000 AXNT20 KNHC 091809 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT WED AUG 09 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 1700 UTC. ...SPECIAL FEATURE... A STRONG TROPICAL WAVE LOCATED ABOUT 195 MILES EAST OF THE WINDWARD ISLANDS IS MOVING WESTWARD AT 15 TO 20 KT. SHOWER AND THUNDERSTORM ACTIVITY HAS BECOME MORE CONCENTRATED THIS MORNING...AND AN AIR FORCE RESERVE RECONNAISSANCE AIRCRAFT WILL REACH THE SYSTEM THIS AFTERNOON TO DETERMINE IF A TROPICAL DEPRESSION OR STORM HAS FORMED. REGARDLESS OF TROPICAL CYCLONE DEVELOPMENT...THE SYSTEM WILL SPREAD SHOWERS AND THUNDERSTORMS WITH GUSTY WINDS TO TROPICAL STORM FORCE IN SQUALLS OVER PORTIONS OF THE LESSER ANTILLES LATER TODAY AND TONIGHT. NUMEROUS MODERATE/ISOLATED STRONG CONVECTION IS APPROACHING THE WINDWARD ISLANDS FROM 11N TO 16N BETWEEN 56W AND 61W. A SURFACE LOW HAS BEEN REPLACED ON THE WAVE AXIS NEAR 13N55W DUE TO THIS BURST ALONG WITH LOW CLOUD MOTIONS SPIRALING CYCLONICALLY INTO THE SYSTEM. ...TROPICAL WAVES... AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 37W SOUTH OF 21N MOVING WEST 15 KT. LOW CLOUD MOTIONS EXHIBIT CLEAR CYCLONIC CURVATURE ABOUT THE AXIS WITH A NOTED INVERTED V PATTERN...ESPECIALLY N OF 11N BETWEEN 33W AND 42W. DEEP CONVECTION IN THE VICINITY OF THIS WAVE HAS REMAINED AT A MINIMUM TODAY. ONLY ISOLATED SHOWERS AND TSTMS EVIDENT WITHIN 250NM OF EITHER SIDE OF THE AXIS...AND THOSE ARE MAINLY IN THE VICINITY OF THE ITCZ. A WESTERN CARIBBEAN SEA TROPICAL WAVE IS ALONG 84W SOUTH OF 24N MOVING WEST 15 KT. SCATTERED MODERATE CONVECTION IS AFFECTING CENTRAL AMERICA AND THE SW CARIBBEAN FROM 8N TO 15N BETWEEN 78W AND 87W. THE NORTHERN PORTION OF THIS WAVE IS INTERACTING WITH AN UPPER LOW PUSHING OFF THE W COAST OF FLORIDA...BUT CONVECTION IN THIS VICINITY OF THE WAVE N OF 18N HAS DIMINISHED QUITE A BIT SINCE YESTERDAY. ONLY ISOLATED SHOWERS AND THUNDERSTORMS ARE NOTED IN THE NW CARIBBEAN AND SOUTHEAST/SOUTH CENTRAL GULF OF MEXICO. ...THE ITCZ... THE ITCZ AXIS IS CENTERED ALONG 13N16W 10N36W 10N39W 12N52W 11N57W TO INLAND OVER NE SOUTH AMERICA NEAR 8N66W. ISOLATED MODERATE CONVECTION LIES JUST OFF THE W COAST OF AFRICA FROM 7N TO 13N BETWEEN 13W AND 19W. ASIDE FROM THE SPECIAL FEATURE...VERY LITTLE SIGNIFICANT CONVECTION IS NOTED ELSEWHERE ALONG THE AXIS W OF 20W. ...DISCUSSION... THE GULF OF MEXICO... A MID TO UPPER LEVEL LOW IS SEEN SPINNING JUST OFF THE WEST COAST OF FLORIDA IN THE ERN GULF THIS AFTERNOON. MID/UPPER LEVEL ENE/E FLOW DOMINATES THE REST OF THE GULF AREA OUTSIDE OF THE UPPER LOW...ON THE SOUTH SIDE OF UPPER ANTICYCLONES OVER N TEXAS AND NE MISSISSIPPI. SCATTERED SHOWERS AND THUNDERSTORMS WITH EMBEDDED ISOLATED MODERATE CONVECTION LIES IN THE SW GULF FROM 18N TO 25N BETWEEN 93W AND COASTAL MEXICO...AN AREA WHICH IS UNDER THE INFLUENCE OF WEAK UPPER DIFFLUENCE. THERE ARE A FEW ISOLATED SHOWERS IN THE CENTRAL GULF NEAR THE BASE OF THE UPPER LOW OFF THE W COAST OF FLORIDA...BUT CLOUD TOPS REMAIN WARM AND HEAVILY SHEARED. AT THE SURFACE...5 TO 15 KT E/SE FLOW DOMINATES ON THE SW SIDE OF HIGH PRESSURE OVER N FLORIDA AND THE WRN ATLC. THIS LOOKS TO CONTINUE OVER THE NEXT COUPLE OF DAYS...WHILE THE UPPER LOW MOVES INTO THE WRN GULF. THE CARIBBEAN SEA... THE SOUTHERN PORTION OF THE UPPER LOW OFF OF W FLORIDA IS EXTENDING INTO THE NW CARIBBEAN AND YUCATAN CHANNEL. A SMALL CLUSTER OF MODERATE CONVECTION IS LOCATED NEAR CANCUN MEXICO...LIKELY DUE TO THE INTERACTION OF THE UPPER LOW WITH THE TROPICAL WAVE ALONG 84W. MID TO UPPER LEVEL ANTICYCLONIC MOTION IS NOTED IN THE SW GULF OFF THE CENTRAL AMERICAN COAST. BROAD UPPER NE/E FLOW IS DOMINATING MUCH OF THE CENTRAL AND ERN CARIBBEAN. A LINE OF SCATTERED MODERATE CONVECTION IS EXTENDING THROUGH THE MIDDLE CARIBBEAN WATERS FROM 13N TO 17N BETWEEN THE WINDWARD ISLANDS AND 77W. THIS IS ASSOCIATED WITH LOW LEVEL CONFLUENCE AND WEAK UPPER DIFFLUENCE. THE 09/12Z UW CIMMS SAHARAN LAYER ANALYSIS SHOWS THIS CONVECTION IS ALSO ALONG A DEMARCATION LINE ALONG THE EDGE OF THE LATEST SURGE OF AFRICAN DUST. 15 TO 25KT TRADE FLOW CONTINUES TO DOMINATE MUCH OF THE CARIBBEAN THIS AFTERNOON...WITH THE STRONGEST WINDS GENERALLY BETWEEN THE COLOMBIAN COAST AND HISPANIOLA ...AS ATLC HIGH PRESSURE TO THE NORTH INTERACTS WITH LOWER PRESSURE NEAR COLOMBIA. SIMILAR CONDITIONS EXPECTED OVER THE NEXT COUPLE OF DAYS...THOUGH SHOWERS AND TSTMS ASSOCIATED WITH THE SPECIAL FEATURE NEARING THE WINDWARD ISLANDS WILL SPREAD THROUGH THE ERN CARIBBEAN. THE ATLANTIC OCEAN... UPPER LEVEL N/NE FLOW DOMINATES MUCH OF THE SW ATLC BETWEEN THE FLORIDA COAST AND 62W...BETWEEN THE UPPER HIGH OVER THE SE US AND A WEAK UPPER LOW NEAR 21N60W...WHICH IS BEING CONSUMED BY DRY AIR. A BROAD LAYER OF UPPER ANTICYCLONIC MOTION IS SEEN ON WV IMAGERY AGAIN THIS AFTERNOON FROM 5N TO 30N BETWEEN THE AFRICAN COAST AND 50W...WITH THE HIGH CENTER ESTIMATED TO BE NEAR 19N30W. UPPER CYCLONIC MOTION IS EVIDENT IN THE ATLC WATERS JUST SOUTH OF THE SPECIAL FEATURE...AS A MID TO UPPER LOW IS NOTED OVER NE SOUTH AMERICA. SURFACE HIGH PRESSURE CONTINUES TO DOMINATE MUCH OF THE ATLC WATERS FROM 15N TO 30N BETWEEN 20W AND 80W...WITH A 1020MB HIGH CENTER ANALYZED NEAR 29N73W AND A 1022MB CENTER NEAR 27N53W. $$ WILLIS