000 AXNT20 KNHC 040544 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT SUN AUG 04 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0515 UTC. ...TROPICAL WAVES... TROPICAL WAVE EXTENDS FROM 09N35W TO 19N34W MOVING W AT 10-15 KT. THE WAVE REMAINS EMBEDDED WITHIN THE MONSOON TROUGH AXIS WITH A MID-LATITUDE SURFACE TROUGH ANALYZED TO THE NW OF THE WAVE FROM 18N40W TO 25N39W. WHILE NEITHER FEATURE EXHIBITS A STRONG SIGNAL ON SATELLITE IMAGERY AND IN GLOBAL MODEL DATA...ENERGY ASSOCIATED WITH EACH ARE FORECAST TO MERGE WITHIN THE NEXT 12 TO 24 HOURS ACROSS THE CENTRAL ATLC AND CONTINUE A WESTWARD MOVEMENT TOWARD THE LESSER ANTILLES REACHING 60W BY MONDAY. THE WAVE IS SURROUNDED BY A LARGE AREA OF SUSPENDED SAHARAN DUST AT THIS TIME WITH NO CONVECTION OCCURRING IN THE VICINITY OF THE WAVE. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH AXIS EXTENDS FROM THE AFRICAN COAST NEAR 13N17W TO 13N26W TO 08N40W TO 06N50W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 06N50W TO 06N53W. SCATTERED MODERATE CONVECTION IS FROM 10N-14N BETWEEN 18W-30W...AND FROM 05N-09N BETWEEN 33W-46W. ...DISCUSSION... GULF OF MEXICO... A MIDDLE TO UPPER LEVEL ANTICYCLONIC CIRCULATION IS CENTERED OVER NORTH TEXAS NEAR 32N98W AND IS PROVIDING THE GULF WITH NORTHEAST TO EASTERLY FLOW ALOFT. WATER VAPOR IMAGERY INDICATES IT REMAINS MODERATELY DRY AND STABLE WITH UPPER LEVEL CONVECTIVE DEBRIS CLOUDINESS COVERING THE NORTHERN GULF N OF 25N THIS EVENING. OTHERWISE AS OF 04/0300 UTC...THE GULF IS UNDER THE INFLUENCE OF A SURFACE RIDGE ANCHORED BY A 1021 MB HIGH CENTERED OVER THE EASTERN GULF NEAR 25N84W. A FEW ISOLATED SHOWERS AND TSTMS ARE OCCURRING S OF 21N OVER THE SW GULF. LOOKING AHEAD... RIDGING WILL DOMINATE OVER THE BASIN THROUGH WEDNESDAY WITH SOUTHERLY WINDS PREVAILING W OF 90W IN THE RANGE OF 10-20 KT. CARIBBEAN SEA... AN UPPER LEVEL ANTICYCLONIC CIRCULATION IS CENTERED OVER THE WESTERN CARIBBEAN NEAR 14N81W THAT IS ADVECTING MOISTURE NORTHWARD ON THE WESTERN PERHIPHERY OF THE RIDGING ACROSS PORTIONS OF CENTRAL AMERICA PRODUCING SCATTERED SHOWERS AND ISOLATED TSTMS S OF 19N W OF 82W. FARTHER SOUTH ACROSS SOUTHERN NICARAGUA...COSTA RICA...AND PANAMA...SCATTERED SHOWERS AND TSTMS ARE OCCURRING DUE TO MAXIMUM UPPER LEVEL DIFFLUENCE AND ALSO THE PRESENCE OF THE MONSOON TROUGH AXIS ANALYZED ALONG 09N/10N FROM NORTHERN COLOMBIA TO SOUTHERN COSTA RICA AND INTO THE EAST PACIFIC REGION. ON THE EASTERN PERIPHERY OF THE UPPER LEVEL ANTICYCLONE...A DRIER NORTHWESTERLY FLOW PREVAILS BETWEEN 70W-80W WITH MOSTLY CLEAR SKIES AND FAIR CONDITIONS. FINALLY... OVER THE EASTERN CARIBBEAN AN UPPER LEVEL LOW IS CENTERED NORTH OF PUERTO RICO NEAR 23N65W PROVIDING TROUGHING E OF 70W. WATER VAPOR IMAGERY INDICATES THE TROUGHING EXHIBITS RELATIVELY DRY AIR ALOFT AND THIS IS RESULTING IN ONLY A FEW ISOLATED LOW- TOPPED SHOWERS OCCURRING N OF 16N BETWEEN 67W-72W...AND E OF 64W...INCLUDING THE LESSER ANTILLES. OTHERWISE...THE SAHARAN AIR LAYER CONTINUES TO PROVIDE A LARGE INFLUENCE TO THE OVERALL STABILITY OF THE BASIN E OF 80W. HISPANIOLA... CURRENTLY A FEW ISOLATED SHOWERS ARE OCCURRING AND WILL REMAIN ACROSS THE ISLAND THROUGH THE OVERNIGHT HOURS. SATELLITE IMAGERY INDICATES THAT THE SAHARAN AIR LAYER WILL PROVIDE AN OVERALL STABLE ATMOSPHERE OVER THE NEXT FEW DAYS. HAZY SKIES ARE EXPECTED DURING THE NEXT 24 TO 48 HOURS. ATLANTIC OCEAN... A NARROW MIDDLE TO UPPER LEVEL TROUGH IS ACROSS THE SW NORTH ATLC W OF 73W THAT SUPPORTS A 1013 MB LOW CENTERED NEAR 32N78W AND A SURFACE TROUGH EXTENDING FROM THE LOW TO 30N80W. GENERALLY AN OVERALL WEAKNESS IN THE SURFACE RIDGING EXTENDING FROM THE CENTRAL ATLC TO THE GULF OF MEXICO...MAXIMUM MIDDLE TO UPPER LEVEL DIFFLUENCE IN THE REGION IS GENERATING EXTENSIVE CLOUDINESS WITH ISOLATED SHOWERS AND TSTMS N OF 25N BETWEEN 74W- 81W. THIS AREA OF TROUGHING...ALONG WITH THE LOW PRESSURE CENTER IS EXPECTED TO MOVE NORTHEAST AND WELL NORTH OF THE DISCUSSION AREA OVER THE NEXT 12 TO 24 HOURS. OTHERWISE THE REMAINDER OF THE SW NORTH ATLC...CENTRAL ATLC...AND EASTERN ATLC ARE UNDER THE INFLUENCE OF A SURFACE RIDGE ANCHORED BY A 1023 MB HIGH CENTERED NEAR 28N63W AND A 1028 MB HIGH CENTERED S-SW OF THE AZORES NEAR 35N30W. EMBEDDED WITHIN THE SOUTHERN PERIPHERY OF THE RIDGE...MID-LATITUDE ENERGY IS ASSOCIATED WITH A SURFACE TROUGH ANALYZED FROM 19N40W TO 25N39W. WHILE NO SIGNIFICANT CONVECTION IS OCCURRING WITH THIS FEATURE...IT IS FORECAST TO MERGE WITH ENERGY ASSOCIATED WITH THE TROPICAL WAVE ALONG 35W OVER THE NEXT 24 HOURS. FINALLY...SAHARAN DUST COVERS MUCH OF THE TROPICAL ATLC AND IS PROVIDING OVERALL STABLE CONDITIONS THIS EVENING. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN