVE OPTED TO MAKE IT A PROGRESSIVE COLD FRONT ON THE 2100 UTC MAP OVER FL AND ERN GULF. CONVECTION OVER THE GULF ASSOCIATED WITH THE FRONT REMAINS ISOLATED AT BEST WITHIN 100NM OF THE FRONT. THE STRONGEST SHOWERS/TSTMS HAVE BEEN MOVING THROUGH SE FLORIDA AND NOW INTO THE ADJACENT ATLC WATERS. THERE IS A SWATH OF MID TO UPPER LEVEL MOISTURE WITH A FEW SHOWERS IN THE W GULF FROM 20N-27N BETWEEN 90W-98W...BUT THIS SEEMS MORE ASSOCIATED WITH UPPER DIFFLUENCE BETWEEN AN UPPER RIDGE EXTENDING E FROM JUST S OF CABO SAN LUCAS AND TROUGHING OVER THE CENTRAL/ERN US. THERE IS A 1020MB SURFACE HIGH JUST S OF THE WRN LOUISIANA COAST. THIS HIGH IS EXPECTED TO DRIFT SLOWLY W WHILE WEAKENING OVER THE NEXT 24HRS WHILE THE NEXT COLD FRONT APPROACHES FROM THE NW. THE FRONT EXTENDING THROUGH S FLORIDA WILL CONTINUE DRIFTING SLOWLY SE WHILE WEAKENING. THE CARIBBEAN SEA... WELL DEFINED MID TO UPPER LEVEL HIGH IS DOMINATING THE WRN HALF OF THE CARIBBEAN THIS EVENING WITH AN ESTIMATED CENTER FROM WV IMAGERY AND GOES WINDS NEAR 13N79W. THERE MAY ALSO BE A WEAKER EMBEDDED UPPER HIGH CENTER NEAR 16N84W OR JUST OFF THE COAST OF HONDURAS. UPPER DIFFLUENCE BETWEEN THIS SMALLER HIGH AND THE LARGER/BROAD HIGH SEEMS TO BE ASSISTING IN THE CONVECTION MENTIONED WITH THE TROPICAL WAVE ALONG 78W...BETWEEN HONDURAS AND CUBA. THE ONLY OTHER MID TO UPPER LEVEL MOISTURE WITH ISOLATED SHOWERS SEEN IS BETWEEN HISPANIOLA AND VENEZUELA. THIS IS A MORE OBVIOUS REGION OF UPPER DIFFLUENCE BETWEEN THE UPPER HIGH NEAR 13N79W AND UPPER TROUGHING N OF HISPANIOLA/PUERTO RICO. 10 TO 20 KT TRADES PERSIST THIS EVENING WITH SW PORTION OF THE ATLC HIGH INTERACTING WITH LOWER PRESSURE NEAR THE COLOMBIAN COAST. THE ATLANTIC OCEAN... A QUASI-STATIONARY FRONT IS OVER THE W ATLANTIC ALONG 31N74W 27N80W. THE FRONT IS NOW DRIFTING SLOWLY SE AS A COLD FRONT. ISOLATED MODERATE CONVECTION MOSTLY AHEAD OF THE FRONT IS FROM 23N-30N BETWEEN 68W-80W...ALSO BEING SUPPORTED BY UPPER DIFFLUENCE BETWEEN AN UPPER RIDGE EXTENDING ENE THROUGH THE BAHAMAS AND THE UPPER SW FLOW OFF THE SE US COAST. THERE IS AN UPPER LOW JUST W OF TROPICAL DEPRESSION 9 NEAR 28N59W AND A UPPER HIGH TO THE EAST OF THE DEPRESSION NEAR 26N48W. A WELL DEFINED UPPER LOW IS NEAR 25N28W IN THE ERN ATLC BUT IS NOT GENERATING MUCH SHOWER ACTIVITY IN THE IMMEDIATE VICINITY. THERE IS A CLUSTER OF MODERATE CONVECTION JUST WSW OF THE CANARY ISLANDS THAT IS ASSOCIATED WITH UPPER DIFFLUENCE BETWEEN THE UPPER LOW TO THE W AND AN UPPER HIGH OVER WRN AFRICA. ELSEWHERE AT THE SURFACE...A 1026MB HIGH IS AFFECTING MUCH OF THE REGION FROM ITS CENTER IN THE CENTRAL ATLANTIC NEAR 34N45W. $$ WILLIS