000 AXNT20 KNHC 181143 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0915 UTC. ...TROPICAL WAVES... A TROPICAL WAVE IS OVER THE EASTERN ATLC WITH AN AXIS EXTENDING FROM 17N25W TO 09N26W...MOVING W AT AROUND 15 KT. A 1014 MB LOW IS ALONG THE WAVE NEAR 14N25W. SSMI TPW SHOWS HIGH MOISTURE S OF 12N WITH DRIER AIR N OF 12N. ENHANCED METEOSAT IMAGERY INDICATES SAHARAN DUST N OF 14N ALONG THE WAVE. SCATTERED MODERATE CONVECTION IS FROM 06N TO 11N BETWEEN 24W AND 28W. A TROPICAL WAVE IS OVER THE CENTRAL ATLC WITH AN AXIS EXTENDING FROM 20N48W TO 10N49W...MOVING W AT AROUND 20 KT OVER THE PAST 24 HOURS. THIS WAVE IS AT THE LEADING EDGE OF A DEEP LAYER MOISTURE SURGE WITH HIGH MOISTURE NOTED S OF 14N. ISOLATED MODERATE CONVECTION IS FROM 10N TO 13N BETWEEN 46W AND 50W. A TROPICAL WAVE IS OVER THE WESTERN CARIBBEAN SEA WITH AN AXIS EXTENDING FROM 20N83W TO 09N83W...MOVING W AT AROUND 15 KT OVER THE PAST 24 HOURS. THIS WAVE IS EMBEDDED IN AN ENVIRONMENT OF MODERATE TO HIGH MOISTURE. SCATTERED MODERATE CONVECTION IS WITHIN 75 NM OF THE WAVE AXIS. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 14N17W TO 07N35W. THE ITCZ BEGINS NEAR 09N45W AND CONTINUES TO THE COAST OF S AMERICA NEAR 06N59W. IN ADDITION TO THE CONVECTION ASSOCIATED WITH THE E ATLC TROPICAL WAVE...CLUSTERS OF MODERATE TO STRONG CONVECTION ARE FROM 03N TO 11N BETWEEN 28W AND 35W. ...DISCUSSION... GULF OF MEXICO... A BROAD MID TO UPPER LEVEL RIDGE REMAINS CENTERED OVER THE NW GULF NEAR 29N93W WITH A SURFACE HIGH OF 1017 MB CENTERED NEAR 26N89W. A SURFACE TROUGH EXTENDS OVER THE NE GULF FROM N FL NEAR 30N83W TO 29N88W. SCATTERED THUNDERSTORMS ARE FROM 26N TO 20N BETWEEN 83W AND 88W. ANOTHER SURFACE TROUGH IS OVER THE SW GULF FROM 22N92W TO 17N93W. THE COMBINATION OF THIS SURFACE TROUGH AND UPPER LEVEL DIFFLUENCE BETWEEN THE RIDGE OVER THE NW GULF AND ANOTHER RIDGE OVER THE E PACIFIC SUPPORTS CLUSTERS OF THUNDERSTORMS S OF 22N W OF 94W. E TO SE WINDS IF 10 TO 15 KT COVER THE GULF SE OF THE SURFACE 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 TONIGHT. 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 20N BETWEEN 74W AND 81W. 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 NE TRADE WINDS OF 15 TO 20 KT DOMINATE THE CARIBBEAN. CONVECTION WILL REMAIN POSSIBLE OVER THE NORTH- CENTRAL AND NW CARIBBEAN UNDER A DIFFLUENT ENVIRONMENT ALOFT THROUGH TONIGHT. SSMI TPW INDICATES DRY AIR SURGING WESTWARD ACROSS THE CENTRAL CARIBBEAN. THIS WILL KEEP CONVECTION TO A MINIMUM E OF 74W OVER THE NEXT 24 HOURS. ...HISPANIOLA... DRY AIR IS SPREADING ACROSS THE ISLANDS FROM THE EAST THIS MORNING WITH SAHARAN DUST BEING REPORTED IN SURFACE OBSERVATIONS OVER THE DOMINICAN REPUBLIC. THIS DRY AIR WILL INHIBIT CONVECTION ACROSS THE ISLAND TODAY AND POSSIBLY THROUGH SUNDAY. ATLANTIC OCEAN... A PLUME OF MODERATE TROPICAL MOISTURE OVER THE WESTERN ATLC BETWEEN A 1021 MB HIGH CENTERED NEAR 28N65W AND A STATIONARY FRONT N OF OUR AREA OF DISCUSSION SUPPORTS SCATTERED MODERATE CONVECTION AND THUNDERSTORMS FROM 27N TO 31N BETWEEN 66W AND 75W. A SURFACE TROUGH EXTENDS FROM 28N53W TO 22N59W...AS A REFLECTION OF AN UPPER LOW NEAR 25N57W. ISOLATED SHOWERS AND THUNDERSTORMS ARE FROM 23N TO 29N BETWEEN 53W AND 64W. A 1023 MB HIGH CENTERED NEAR 30N34W DOMINATES THE SUBTROPICAL ATLC E OF 50W. TWO TROPICAL WAVES ARE OVER THE TROPICAL NORTHERN ATLC. PLEASE SEE THE TROPICAL WAVES SECTION FOR MORE DETAILS. A 1012 MB LOW IS OVER THE CENTRAL TROPICAL ATLC NEAR 11N42W. SCATTERED MODERATE CONVECTION IS FROM 03N TO 13N BETWEEN 38W AND 45W. 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