000 AXNT20 KNHC 172347 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT WED AUG 17 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 2330 UTC. ...SPECIAL FEATURE... AN ACTIVE TROPICAL WAVE IS MOVING THROUGH THE CENTRAL CARIBBEAN EXTENDING S OF JAMAICA WITH AXIS FROM 18N77W TO 12N78W MOVING W 15-20 KT. SATELLITE IMAGERY INDICATES A CLEAR MID-LEVEL CIRCULATION AROUND THE AXIS...BUT A WELL-DEFINED SURFACE CIRCULATION HAS NOT FORMED AT THIS TIME. ENHANCED DEEP LAYER MOISTURE ACCOMPANIES THIS WAVE...ALONG WITH SCATTERED HEAVY SHOWERS AND THUNDERSTORMS FROM 13N-19N BETWEEN 74W-80W. THE SYSTEM CONTINUES TO SHOW SIGNS OF ORGANIZATION AND ENVIRONMENTAL CONDITIONS APPEAR CONDUCIVE FOR A TROPICAL DEPRESSION TO FORM DURING THE NEXT DAY OR TWO. INTERESTS ALONG THE COAST OF THE WESTERN CARIBBEAN SEA SHOULD MONITOR THE PROGRESS OF THIS DISTURBANCE. THIS SYSTEM HAS A HIGH CHANCE OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS AS IT MOVES GENERALLY WESTWARD. ...TROPICAL WAVES... WELL DEFINED TROPICAL WAVE IS ACROSS THE CENTRAL TROPICAL ATLC ALONG 19N33W TO THE MONSOON TROUGH NEAR 13N34W MOVING W 15-20 KT. SATELLITE IMAGERY SHOWS LOW-LEVEL CYCLONIC FLOW AROUND THE WAVE AXIS CONCENTRATED AT THE INTERSECTION WITH THE MONSOON TROUGH. THIS CYCLONIC FLOW WAS ALSO EVIDENT IN EARLIER ASCAT DATA. THE WAVE IS EMBEDDED WITHIN A SURGE OF DEEP LAYER MOISTURE ON TOTAL PRECIPITABLE WATER IMAGERY. ISOLATED MODERATE TO STRONG CONVECTION IS W OF THE WAVE AXIS FROM 12N-15N BETWEEN 36W-39W. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 20N16W SW ACROSS THE CAPE VERDE ISLANDS ALONG 16N24W TO S OF A TROPICAL WAVE NEAR 13N34W TO 8N45W. THE EXTENSION OF THE MONSOON TROUGH HAS DISRUPTED THE CONFLUENCE ALONG THE ITCZ AND THEREFORE WAS NOT ANALYZED ON THE 1800 UTC SURFACE ANALYSIS. HOWEVER...AN AREA OF SCATTERED SHOWERS AND THUNDERSTORMS IS FROM 6N-15N BETWEEN 47W-57W ASSOCIATED WITH AN AREA OF ENHANCED MOISTURE EVIDENT IN TOTAL PRECIPITABLE WATER IMAGERY. ...DISCUSSION... THE GULF OF MEXICO... THE LONGWAVE UPPER LEVEL TROUGH IS NOW OVER THE WEST ATLC. IN ITS WAVE...UPPER LEVEL NE FLOW COVERS THE DISCUSSION AREA THIS EVENING...PROVIDING DRY AIR ALOFT AND SUPPRESSING DEEP CONVECTION ACROSS THE AREA. HOWEVER...AT SURFACE...A WEAK STATIONARY FRONT LINGERS OVER THE NE GULF...ANALYZED FROM 28N83W TO 27N86W TO 29N90W. NO CONVECTION IS IN THE VICINITY OF THE FRONT AS THE IT CONTINUES TO WEAKEN IN THE NEXT 24 HOURS. THE REMAINDER OF THE BASIN IS UNDER THE INFLUENCE OF A WEAK SURFACE RIDGE AROUND A 1017 MB HIGH IN THE NW GULF NEAR 27N94W. THIS FEATURE IS EXPECTED TO REMAIN OVER THE WRN HALF OF THE BASIN DURING THE NEXT 24 HOURS. THE CARIBBEAN SEA... AN UPPER LEVEL INVERTED TROUGH MOVES ACROSS THE FAR NW CARIBBEAN GENERATING WIDELY SCATTERED SHOWERS N OF 18N W OF 82W. AN ACTIVE TROPICAL WAVE IS S OF JAMAICA SUPPORTING SCATTERED HEAVY SHOWERS AND THUNDERSTORMS FROM 13N-19N BETWEEN 74W-80W. SEE SPECIAL FEATURES SECTION ABOVE FOR MORE DETAILS. SCATTER SHOWERS ARE OFF THE IMMEDIATE COAST OF PANAMA AND COSTA RICA ASSOCIATED WITH THE MONSOON TROUGH EXTENDING ACROSS THESE TWO COUNTRIES. MOSTLY FAIR WEATHER CONDITIONS ARE OBSERVED ELSEWHERE WITH A FEW ISOLATED SHOWERS EMBEDDED WITHIN THE TRADE WIND FLOW. EXPECT THE TROPICAL WAVE TO MOVE WWD INTO THE WEST CARIBBEAN BRINGING SIGNIFICANT CONVECTION TO CENTRAL AMERICA THROUGH THE WEEKEND. THE ATLANTIC OCEAN... A LONGWAVE UPPER LEVEL TROUGH MOVES ACROSS THE WEST ATLC GENERATING A LARGE AREA OF SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS N OF 27N BETWEEN 65W-75W. THE UPPER TROUGH ALSO SUPPORTS A FRONTAL BOUNDARY ALONG 32N75W TO THE COAST OF FLORIDA NEAR 29N81W. AN UPPER LEVEL LOW IS CENTERED NEAR 23N57W WITHOUT ANY CONVECTION. THE REMAINDER OF THE BASIN IS DOMINATED BY SURFACE RIDGING AROUND A 1025 MB HIGH NEAR 32N58W AND A 1024 MB HIGH NEAR 33N34W PROVIDING MOSTLY FAIR WEATHER ELSEWHERE ACROSS THE DISCUSSION AREA. SATELLITE IMAGERY CONTINUES TO SHOW TWO AREAS OF AFRICAN DUST. THE FIRST IS E OF 45W WITH CLEARING AROUND THE TROPICAL WAVE ALONG 34W. THE SECOND AREA IS N OF THE CARIBBEAN BETWEEN 60W-74W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ GARCIA