000 AXNT20 KNHC 111758 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT SUN AUG 11 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...TROPICAL WAVES... TROPICAL WAVE EXTENDS FROM 12N24W TO 20N23W MOVING W AT 15 KT. THE WAVE COINCIDES WITH A BROAD LOW-LEVEL SURFACE CIRCULATION FOCUSED IN THE VICINITY OF A 1010 MB LOW CENTERED NEAR 12N24W. IN ADDITION...A MID-LEVEL 700 MB TROUGH AXIS ALSO EXTENDS FROM 12N24W NORTHWARD TO ALONG THE WAVE AXIS TO 20N23W. TOTAL PRECIPITABLE WATER IMAGERY INDICATES MAXIMUM VALUES FROM 08N-22N BETWEEN 15W-26W. CONVECTION REMAINS LARGELY EMBEDDED WITHIN THE MONSOON TROUGH AXIS WITH SCATTERED MODERATE FROM 08N-12N BETWEEN 21W-28W. TROPICAL WAVE EXTENDS FROM 07N43W TO 18N47W MOVING W AT 15-20 KT. THE WAVE REMAINS ON THE LEADING EDGE OF SAHARAN DUST WHICH IS NOTED ON VISIBLE SATELLITE IMAGERY TO THE EAST OF THE WAVE AXIS. THIS SAHARAN AIR LAYER IS INHIBITING ANY DEEP CONVECTION AND RESULTING IN ONLY A FEW POSSIBLE SHOWERS IN THE VICINITY OF THE SOUTHERN PORTION OF THE WAVE FROM 04N-09N BETWEEN 40W-48W WHICH REMAINS EMBEDDED WITHIN THE MONSOON TROUGH AXIS. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 18N16W TO 12N24W TO 06N44W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 06N44W TO 05N49W TO 06N57W. ASIDE FROM CONVECTION ASSOCIATED WITH THE TROPICAL WAVE ALONG 24W...WIDELY SCATTERED MODERATE CONVECTION IS FROM 06N-13N BETWEEN 14W-28W. ...DISCUSSION... GULF OF MEXICO... WATER VAPOR IMAGERY INDICATES A MIDDLE TO UPPER LEVEL LOW IS CENTERED OVER THE WESTERN GULF NEAR 23N96W THAT CONTINUES TO CARRY WITH IT MOISTURE GENERALLY W OF 85W. WHILE SURFACE RIDGING REMAINS ANCHORED OVER THE SW NORTH ATLC REGION...MOSTLY E-SE WINDS PREVAIL OVER THE BASIN THIS AFTERNOON. THE EXCEPTION IS THE PRESENCE OF A SURFACE TROUGH ANALYZED FROM THE TEXAS COAST NEAR 28N97W SOUTHWARD INTO A 1013 MB LOW NEAR 21N96W THEN SE TO THE SOUTHERN MEXICO COAST NEAR 18N93W. LOW-LEVEL MOISTURE CONVERGENCE ALONG WITH THE UPPER LEVEL DYNAMICS PROVIDED BY THE WESTWARD MOVING UPPER LEVEL LOW ARE GENERATING SCATTERED SHOWERS AND TSTMS S OF 26N W OF 92W...WITH ISOLATED SHOWERS AND TSTMS OCCURRING ELSEWHERE W OF 86W. THE SURFACE TROUGHING ACROSS THE WESTERN GULF IS EXPECTED TO SLOWLY DRIFT WESTWARD AND DISSIPATE OVER THE NEXT 24 HOURS WITH PRIMARILY E-SE WINDS IN THE RANGE OF 10 TO 20 KT PREVAILING OVER THE GULF THROUGH EARLY TUESDAY. THEREAFTER...A RIDGE AXIS IS FORECAST TO ANCHOR ALONG 27N UNTIL FRIDAY. CARIBBEAN SEA... AN UPPER LEVEL ANTICYCLONIC CIRCULATION IS CENTERED OVER THE WESTERN CARIBBEAN NEAR 14N81W AND IS PROVIDING AN OVERALL DIFFLUENT AND UNSTABLE ATMOSPHERE ALOFT W OF 75W. AT THE SURFACE...E-SE WINDS PREVAIL WITH AREAS OF LOW-LEVEL MOISTURE CONVERGENCE THAT CONTINUE TO GENERATE WIDELY SCATTERED SHOWERS AND ISOLATED TSTMS ACROSS THE NW CARIBBEAN N OF 16N W OF 76W...INCLUDING BELIZE...INLAND PORTIONS OF THE SE YUCATAN PENINSULA...AND NORTHERN GUATEMALA. ACROSS THE SW CARIBBEAN AND PORTIONS OF INLAND CENTRAL AMERICA...THE MOISTURE CONVERGENCE IS MARGINALLY STRONGER WITH SCATTERED SHOWERS AND TSTMS S OF 14N BETWEEN 70W-85W. SOME OF THIS CONVECTION IS LIKELY ENHANCED DUE TO CLOSE PROXIMITY OF THE MONSOON TROUGH AXIS ANALYZED ALONG 10N. FARTHER EAST...AN UPPER LEVEL LOW IS CENTERED N OF HISPANIOLA NEAR 21N72W WITH A TROUGH AXIS EXTENDING E-SE TO 20N64W. PRIMARILY W-NW WINDS ALOFT DOMINATE E OF 80W WITH THE BASE OF THE TROUGH LOCATED OVER THE SE CARIBBEAN NEAR 14N64W. WHILE LOW-LEVEL MOISTURE CONVERGENCE IS GENERATING ISOLATED SHOWERS AND TSTMS BETWEEN 65W-75W...THE MIDDLE TO UPPER LEVEL DYNAMICS BECOME STRONGER E OF 65W...PARTICULARLY A 700 MB TROUGH AXIS EXTENDING FROM 19N63W TO 13N67W...AND ARE GENERATING SCATTERED SHOWERS AND TSTMS 11N-19N BETWEEN 56W-65W. PRECIPITATION HAS PERSISTED ACROSS THE LESSER ANTILLES AND EASTERN CARIBBEAN OVER THE PAST DAY OR SO WITH 24 HOUR PRECIPITATION TOTALS FOR GUADELOUPE REGISTERING 1.71 INCHES AND 0.93 INCHES FOR TRINIDAD COVERING THE 07/1200 UTC TO 08/1200 UTC TIME FRAME. HISPANIOLA... CURRENTLY CONDITIONS REMAINS FAIR THIS EARLY AFTERNOON ACROSS THE ISLAND WITH A FEW ISOLATED SHOWERS OCCURRING MOSTLY IN THE NORTHERN ADJACENT COASTAL WATERS. UPPER LEVEL WINDS ARE NORTHWESTERLY ALOFT AND WATER VAPOR IMAGERY INDICATES A FAIRLY DRY AIRMASS IN PLACE THAT IS EXPECTED TO STAY OVER THE REGION THE NEXT FEW DAYS. HOWEVER WITH E-SE WINDS PERSISTING ACROSS MUCH OF THE CARIBBEAN SEA AND SW NORTH ATLC WATERS THIS AFTERNOON AND EVENING...AND PEAK DAYTIME HEATING AND STABILITY TO OCCUR WITHIN THE NEXT FEW HOURS...SCATTERED SHOWERS AND TSTMS ARE POSSIBLE THROUGH LATE EVENING. ATLANTIC OCEAN... A MIDDLE TO UPPER LEVEL ANTICYCLONIC CIRCULATION IS CENTERED NEAR 30N78W THAT INFLUENCES A LARGE PORTION OF THE SW NORTH ATLC THIS AFTERNOON. THE RIDGING ALOFT CONTINUES TO SUPPORT A SURFACE RIDGE OF HIGH PRESSURE ANCHORED BY A 1022 MB HIGH CENTERED NEAR 29N76W. THE SURFACE RIDGE AXIS EXTENDS WESTWARD TO THE FLORIDA PENINSULA AND EASTWARD INTO THE CENTRAL ATLC. MOSTLY FAIR SKIES AND CONDITIONS ACCOMPANY THIS FEATURE W OF 55W...HOWEVER A FEW ISOLATED SHOWERS CONTINUE TO DRIFT WESTWARD UNDER LIGHT EASTERLY SURFACE FLOW. THE MORE CONCENTRATED SHOWER ACTIVITY IS FOCUSED OVER THE BAHAMAS AND TURKS AND CAICOS ISLANDS S OF 26N BETWEEN 70W-77W THIS AFTERNOON. FARTHER EAST ACROSS THE CENTRAL AND EASTERN ATLC...FAIRLY BENIGN CONDITIONS ARE NOTED ON SATELLITE IMAGERY AS A SURFACE RIDGE DOMINATES. THE RIDGING IS ANCHORED BY A 1026 MB HIGH CENTERED SW OF THE AZORES NEAR 34N33W. THE ONLY COMPROMISE OF THE SURFACE RIDGING IS A SURFACE TROUGH ANALYZED FROM 24N47W TO 28N47W WHICH IS SUPPORTED ALOFT BY AN UPPER LEVEL LOW AND MID-LEVEL SHORTWAVE TROUGHING IN THE VICINITY OF 27N52W. WIDELY SCATTERED SHOWERS AND ISOLATED TSTMS ARE OCCURRING FROM 24N-29N BETWEEN 45W-50W. ALSO OF NOTE...WHILE THE TROPICAL WAVES ARE DISCUSSED IN DETAIL ABOVE...BETWEEN THE WAVES AN AREA OF SAHARAN DUST IS LOCATED GENERALLY N OF 12N BETWEEN 25W-45W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN