000 AXNT20 KNHC 172347 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT MON AUG 17 2015 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... TROPICAL WAVE EXTENDS FROM 09N31W TO 18N33W MOVING W AT 15-20 KT. A 1010 MB LOW IS CENTERED AT THE SOUTHERN EXTENT OF THE WAVE AXIS EMBEDDED WITHIN THE MONSOON TROUGH NEARLY COLLOCATED WITH A MAXIMUM IN 850 MB RELATIVE VORTICITY. SCATTERED MODERATE CONVECTION IS FROM 06N-12N BETWEEN 29W-36W. THE SYSTEM HAS A MEDIUM CHANCE OF DEVELOPING INTO A TROPICAL CYCLONE DURING THE NEXT 48 HOURS. ...TROPICAL WAVES... TROPICAL WAVE EXTENDS FROM 06N51W TO 15N50W MOVING W AT 15 KT. THE WAVE COINCIDES WITH VERY SUBTLE 700 MB TROUGHING BETWEEN 48W- 54W AND REMAINS A RELATIVELY LOW-AMPLITUDE FEATURE AT THIS TIME. ISOLATED MODERATE CONVECTION IS FROM 08N-12N BETWEEN 48W-53W. TROPICAL WAVE EXTENDS FROM 06N81W TO 16N81W MOVING W AT 15 KT. MOST OF THE ENERGY ASSOCIATED WITH THE WAVE IS MOVING OVER PANAMA AND COSTA RICA THIS EVENING GENERATING SCATTERED MODERATE CONVECTION FROM 04N-12N BETWEEN 78W-86W. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 15N17W TO THE SPECIAL FEATURES 1010 MB LOW NEAR 10N32W TO 09N39W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 09N39W TO 06N50W. ASIDE FROM CONVECTION ASSOCIATED WITH THE SPECIAL FEATURES LOW AND TROPICAL WAVE ALONG 51W...ISOLATED MODERATE CONVECTION IS FROM 09N-15N BETWEEN 14W-27W...AND FROM 06N-09N BETWEEN 45W-49W. ...DISCUSSION... GULF OF MEXICO... WATER VAPOR IMAGERY INDICATES A MIDDLE TO UPPER LEVEL LOW CENTERED OVER NE MEXICO NEAR 24N101W THAT CONTINUES TO PROVIDE SOUTH-SOUTHWESTERLY FLOW ALOFT OVER THE GULF W OF 90W THIS EVENING...AND A MAXIMUM IN UPPER LEVEL DIFFLUENCE GENERALLY N OF 24N. THIS DIFFLUENCE ALONG WITH A WEAK SURFACE TROUGH ANALYZED FROM THE LOUISIANA COAST NEAR 30N92W TO 23N95W IS GENERATING SCATTERED SHOWERS AND TSTMS N OF 22N BETWEEN 87W-95W...AND N OF 27N BETWEEN 83W-87W. CONVECTION IS ALSO OCCURRING ACROSS PORTIONS OF THE FLORIDA PENINSULA DUE TO PEAK DAYTIME HEATING... INSTABILITY...AND SEABREEZE DYNAMICS. OTHERWISE...A WEAK SURFACE RIDGE AXIS EXTENDS ACROSS THE CENTRAL FLORIDA PENINSULA TO THE SW GULF WITH MOSTLY GENTLE TO MODERATE SOUTHERLY FLOW PREVAILING THIS EVENING THAT IS EXPECTED THROUGH TUESDAY NIGHT LATE. THEREAFTER...THE S-SE WINDS WILL INCREASE SLIGHTLY ACROSS THE WESTERN GULF AS AN AREA OF LOW PRESSURE DEVELOPS ACROSS THE SOUTHERN PLAINS TUESDAY NIGHT INTO WEDNESDAY. CARIBBEAN SEA... AN UPPER LEVEL ANTICYCLONIC CIRCULATION IS CENTERED OVER THE NORTHERN YUCATAN PENINSULA NEAR 21N88W AND AN UPPER LEVEL LOW IS CENTERED OVER EASTERN CUBA NEAR 20N75W PROVIDING THE WESTERN PORTION OF THE BASIN WITH GENERALLY STABLE NORTH-NORTHWESTERLY FLOW ALOFT. A FEW ISOLATED SHOWERS AND TSTMS ARE OCCURRING ACROSS CUBA THIS EVENING...BUT THIS ACTIVITY WILL MOST LIKELY DIMINISH WITH THE LOSS OF DAYTIME HEATING AND INSTABILITY. THE ONLY EXCEPTION TO CLEAR SKIES AND FAIR CONDITIONS IS A TROPICAL WAVE ANALYZED ALONG 82W THAT IS GENERATING ISOLATED SHOWERS AND TSTMS S OF 12N BETWEEN 79W-86W...INCLUDING PORTIONS OF PANAMA... COSTA RICA...AND NICARAGUA. FARTHER EAST...MORE OF AN INFLUENCE FROM THE UPPER LEVEL LOW IS FELT ACROSS HISPANIOLA IN THE FORM OF SCATTERED SHOWERS AND TSTMS OCCURRING FROM 17N-21N BETWEEN 68W-73W IN THE REGION OF MAXIMUM MIDDLE TO UPPER LEVEL DIFFLUENCE. OTHERWISE...DRY AND STABLE AIR ALOFT IS NOTED S OF 16N OVER THE SOUTH-CENTRAL CARIBBEAN AND THE EASTERN CARIBBEAN E OF 67W PROVIDING FOR MOSTLY CLEAR SKIES AND FAIR CONDITIONS THIS EVENING. ...HISPANIOLA... CURRENTLY...SCATTERED SHOWERS AND TSTMS ARE OCCURRING ACROSS THE ISLAND DUE TO THE PRESENCE OF AN UPPER LEVEL LOW CENTERED OVER EASTERN CUBA NEAR 20N75W. THE ISLAND IS EXPECTED TO REMAIN WITHIN THE REGION OF MAXIMUM MIDDLE TO UPPER LEVEL DIFFLUENCE DURING THE OVERNIGHT PERIOD INTO TUESDAY...RESULTING IN CONTINUED PRECIPITATION...LOCALLY HEAVY AT TIMES...AND THE INCREASED POTENTIAL FOR FLASH FLOODING. ATLANTIC OCEAN... AN UPPER LEVEL RIDGE IS CENTERED OVER THE FLORIDA PENINSULA THIS EVENING AND CONTINUES TO SUPPORT A BROAD AREA OF HIGH PRESSURE ACROSS THE SW NORTH ATLC ANCHORED BY A 1021 MB HIGH CENTERED NEAR 31N75W. WITH A MOSTLY DIFFLUENT ENVIRONMENT ALOFT... SCATTERED SHOWERS AND TSTMS ARE OCCURRING ACROSS THE FLORIDA PENINSULA...INLAND PORTIONS OF GEORGIA...AND THE ADJACENT COASTAL WATERS GENERALLY N OF 28N W OF 79W. TO THE SOUTH...AN UPPER LEVEL LOW IS CENTERED OVER EASTERN CUBA WITH A SURFACE REFLECTION ANALYZED AS A SURFACE TROUGH FROM 22N77W TO 25N76W PROVIDING FOCUS FOR ISOLATED SHOWERS AND TSTMS FROM 23N-25N BETWEEN 76W-79W. IN ADDITION...SCATTERED SHOWERS AND TSTMS ARE OCCURRING WITHIN THE REGION OF MAXIMUM MIDDLE TO UPPER LEVEL DIFFLUENCE BENEATH THE EASTERN PERIPHERY OF THE UPPER LEVEL LOW FROM 19N-21N BETWEEN 68W-73W...INCLUDING INLAND PORTIONS OF HISPANIOLA. FINALLY...THE REMAINDER OF THE CENTRAL AND EASTERN ATLC IS UNDER THE INFLUENCE OF A SURFACE RIDGE ANCHORED BY A 1022 MB HIGH CENTERED NEAR 32N44W AND A SLIGHTLY MORE ROBUST 1027 MB HIGH CENTERED IN THE VICINITY OF THE AZORES NEAR 39N28W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN