000 AXNT20 KNHC 180600 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT SAT JUL 18 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0515 UTC. ...TROPICAL WAVES... A TROPICAL WAVE IS OVER THE EASTERN ATLC WITH AN AXIS EXTENDING FROM 18N23W TO 09N23W...MOVING W AT AROUND 15 KT. A 1014 MB LOW IS ALONG THE WAVE NEAR 16N23W. SSMI TPW SHOWS HIGH MOISTURE S OF 13N WITH DRIER AIR N OF 13N. ENHANCED METEOSAT IMAGERY INDICATES SAHARAN DUST N OF 14N ALONG THE WAVE. SCATTERED MODERATE TO STRONG CONVECTION IS FROM 07N TO 11N BETWEEN 21W AND 27W. A TROPICAL WAVE IS OVER THE CENTRAL ATLC WITH AN AXIS EXTENDING FROM 20N46W TO 10N47W...MOVING W AT AROUND 15 KT. THIS WAVE IS AT THE LEADING EDGE OF A DEEP LAYER MOISTURE SURGE WITH HIGH MOISTURE NOTED S OF 14N. SCATTERED MODERATE CONVECTION IS FROM 10N TO 14N BETWEEN 43W AND 48W. A TROPICAL WAVE IS OVER THE WESTERN CARIBBEAN SEA WITH AN AXIS EXTENDING FROM 20N82W TO 09N82W...MOVING W AT AROUND 20 KT OVER THE PAST 24 HOURS. THIS WAVE IS EMBEDDED IN AN ENVIRONMENT OF MODERATE TO HIGH MOISTURE. CLUSTERS OF MODERATE CONVECTION ARE FROM 17N TO 21N BETWEEN 78W AND 83W...INCLUDING THE CAYMAN ISLANDS. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 14N17W TO 08N32W. THE ITCZ BEGINS NEAR 09N46W AND CONTINUES TO THE COAST OF S AMERICA NEAR 06N58W. IN ADDITION TO THE CONVECTION ASSOCIATED WITH THE E ATLC TROPICAL WAVE...SCATTERED MODERATE TO STRONG CONVECTION IS FROM 05N TO 10N BETWEEN 27W AND 34W. ...DISCUSSION... GULF OF MEXICO... A BROAD MID TO UPPER LEVEL RIDGE IS CENTERED OVER THE NW GULF NEAR 29N93W WITH A SURFACE HIGH OF 1017 MB CENTERED NEAR 26N89W. WEAKENING ISOLATED MODERATE CONVECTION...ASSOCIATED WITH THE REMNANTS OF A SURFACE TROUGH OVER THE NE GULF COMBINED WITH DEEP TROPICAL MOISTURE...EXTENDS FROM 27N TO 30N BETWEEN 82W AND 90W. E TO SE WINDS IF 10 TO 15 KT COVER THE GULF SE OF THE HIGH. W TO SW WINDS OF AROUND 10 KT ARE NE OF THE HIGH. WEAK TROUGHING IS FORECAST TO PERSIST ACROSS THE NE GULF WHICH WILL CONTINUE TO COMBINE WITH DEEP MOISTURE TO SUPPORT CONVECTION ACROSS THE EASTERN GULF THROUGH SATURDAY. CARIBBEAN SEA... A MID TO UPPER LEVEL TROUGH EXTENDS FROM THE WESTERN ATLC...ACROSS HISPANIOLA...AND TO THE COAST OF CENTRAL AMERICA NEAR THE NICARAGUA/HONDURAS BORDER. UPPER LEVEL DIFFLUENCE ASSOCIATED WITH THE TROUGH AXIS SUPPORTS SCATTERED MODERATE CONVECTION FROM 17N TO 21N BETWEEN 73W AND 76W. OTHER CONVECTION OVER THE NW CARIBBEAN IS PARTIALLY ASSOCIATED WITH A WESTWARD MOVING TROPICAL WAVE. PLEASE SEE THE TROPICAL WAVES SECTION FOR MORE DETAILS. E TO NW TRADE WINDS OF 15 TO 20 KT DOMINATE THE CARIBBEAN. CONVECTION OVER THE W CARIBBEAN WILL GRADUALLY SHIFT INLAND OVER MEXICO AND CENTRAL AMERICA THROUGH SATURDAY AS THE TROPICAL WAVE CONTINUES WESTWARD. ADDITIONAL CONVECTION WILL REMAIN POSSIBLE OVER THE GREATER ANTILLES AND SURROUNDING OFFSHORE WATERS UNDER A DIFFLUENT ENVIRONMENT. SSMI TPW INDICATES DRY AIR SURGING WESTWARD ACROSS THE CENTRAL CARIBBEAN. THIS WILL KEEP CONVECTION TO A MINIMUM E OF 72W OVER THE NEXT 24 HOURS. ...HISPANIOLA... DRY AIR IS SPREADING ACROSS THE ISLANDS FROM THE EAST TONIGHT WITH SOME SAHARAN DUST BEING REPORTED IN SURFACE OBSERVATIONS OVER THE DOMINICAN REPUBLIC. THE BACK EDGE OF DEEP MOISTURE OVER W HAITI SUPPORTS MODERATE CONVECTION W OF 73W OVER HAITI...WHICH SHOULD END OVER THAT PORTION OF THE ISLAND THROUGH THE EARLY MORNING. THE DRY AIR WILL THEN INHIBIT CONVECTION ACROSS THE ISLAND THROUGH SUNDAY. ATLANTIC OCEAN... A PLUME OF MODERATE TROPICAL MOISTURE OVER THE WESTERN ATLC BETWEEN A 1022 MB HIGH CENTERED NEAR 28N65W AND A STATIONARY FRONT N OF OUR AREA OF DISCUSSION SUPPORTS ISOLATED MODERATE CONVECTION AND THUNDERSTORMS FROM 27N TO 31N BETWEEN 64W AND 80W. A SURFACE TROUGH EXTENDS FROM 27N55W TO 22N59W...AS A REFLECTION OF AN UPPER LOW NEAR 23N63W. ISOLATED SHOWERS AND THUNDERSTORMS ARE FROM 23N TO 29N BETWEEN 50W AND 63W. A 1025 MB HIGH CENTERED NEAR 33N28W DOMINATES THE SUBTROPICAL ATLC E OF 48W. TWO TROPICAL WAVES ARE OVER THE TROPICAL NORTHERN ATLC. PLEASE SEE THE TROPICAL WAVES SECTION FOR MORE DETAILS. A 1011 MB LOW IS OVER THE CENTRAL TROPICAL ATLC NEAR 11N41W. SCATTERED MODERATE CONVECTION IS FROM 04N TO 13N BETWEEN 38W AND 44W. CONVECTION WILL CONTINUE S OF THE STATIONARY FRONT OVER THE WESTERN ATLC THROUGH SUNDAY. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ LATTO