000 AXNT20 KNHC 112345 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT THU AUG 11 2011 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS OF SOUTH AMERICA...AND 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 2315 UTC. ...SPECIAL FEATURES... A 1010 MB LOW IS CENTERED ABOUT 740 NM W OF THE CAPE VERDE ISLANDS NEAR 13N35W WITH A TROPICAL WAVE EXTENDING NW FROM THE LOW TO 19N41W. SCATTERED MODERATE/STRONG CONVECTION IS FROM 15N-18N BETWEEN 38W-40W. THE ASSOCIATED SHOWER/THUNDERSTORM ACTIVITY HAS BECOME A LITTLE LESS ORGANIZED DURING THE LAST 24 HOURS. HOWEVER...ENVIRONMENTAL CONDITIONS APPEAR FAVORABLE FOR GRADUAL DEVELOPMENT OVER THE NEXT SEVERAL DAYS. THIS SYSTEM HAS A MEDIUM CHANCE OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS AS IT MOVES TOWARD THE W-NW AT 13 KT. A WELL-DEFINED 1011 MB LOW IS CENTERED ABOUT 195 NM S OF THE CAPE VERDE ISLANDS NEAR 11N24W WITH A TROPICAL WAVE EXTENDING N ACROSS THE CAPE VERDE ISLANDS TO 19N23W. SCATTERED MODERATE/ STRONG CONVECTION IS FROM 10N-13N BETWEEN 22W-25W. ENVIRONMENTAL CONDITIONS ARE EXPECTED TO GRADUALLY BECOME MORE CONDUCIVE FOR DEVELOPMENT OVER THE NEXT SEVERAL DAYS AS IT MOVES W AT 13-17 KT. THIS SYSTEM HAS A MEDIUM CHANCE OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS. ...TROPICAL WAVES... TROPICAL WAVE IN THE CENTRAL CARIBBEAN IS ANALYZED FROM 20N75W TO 12N77W MOVING W 10-15 KT. WAVE IS EMBEDDED WITHIN A BROAD AREA OF DEEP LAYERED MOISTURE AS DEPICTED ON THE TOTAL PRECIPITABLE WATER IMAGERY WITH NO ASSOCIATED SHOWERS/DEEP CONVECTION. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS INTO THE E TROPICAL ATLC OFF W AFRICA NEAR 20N16W EXTENDING THROUGH BOTH SURFACE LOWS IN THE SPECIAL FEATURES...11N24W AND 13N35W THEN CONTINUING S TO 5N46W. SCATTERED MODERATE/STRONG CONVECTION IS MOVING OFF W AFRICA WITHIN 75 NM ALONG THE COAST BETWEEN 12N-15N. CLUSTERS OF SCATTERED MODERATE/STRONG CONVECTION ARE FROM 8N-13N BETWEEN 26W-30W. ...DISCUSSION... GULF OF MEXICO... BROAD UPPER RIDGE DOMINATES THE GULF ANCHORED NEAR 28N92W. AN UPPER TROUGH IS OVER SE CONUS INTO THE W ATLC N OF 30N SUPPORTING A SURFACE TROUGH THAT EXTENDS FROM THE W ATLC ACROSS S FLORIDA BETWEEN MIAMI TO THE MIDDLE KEYS TO 24N83W. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE S OF 26N TO OVER CUBA E OF 84W THROUGH THE STRAITS OF FLORIDA. ISOLATED SHOWERS/ THUNDERSTORMS DOT THE REMAINDER OF THE E GULF E OF 91W. A WEAK SURFACE RIDGE CONTINUES TO DOMINATE THE GULF EXTENDING FROM THE W ATLC ACROSS FLORIDA TO THE W GULF WITH A 1015 MB HIGH NEAR 25N88W LEAVING THE REMAINDER OF THE GULF UNDER CLEAR SKIES THIS EVENING. WEAK SURFACE RIDGE WILL CHANGE LITTLE THROUGH TUE. A WEAK COLD FRONT WILL MOVE INTO THE FAR NE GULF LATE SUN MOVING SLOWLY S THROUGH TUE. CARIBBEAN SEA... A SMALL UPPER LOW IS IN THE W CARIBBEAN NEAR 18N83W WHILE A BROAD UPPER RIDGE ANCHORED IN THE CENTRAL ATLC EXTENDS S OVER THE E INTO CENTRAL CARIBBEAN. THE MONSOON TROUGH EXTENDS FROM COLOMBIA INTO THE E PACIFIC REGION S OF PANAMA GENERATING SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS S OF 11N TO INLAND OVER COLOMBIA TO COSTA RICA. AFTERNOON THUNDERSTORMS HAVE AGAIN DEVELOPED OVER JAMAICA...CUBA...AND HAITI MOVING INTO THE ADJACENT COASTAL WATERS. FRESH TO MODERATE EASTERLY TRADE WINDS ARE DEVELOPING ISOLATED SHOWERS OVER THE REMAINDER OF THE W CARIBBEAN W OF THE TROPICAL WAVE LEAVING E CARIBBEAN UNDER MOSTLY CLEAR SKIES THIS EVENING. TRADE WINDS WILL WEAKEN SUN AND MON AS W ATLC SURFACE RIDGE WEAKENS AND SHIFTS N. THE TROPICAL WAVE WILL REACH THE W CARIBBEAN TONIGHT THEN DISSIPATE OVER CENTRAL AMERICA BY LATE SAT NIGHT. ATLANTIC OCEAN... AN UPPER TROUGH IS OVER THE SE CONUS INTO THE W ATLC N OF 30N SUPPORTING A SURFACE TROUGH THAT EXTENDS THROUGH 32N74W ALONG 28N78W ACROSS S FLORIDA NEAR MIAMI INTO THE STRAITS OF FLORIDA AND THE SE GULF OF MEXICO. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE WITHIN 150 NM E OF THE SURFACE TROUGH INTO THE STRAITS OF FLORIDA AND TO OVER CUBA. A WEAK SURFACE RIDGE COVERS THE REMAINDER OF THE W ATLC ANCHORED BY A 1018 MB HIGH NEAR 26N64W AND EXTENDS W ACROSS FLORIDA INTO THE GULF OF MEXICO LEAVING THE REMAINDER OF THE W ATLC W OF 60W UNDER MOSTLY CLEAR SKIES THIS EVENING. AN UPPER TROUGH IS OVER THE CENTRAL ATLC EXTENDING AN AXIS THROUGH 32N50W TO 26N53W SUPPORTING A SURFACE TROUGH THAT EXTENDS THROUGH 32N48W ALONG 26N51W TO 20N54W. SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS ARE FROM 21N-26N BETWEEN 50W-57W. A BROAD SURFACE RIDGE COVERS THE E ATLC ANCHORED BY A 1027 MB HIGH OVER THE AZORES AND A RIDGE AXIS EXTENDING THROUGH 32N39W TO 25N50W LEAVING THE E ATLC UNDER MOSTLY FAIR CONDITIONS THIS EVENING. W ATLC SURFACE TROUGH WILL LINGER THROUGH SAT. THE SURFACE RIDGE WILL LIFT N BY MON. THE LOW PRESSURE SYSTEM IN THE SPECIAL FEATURES CURRENTLY NEAR 13N35W...POSSIBLY BE TROPICAL CYCLONE...WILL ENTER THE CENTRAL ATLC LATE MON AND SHOULD MOVE INTO THE W ATLC BY TUE. THE SECOND LOW PRESSURE SYSTEM CURRENTLY NEAR 11N24W...POSSIBLY BE TROPICAL CYCLONE...WILL MOVE ACROSS THE W TROPICAL ATLC LATE SAT AND SHOULD MOVE NW OF THE CARIBBEAN BY MON. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ PAW