000 AXNT20 KNHC 161805 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT SAT AUG 16 2014 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 1745 UTC. ...TROPICAL WAVES... A TROPICAL WAVE IS MOVING ACROSS THE CAPE VERDE ISLANDS WITH AXIS EXTENDING FROM 17N19W TO 9N19W...MOVING W AT 5 KT. THE WAVE HAS DETACHED FROM A 1012 LOW THAT IS EMBEDDED IN THE MONSOON TROUGH NEAR 10N16W. DEEP LAYER MOISTURE AND MIDDLE TO UPPER LEVEL DIFFLUENCE SUPPORT SCATTERED MODERATE CONVECTION FROM 1N- 15N BETWEEN 17W-29W. A TROPICAL WAVE IS ON THE CENTRAL ATLC WITH AXIS EXTENDING FROM 12N45W TO A 1012 MB LOW NEAR 3N44W TO 2N43W...MOVING W AT 10-15 KT. METEOSAT PSEUDO NATURAL AND SAL TRACKING IMAGERY INDICATE SAHARAN DUST AND DRY AIR IN THE WAVE ENVIRONMENT N OF THE LOW CENTER...WHICH IS SUPPRESSING CONVECTION IN THIS REGION OF THE WAVE. SCATTERED MODERATE CONVECTION IS MOSTLY LIMITED S OF THE MONSOON TROUGH FROM 3S-4N BETWEEN 38W-49W. A TROPICAL WAVE IS ON THE EASTERN CARIBBEAN WITH AXIS EXTENDING FROM 19N87W TO 2N90W...MOVING W AT 20-25 KT. HIGH DEEP LAYER MOISTURE IS ASSOCIATED WITH THIS WAVE WHICH ALONG MIDDLE TO UPPER LEVEL DIFFLUENCE SUPPORT SCATTERED MODERATE/ISOLATED STRONG CONVECTION AND TSTMS FROM 12N-20N BETWEEN 62W-66W AND FROM 11N-14N BETWEEN 63W-67W. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE WEST AFRICAN COAST NEAR 18N16W AND THEN CONTINUES TO A 1012 MB LOW NEAR 15N20W TO 13N30W TO A 1012 MB LOW NEAR 11N36W TO THE EQUATOR ALONG 62W. THE INTERTROPICAL CONVERGENCE ZONE AXIS CONTINUES W NEAR THAT POINT TO THE EQUATOR ALONG 75W. FOR INFORMATION REGARDING CONVECTION SEE THE TROPICAL WAVES SECTION. ...DISCUSSION... GULF OF MEXICO... A WEAK SURFACE RIDGE DOMINATES ACROSS THE GULF WHICH IS PROVIDING VARIABLE WINDS OF 5-10 KT. SOUTHEASTERLY FLOW ASSOCIATED WITH THIS RIDGE CONTINUES TO ADVECT MOISTURE FROM THE CARIBBEAN BASIN WHICH ALONG MIDDLE TO UPPER LEVEL DIFFLUENCE SUPPORT SCATTERED HEAVY SHOWERS AND TSTMS N OF 30N BETWEEN 88W- 92W AND FROM 25N-28N E OF 84W...INCLUDING THE FLORIDA PENINSULA. UPPER LEVEL DIFFLUENCE IN THE SW GULF SUPPORT SCATTERED SHOWERS S OF 21N W OF 93W. FAIR WEATHER IS ELSEWHERE. SURFACE RIDGING IS EXPECTED TO REMAIN IN PLACE ACROSS THE GULF THROUGH MONDAY WITH A HIGH PRESSURE CENTER FORMING EARLY SUNDAY AND PREVAILING ACROSS THE EASTERN BASIN THROUGH EARLY NEXT WEEK. CARIBBEAN SEA... A TROPICAL WAVE ASSOCIATED WITH HIGH DEEP LAYER MOISTURE IS MOVING ACROSS THE EASTERN CARIBBEAN GENERATING SCATTERED HEAVY SHOWERS AND TSTMS ON PUERTO RICO...THE VIRGIN ISLANDS AS WELL AS THE SE CARIBBEAN FROM 11N-15N BETWEEN 63W-68W. A SIMILAR ENVIRONMENT IS ON THE SW BASIN SUPPORTING SCATTERED MODERATE CONVECTION AND ISOLATED TSTMS S OF 15N W OF 80W. SCATTERED SHOWERS ARE S OF 15N W OF 123W. DEEP LAYER DRY AIR ACROSS THE REMAINDER BASIN...SUPPORT FAIR WEATHER. A RELATIVE TIGHT PRESSURE GRADIENT ACROSS THE CENTRAL AND SW CARIBBEAN CONTINUE TO SUPPORT TRADES OF 20-25 KT IN THIS REGION WITH WINDS INCREASING UP TO 30 KT ALONG THE COAST OF COLOMBIA. ELSEWHERE...TRADES OF 10-15 KT DOMINATE. THE TROPICAL WAVE IS FORECAST TO MOVE ACROSS HISPANIOLA SAT NIGHT THROUGH SUN AFTERNOON. ...HISPANIOLA... DEEP LAYER DRY AIR CONTINUES ACROSS THE ISLAND WHICH IS PROVIDING AN OVERALL STABLE ENVIRONMENT. THE DRY SAHARAN AIRMASS WILL CONTINUE TO MOVE ACROSS THE ISLAND THROUGH SATURDAY AFTERNOON THUS SUPPORTING FAIR WEATHER BUT SOME HAZINESS. HOWEVER...A TROPICAL WAVE IS EXPECTED TO MOVE ACROSS THE ISLAND THIS EVENING THROUGH SUN AFTERNOON GENERATING RAINSHOWERS AND TSTMS. ATLANTIC OCEAN... WESTERLY FLOW FROM THE EASTERN GULF IS ADVECTING ABUNDANT MOISTURE INTO THE SW N ATLC WATERS WHICH ALONG A DIFFLUENT ENVIRONMENT SUPPORT SCATTERED HEAVY SHOWERS AND TSTMS N OF 27N BETWEEN 63W-79W. FARTHER EAST...OVER THE EASTERN BASIN A MIDDLE TO UPPER LEVEL TROUGH SUPPORTS A COLD FRONT WHICH TAIL ENTERS THE AREA OF DISCUSSION FROM 30N40W SW TO 28N44W AS WELL AS SCATTERED SHOWERS N OF 29N BETWEEN 44W-59W. OTHERWISE...THE REMAINDER BASIN IS UNDER THE INFLUENCE OF A SURFACE RIDGE ANCHORED BY A 1023 MB HIGH CENTERED NEAR 27N62W AND A 1022 MB HIGH NEAR 26N57W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ NR