000 AXNT20 KNHC 182350 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT SUN AUG 18 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. ...SPECIAL FEATURES... POST-TROPICAL CYCLONE ERIN IS CENTERED NEAR 20.4N 39.8W AT 18/2100 UTC OR ABOUT 1080 MI...1740 KM WNW OF THE CAPE VERDE ISLANDS MOVING WEST AT 7 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1009 MB. MAXIMUM SUSTAINED WIND SPEED IS 30 KT WITH GUSTS TO 40 KT. SAHARAN DRY AIR ENTRAINMENT TO THE SYSTEM ENVIRONMENT CONTINUES TO HINDER DEEP CONVECTION AND ERIN IS NOW A REMNANT LOW. SCATTERED MODERATE CONVECTION IS WITHIN 60 NM OF THE CENTER. PLEASE SEE THE LAST NHC FULL FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT5/WTNT25 KNHC FOR MORE DETAILS. ...TROPICAL WAVES... A TROPICAL WAVE IS OVER THE CAPE VERDE ISLANDS. THE WAVE AXIS EXTENDS FROM 19N22W TO 9N22W MOVING W AT 10 KT. THE WAVE IS POSITIONED JUST E OF A MOIST AREA...AS NOTED ON SSMI IMAGERY. SCATTERED SHOWERS ARE WITHIN 120 NM OF THE WAVE AXIS. A TROPICAL WAVE IS MOVING ACROSS THE LESSER ANTILLES. THE WAVE AXIS EXTENDS FROM 20N61W TO 10N62W MOVING W AT 15 KT. THE WAVE REMAINS EMBEDDED WITHIN A MOIST SSMI ENVIRONMENT. SCATTERED SHOWERS ARE WITHIN 120 NM OF THE WAVE AXIS. A TROPICAL WAVE IS MOVING ACROSS THE WESTERN CARIBBEAN SEA. THE WAVE AXIS EXTENDS FROM CENTRAL CUBA AT 23N79W TO PANAMA AT 9N82W MOVING W AT 20 KT. THE WAVE IS EMBEDDED IN A MODERATLY MOIST SSMI ENVIRONMENT. CLUSTERS OF SCATTERED MODERATE CONVECTION ARE OVER CUBA AND JAMAICA. SCATTERED SHOWERS ARE WITHIN 120 NM OF THE REMAINDER OF THE WAVE AXIS. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH PASSES THROUGH COASTAL GAMBIA NEAR 13N15W TO 7N121W TO 6N30W TO 7N37W. THE ITCZ CONTINUES FROM 7N37W TO 12N50W. ISOLATED MODERATE CONVECTION IS WITHIN 120 NM OF THE MONSOON TROUGH E OF 30W. ...DISCUSSION... GULF OF MEXICO... AS OF 2100 UTC...A SURFACE TROUGH EXTENDS FROM SE LOUISIANA AT 29N91W TO 23N94W TO THE SOUTHERN BAY OF CAMPECHE AT 18N94W. SCATTERED SHOWERS ARE NOW WITHIN 120 NM OF THE TROUGH AXIS. FURTHER E...SCATTERED MODERATE CONVECTION IS OVER THE WEST COAST OF FLORIDA N OF 26N. ELSEWHERE... SCATTERED MODERATE CONVECTION IS OVER THE STRAITS OF FLORIDA...W CUBA...THE YUCATAN CHANNEL... AND THE NORTHERN YUCATAN N OF 19N. IN THE UPPER LEVELS... THE BASE OF AN UPPER LEVEL TROUGH IS OVER THE NW GULF AND E TEXAS WITH STRONG SUBSIDENCE. AN UPPER LEVEL RIDGE IS OVER THE E GULF E OF 92W WITH A CONSIDERABLE AMOUNT OF MOISTURE. EXPECT THE SURFACE TROUGH TO MOVE W OVER THE NEXT 24 HOURS. ALSO EXPECT A TROPICAL WAVE TO MOVE TO THE SE GULF AND THE YUCATAN PENINSULA WITH CONVECTION. CARIBBEAN SEA... A TROPICAL WAVE IS OVER THE WESTERN CARIBBEAN. ANOTHER TROPICAL WAVE IS OVER THE LESSER ANTILLES. SEE ABOVE. SCATTERED MODERATE CONVECTION IS OVER HISPANIOLA. ISOLATED MODERATE CONVECTION IS INLAND OVER CENTRAL AMERICA FROM NICARAGUA TO GUATEMALA. A MONSOON TROUGH EXTENDS FROM N COLOMBIA AT 8N76W TO COSTA RICA AT 10N86W. SCATTERED MODERATE CONVECTION IS FROM 7N-12N BETWEEN 80W- 86W. IN THE UPPER LEVELS AN UPPER LEVEL LOW IS CENTERED OVER THE NW CARIBBEAN NEAR 17N84W. AN UPPER LEVEL HIGH IS CENTERED S OF PUERTO RICO NEAR 16N67W. EXPECT OVER THE NEXT 24 HOURS FOR THE TROPICAL WAVES TO MOVE W AND BE THE DOMINATE WEATHER PRODUCERS. ALSO EXPECT CONTINUED CONVECTION ALONG THE MONSOON TROUGH. HISPANIOLA... SCATTERED MODERATE CONVECTION IS OVER HISPANIOLA MOSTLY DUE TO UPPER LEVEL DIFFLUENCE. MORE CONVECTION IS EXPECTED IN 24 HOURS DUE TO AN APPROACHING TROPICAL WAVE. ATLANTIC OCEAN... A 1024 MB HIGH IS OVER THE W ATLANTIC NEAR 33N64W PRODUCING FAIR WEATHER. ANOTHER 1022 MB HIGH IS OVER THE CENTRAL ATLANTIC NEAR 35N46W WITH MORE FAIR WEATHER. POST-TROPICAL CYCLONE ERIN IS CENTERED NEAR 20.4N 39.8W. SEE ABOVE. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ FORMOSA