000 AXNT20 KNHC 180005 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT FRI JUL 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 2345 UTC. ...TROPICAL WAVES... A TROPICAL WAVE IS OVER THE E ATLC WITH AXIS E OF THE CAPE VERDE ISLANDS NEAR 20W...MOVING W AT 15 KT. THE WAVE IS ASSOCIATED WITH A 1012 MB LOW NEAR 15N20W AND SSMI TPW IMAGERY INDICATE IS EMBEDDED MAINLY IN SHALLOW MOISTURE. METEOSAT RGB AIRMASS...DUST AND SAL TRACKING IMAGERY INDICATE THE PRESENCE OF SAHARAN DRY AIR AND DUST IN THE WAVE ENVIRONMENT...WHICH IS SUPPORTING LACK OF CONVECTION. A TROPICAL WAVE IS OVER THE CENTRAL ATLC WITH AXIS APPROXIMATELY ALONG 45W...MOVING W AT 15 KT. THE WAVE IS AHEAD OF A 1012 MB LOW EMBEDDED IN THE MONSOON NEAR 10N39W. ABUNDANT MOISTURE ASSOCIATED WITH THE LOW AND A DIFFLUENT WIND ENVIRONMENT AT THE MIDDLE LEVELS SUPPORT SCATTERED MODERATE CONVECTION FROM 05N-13N BETWEEN 35W AND 47W. SSMI TPW AND METEOSAT DUST AND SAL TRACKING IMAGERY INDICATE THE PRESENCE OF SAHARAN DRY AIR AND DUST IN THE REMAINDER WAVE ENVIRONMENT THAT ALONG WITH STRONG DEEP LAYER WIND SHEAR HINDER CONVECTION. A TROPICAL WAVE IS OVER THE W CARIBBEAN SEA WITH AXIS NEAR 81W...MOVING W AT 15-20 KT. SSMI TPW INDICATE THE WAVE IS MAINLY EMBEDDED IN A MODERATE MOIST AIRMASS. HOWEVER...STRONG DEEP LAYER WIND SHEAR HINDER CONVECTION. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 12N16W TO 10N25W TO A 1012 MB LOW NEAR 10N39W TO 11N44W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 07N48W TO THE COAST OF GUYANA NEAR 07N58W. ASIDE FROM CONVECTION ASSOCIATED WITH THE TROPICAL WAVE ALONG 45W...SCATTERED MODERATE TO STRONG CONVECTION IS FROM 05N-10N BETWEEN 22W-31W. ...DISCUSSION... GULF OF MEXICO... A BROAD RIDGE COVERING GREAT PORTIONS OF THE ATLC BASIN EXTENDS AN AXIS SW ACROSS THE CENTRAL AND SOUTHERN FLORIDA PENINSULA AND THE GULF OF MEXICO E OF 93W. IN THE GULF...THE RIDGE IS ANCHORED BY A 1018 MB HIGH NEAR 25N87W THAT PROVIDES VARIABLE WINDS OF 5 TO 10 KT ACROSS THE BASIN. A 1013 MB LOW IS OVER NORTHERN FLORIDA EXTENDING A TROUGH ALONG THE PENINSULA TO 26N81W. ABUNDANT MOISTURE BEING ADVECTED FROM THE SE CONUS AND THE SW N ATLC TO THE PENINSULA ALONG WITH DIVERGENT WIND FLOW ALOFT SUPPORT SCATTERED MODERATE CONVECTION AND ISOLATED TSTMS THAT EXTEND TO THE E GULF N OF 25N E OF 89W. THE RIDGE IS FORECAST TO REMAIN NEARLY STATIONARY AND ANCHORED ACROSS THE EAST-CENTRAL GULF WATERS THROUGH LATE SATURDAY. CONVECTION ACROSS THE NE GULF IS EXPECTED TO CONTINUE THROUGH SATURDAY NIGHT. CARIBBEAN SEA... GENERALLY NORTHERLY FLOW ALOFT IS NOTED ON WATER VAPOR IMAGERY W OF 82W ON THE WESTERN PERIPHERY OF AN UPPER LEVEL LOW CENTERED SE OF JAMAICA NEAR 15N75W...S-SW WIND FLOW DOMINATES ACROSS THE E CARIBBEAN E OF 70W ASSOCIATED WITH A BROAD RIDGE OVER THE CENTRAL TROPICAL ATLC. A TROPICAL WAVE IS MOVING ACROSS THE WESTERN BASIN ASSOCIATED WITH A MODERATE MOIST ENVIRONMENT EXTENDING TO THE CENTRAL CARIBBEAN. HOWEVER...STRONG DEEP LAYER WIND SHEAR S OF 18N E OF 82W HINDER THE DEVELOPMENT OF CONVECTION. OVER THE NW CARIBBEAN...BOTH THE MOISTURE AND DIFFLUENT WIND FLOW AT THE MIDDLE LEVELS SUPPORT ISOLATED SHOWERS AND TSTMS N OF 18N W OF 77W...INCLUDING JAMAICA AND CUBA. THIS CONVECTION EXTENDS TO WESTERN HISPANIOLA AND THE WINDWARD PASSAGE. A GENERALLY TIGHT PRESSURE GRADIENT BETWEEN A RIDGE OVER THE ATLC EXTENDING ACROSS THE NORTHERN BASIN AND LOWER PRESSURE OVER COLOMBIA SUPPORT NE TO E WINDS OF 20 KT TO 25 KT FROM 11.5N TO 14N BETWEEN 69W AND 72W. TRADES OF 15 KT DOMINATE ELSEWHERE. THESE WINDS ARE EXPECTED TO PERSIST THROUGH THE UPCOMING WEEKEND GENERALLY BETWEEN 70W-80W. ...HISPANIOLA... MODERATE MOISTURE ASSOCIATED WITH THE PASSAGE OF A TROPICAL WAVE CURRENTLY OVER THE W CARIBBEAN COVERS THE WESTERN PORTION OF THE ISLAND. AT THE MIDDLE LEVELS...A RIDGE ANCHORED OVER THE SW N ATLC AND AN INVERTED TROUGH ALONG 77W GENERATE DIFFLUENT WIND FLOW ACROSS WESTERN DOMINICAN REPUBLIC...HAITI AND THE WINDWARD PASSAGE...THUS SUPPORTING A CLUSTER OF MODERATE CONVECTION AND ISOLATED TSTMS. THIS OVERALL SYNOPTIC REGIME IS EXPECTED TO PERSIST AND GENERATE CONVECTION THROUGH SATURDAY MORNING. ATLANTIC OCEAN... AN MIDDLE TO UPPER LEVEL TROUGH N OF THE AREA OF DISCUSSION CONTINUE TO SUPPORT A STATIONARY FRONT...WHICH ASSOCIATED MOISTURE ADVECTS ACROSS THE SW N ATLC WATERS WHERE IT CONVERGES WITH MOISTURE INFLOW FROM THE NW CARIBBEAN WATERS...THUS ENHANCING ISOLATED SHOWERS AND TSTMS N OF 23N W OF 66W. THE REMAINDER OF THE CENTRAL AND EASTERN ATLC IS UNDER THE INFLUENCE OF A SURFACE RIDGE ANCHORED BY A 1022 MB HIGH CENTERED NEAR 26N64W AND A 1022 MB HIGH CENTERED NEAR 32N47W. HIGH PRESSURE AND RIDGING WILL CONTINUE TO BE THE MAIN FEATURE ACROSS THE BASIN DURING THE NEXT TWO DAYS. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ NR