000 AXNT20 KNHC 292351 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT MON JUL 29 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... A TROPICAL WAVE...THE REMNANTS OF DORIAN...EXTENDS FROM 15N67W TO 24N64W MOVING W AT 10-15 KT. THE WAVE CORRESPONDS WITH A MID- LEVEL TROUGH ALONG 65W AND A MID-LEVEL VORTICITY MAXIMUM IN THE VICINITY OF 22N67W. WHILE NO SURFACE CIRCULATION IS APPARENT AT THIS TIME...THE DYNAMICS ALOFT CONTINUE TO SUSTAIN SCATTERED MODERATE CONVECTION FROM 20N-25N BETWEEN 64W-69W. ...TROPICAL WAVES... TROPICAL WAVE EXTENDS FROM 10N32W TO 18N34W MOVING W AT 5 KT. THE WAVE AND ENERGY ASSOCIATED WITH IT ARE WRAPPED UP IN A MONSOONAL GYRE FOCUSED AROUND A BROAD AREA OF LOWER PRESSURE NOTED AS A 1014 MB LOW CENTERED NEAR 11N33W ALONG THE MONSOON TROUGH AXIS. CONVECTION REMAINS VERY LIMITED WITH THE WAVE AT THIS TIME...HOWEVER POSSIBLE ISOLATED SHOWERS ARE FROM 05N-11N BETWEEN 28W-35W. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 14N17W TO 11N33W TO 06N40W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 06N40W TO 04N45W TO THE EQUATOR NEAR 49W. SCATTERED MODERATE CONVECTION IS FROM 06N-10N BETWEEN 13W-22W. ...DISCUSSION... GULF OF MEXICO... AN UPPER LEVEL ANTICYCLONIC CIRCULATION INFLUENCES MUCH OF NORTHERN MEXICO...THE SOUTHERN U.S. PLAINS...AND PORTIONS OF THE SE CONUS CENTERED NEAR 31N102W THAT IS PROVIDING MUCH OF THE GULF WITH NORTHEASTERLY FLOW ALOFT N OF 22N. WATER VAPOR IMAGERY ALSO INDICATES THAT THE UPPER LEVEL RIDGE WEAKENS OVER THE SOUTHERN FLORIDA PENINSULA AS A TROUGH AXIS EXTENDS ALONG 79W IN THE SW NORTH ATLC. THE UPPER LEVEL RIDGING IS HOWEVER SUPPORTING A SURFACE RIDGE OF HIGH PRESSRE ANCHORED BY A 1020 MB HIGH CENTERED NEAR 27N85W. ONE EXCEPTION TO THE RIDGE IS A SURFACE TROUGH ANALYZED FROM THE FLORIDA PANHANDLE NEAR 31N87W TO 27N90W IN THE NORTH-CENTRAL GULF. ISOLATED SHOWERS AND TSTMS ARE OCCURRING IN THE VICINITY OF THIS BOUNDARY N OF 26N BETWEEN 85W- 92W. OTHERWISE...THE ONLY OTHER AREAS OF SIGNIFICANT SCATTERED SHOWERS AND TSTMS CURRENTLY ARE OCCURRING OVER INLAND PORTIONS OF THE FLORIDA PENINSULA S OF 29N E OF 82W AND ALONG THE ADJACENT COASTAL WATERS OF WESTERN CUBA S OF 23N E OF 86W. THE SURFACE RIDGE IS FORECAST TO GENERALLY REMAIN NEARLY STATIONARY OVER THE NE GULF THROUGH LATE WEDNESDAY WITH E-SE WINDS PERSISTING ACROSS THE WESTERN GULF IN THE RANGE OF 10-20 KT. CARIBBEAN SEA... AN UPPER LEVEL LOW IS CENTERED OVER THE NW CARIBBEAN NEAR 19N85W AND AN UPPER LEVEL ANTICYCLONIC CIRCULATION IS CENTERED OVER THE SW CARIBBEAN NEAR 14N83W. MOST OF THE ACTIVE WEATHER THIS EVENING IS BEING GENERATING ON THE SOUTHERN PERIPHERY OF THE UPPER LEVEL LOW AND WITHIN THE INFLUENCE OF THE UPPER LEVEL RIDGING WHICH IS PROVIDING A MAXIMUM AREA OF DIFFLUENCE OVER THE WESTERN CARIBBEAN AND PORTIONS OF CENTRAL AMERICA. SCATTERED SHOWERS AND TSTMS ARE OCCURRING S OF 17N BETWEEN 81W-89W... INCLUDING WESTERN PANAMA...COSTA RICA...NICARAGUA...HONDURAS... AND EL SALVADOR. THE SOUTHERN EXTENT OF THIS CONVECTION IS LIKELY ENHANCED BY THE CLOSE PROXIMITY OF THE MONSOON TROUGH ANALYZED ALONG 09N/10N FROM NORTHERN COLOMBIA TO SOUTHERN COSTA RICA. FARTHER EAST...A TROPICAL WAVE EXTENDS ACROSS PUERTO RICO TO 15N67W AND REPRESENTS THE SOUTHERN PORTION OF THE WAVE ASSOCIATED WITH THE REMNANTS OF DORIAN. WATER VAPOR IMAGERY INDICATES A VERY DRY AND STABLE AIR MASS INFLUENCES MUCH OF THE CENTRAL AND EASTERN CARIBBEAN S OF 18N E OF 80W. THIS IS RESULTING IN MOSTLY CLEAR SKIES AND FAIR WEATHER CONDITIONS. THE ONLY EXCEPTIONS ARE LATE AFTERNOON AND EARLY EVENING SCATTERED SHOWERS AND TSTMS OCCURRING PRIMARILY OVER THE ISLANDS OF HISPANIOLA...JAMAICA...AND CUBA. THE ONGOING CONVECTION IS EXPECTED TO DIMINISH OVER THE NEXT FEW HOURS WITH THE LOSS OF PEAK DAYTIME HEATING AND INSTABILITY. HISPANIOLA... CURRENTLY SCATTERED SHOWERS AND TSTMS ARE OCCURRING ACROSS THE ISLAND AND THIS ACTIVITY IS EXPECTED TO WANE DUE TO THE LOSS OF PEAK DAYTIME HEATING AND INSTABLITY OVER THE NEXT FEW HOURS. ON THE SYNOPTIC SCALE...AN UPPER LEVEL LOW IS CENTERED N OF HISPANIOLA NEAR 25N71W THAT IS FORECAST TO SLOWLY DRIFT NORTHWESTWARD DURING THE NEXT FEW DAYS. AS THIS OCCURS...THE ISLAND WILL GRADUALLY FALL WITHIN AN AREA OF SOUTHWESTERLY FLOW ALOFT AND THIS WILL RESULT IN A HIGHER CHANCE FOR AFTERNOON AND EARLY EVENING SHOWERS AND TSTMS THROUGH WEDNESDAY. IN ADDITION...THE REMNANTS OF DORIAN ARE FORECAST TO TRACK NORTH OF THE ISLAND THROUGH WEDNESDAY...WITH SURFACE TROUGHING EXTENDING SOUTHWARD PROVIDING ANOTHER MECHANISM TO INITIATE SHOWERS AND TSTMS. ATLANTIC OCEAN... AN UPPER LEVEL TROUGH AXIS EXTENDS ALONG 79W IN THE SW NORTH ATLC FROM OVER THE CAROLINAS SOUTHWARD TO OVER THE FLORIDA STRAITS. SEABREEZE INTERACTION ACROSS THE FLORIDA PENINSULA AS WELL AS MIDDLE TO UPPER LEVEL DIFFLUENCE IS GENERATING SCATTERED SHOWERS AND TSTMS FROM 23N-28N BETWEEN 76W-83W. ISOLATED SHOWERS AND TSTMS ARE ALSO OCCURRING FARTHER NORTH IN THE SW NORTH ATLC WATERS BETWEEN BERMUDA AND THE EASTERN COASTLINE OF THE U.S... GENERALLY N OF 30N W OF 66W. FARTHER EAST...SURFACE RIDGING REMAINS IN PLACE ACROSS THE REMAINDER OF THE SW NORTH ATLC...HOWEVER AN UPPER LEVEL LOW CENTERED NEAR 25N71W IS PRODUCING ISOLATED SHOWERS AND TSTMS FROM 26N-31N BETWEEN 69W- 73W. OTHERWISE...A TROPICAL WAVE ANALYZED ALONG 66W...THE REMNANTS OF DORIAN...CONTINUES TO PROGRESS WESTWARD ON THE SOUTHERN PERIPHERY OF THE SURFACE RIDGING TO THE NORTH ANCHORED BY A 1025 MB HIGH CENTERED NEAR 33N63W. WIDELY SCATTERED SHOWERS AND TSTMS ARE OCCURRING FROM 20N-26N BETWEEN 63W-69W. FINALLY... ACROSS THE CENTRAL ATLC...A MIDDLE TO UPPER LEVEL LOW IS CENTERED NEAR 23N49W THAT SUPPORTS A WEAK SURFACE TROUGH ANALYZED FROM 16N46W TO 23N42W. POSSIBLE ISOLATED SHOWERS ARE OCCURRING WITHIN 150 NM EITHER SIDE OF THE BOUNDARY. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN