000 AXNT20 KNHC 212329 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT WED AUG 21 2013 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. ...TROPICAL WAVES... TROPICAL WAVE IN THE TROPICAL ATLC EXTENDS FROM 19N37W TO 7N38W MOVING W-SW 15-20 KT. WAVE IS ALONG THE LEADING EDGE OF A SURGE OF DEEP MOISTURE AS DEPICTED ON THE TOTAL PRECIPITABLE WATER IMAGERY. A MID LEVEL CYCLONIC CIRCULATION IS THE E OF THE WAVE AXIS. NO ASSOCIATED SHOWERS/CONVECTION. TROPICAL WAVE IN THE CARIBBEAN EXTENDS FROM 21N78W TO 11N78W MOVING W 15-20 KT. WAVE IS EMBEDDED WITHIN A BROAD AREA OF DEEP MOISTURE AS DEPICTED ON THE TOTAL PRECIPITABLE WATER IMAGERY. WAVE IS LOCATED BETWEEN AN UPPER HIGH TO THE E AND AN UPPER LOW TO THE W. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE FROM 14N- 20N BETWEEN 71W-80W. TROPICAL WAVE IN THE GULF OF MEXICO IS NO LONGER DISCERNIBLE AND WAS DROPPED FROM THE ANALYSIS. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE E TROPICAL ATLC NEAR 15N17W AND CONTINUES ALONG 14N29W TO 7N50W WHERE THE ITCZ BEGINS AND CONTINUES INTO SOUTH AMERICA NEAR 6N58W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 7N-10N BETWEEN 42W-46W. ...DISCUSSION... GULF OF MEXICO... AN UPPER RIDGE IS ANCHORED IN THE E PACIFIC REGION EXTENDING A RIDGE AXIS N ACROSS S MEXICO TO OVER THE W GULF FROM VERACRUZ MEXICO TO CENTRAL LOUISIANA. AN UPPER LOW IS CENTERED NEAR HAVANA CUBA AND EXTENDS A TROUGH AXIS TO APALACHEE BAY FLORIDA. A SURFACE TROUGH EXTENDS FROM FLORIDA BAY NEAR 25N81W TO OVER NE FLORIDA NEAR CEDAR KEY GENERATING SCATTERED SHOWERS/ THUNDERSTORMS WITHIN 45 NM EITHER SIDE OF THE TROUGH. CLUSTERS OF SCATTERED SHOWERS/ISOLATED THUNDERSTORMS DOT THE GULF THIS EVENING MAINLY N OF 23N E OF 94W AND S OF 24N W OF 92W. A WEAK SURFACE RIDGE EXTENDS FROM THE W ATLC ACROSS S GEORGIA INTO THE GULF TO NEAR 26N93W. SURFACE RIDGE WILL PERSIST THROUGH MON. CARIBBEAN SEA... AN UPPER LOW IS CENTERED NEAR HAVANA CUBA COVERING THE NW CARIBBEAN N OF 17N W OF 80W. AN UPPER RIDGE IS ANCHORED IN THE CENTRAL CARIBBEAN NEAR 17N77W COVERING THE AREA BETWEEN 70W-80W AND EXTENDING A RIDGE AXIS S OF THE UPPER LOW OVER THE NW CARIBBEAN TO OVER CENTRAL AMERICA. THIS UPPER RIDGE IS PROVIDING DIFFLUENCE ALOFT TO GENERATE SCATTERED SHOWERS/ISOLATED THUNDERSTORMS FROM 11N-15N W OF 80W TO INLAND OVER CENTRAL AMERICA. THE MONSOON TROUGH EXTENDS FROM COLOMBIA NEAR 11N74W TO 10N84W IN COSTA RICA GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS S OF 11N BETWEEN COLOMBIA AND COSTA RICA. A WEAK SURFACE TROUGH IS OVER THE SE CARIBBEAN EXTENDING FROM 14N61W TO TO TRINIDAD GENERATING ISOLATED SHOWERS FROM 11N-14N W OF THE WAVE TO 65W. AFTERNOON THUNDERSTORMS HAVE DEVELOPED INLAND OVER HISPANIOLA...CUBA...AND JAMAICA. TROPICAL WAVE WILL MOVE W ACROSS THE W CARIBBEAN TONIGHT AND THU THE ACROSS THE YUCATAN PENINSULA LATE THU THROUGH FRI. HISPANIOLA... AFTERNOON HEATING HAS GENERATE THUNDERSTORMS ACROSS THE ISLAND THIS EVENING THAT ARE BEGINNING TO MOVE W WITH THE EASTERLY TRADE WINDS INTO THE WINDWARD PASSAGE. THE UPPER RIDGE OVER THE CARIBBEAN COVERS THE W END OF THE ISLAND WHILE AN UPPER TROUGH OVER THE ATLC EXTENDS OVER THE E END GIVING THE ISLAND WESTERLY FLOW ALOFT. DAILY AFTERNOON SHOWERS/THUNDERSTORMS ARE EXPECTED TO DEVELOP DUE TO PEAK DAYTIME HEATING AND INSTABILITY. ATLANTIC OCEAN... A BROAD UPPER RIDGE COVERS THE W ATLC ANCHORED NEAR 29N70W AND PROVIDING DIFFLUNCE ALOFT TO GENERATE SCATTERED SHOWERS/ISOLATED THUNDERSTORMS S OF 30N W OF 78W TO INLAND OVER FLORIDA AND CUBA. A SURFACE RIDGE COVERS THE REMAINDER OF THE W ATLC ANCHORED BY A 1023 MB HIGH NEAR 33N74W. A NARROW UPPER TROUGH EXTENDS INTO THE W/CENTRAL ATLC NEAR 32N53W AND CONTINUES ALONG 24N58W TO 20N70W COVERING A PORTION OF HISPANIOLA. THE REMAINDER OF THE ATLC IS UNDER BENIGN UPPER LEVEL FEATURES WITH A SURFACE RIDGE EXTENDING FROM A 1022 MB HIGH NEAR THE AZORES COVERING THE REMAINDER OF THE ATLC BASIN N OF 20N. A WEAK SURFACE TROUGH IS E OF THE LEEWARD ISLANDS EXTENDING FROM 19N56W TO 14N54W WITH ISOLATED SHOWERS POSSIBLE WITHIN 90 NM EITHER SIDE OF THE TROUGH. THE N PORTION OF CARIBBEAN TROPICAL WAVE WILL MOVE ACROSS THE REMAINDER OF THE FAR SW ATLC AND THEN ACROSS THE STRAITS OF FLORIDA TONIGHT AND THU. SURFACE RIDGE WILL DRIFT S AND WEAKEN THU THROUGH SUN AS A WEAK COLD FRONT APPROACHES THE FAR NW ATLC. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ PAW