000 AXNT20 KNHC 131018 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT MON JUL 13 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 1015 UTC. ...TROPICAL WAVES... A TROPICAL WAVE IS OVER THE E ATLANTIC WITH AXIS EXTENDING FROM 18N21W TO 06N22Z...MOVING W AT 10 TO 15 KT. THE WAVE HAS A WEAK CONVECTIVE AND SURFACE SIGNATURE...BUT IS EVIDENT IN THE TOTAL PRECIPITABLE WATER IMAGERY AND THE GFS-BASED 700 MB TROUGH DIAGNOSTICS. ISOLATED CONVECTION IS E OF THE WAVE AXIS MAINLY S OF 10N AND E OF 23W. A TROPICAL WAVE PREVAILS ACROSS THE CENTRAL ATLANTIC WITH AXIS EXTENDING FROM 19N37W TO 07N37W...MOVING W AT 15 TO 20 KT. THIS WAVE IS EASILY DISTINGUISHED IN IR SATELLITE IMAGERY FROM THE SWIRL OF LOW-LEVEL CLOUDS...A MAXIMUM OF TPW IN THE ENVIRONMENT OF THIS FEATURE...AND IN THE 700 MB TROUGH DIAGNOSTICS. A LARGE AREA OF SAHARAN DUST IS SURROUNDING THIS WAVE...WHICH CONTINUES INHIBITING SIGNIFICANT CONVECTION ALONG THIS WAVE AND MOST OF THE ATLANTIC. A TROPICAL WAVE IS AT ABOUT 50 NM E OF THE WINDWARD ISLANDS WITH AXIS EXTENDING FROM 19N59W TO 07N61W...MOVING W AT AROUND 20 TO 25 KT. THIS WAVE COINCIDES WITH A RELATIVELY BROAD 700 MB TROUGH DEPICTED BY THE GFS MODEL BUT NO CLEAR EVIDENCE AT THE SURFACE. A RELATIVELY DRY AIR PREVAILS IN THE ENVIRONMENT OF THIS WAVE WITH SAHARAN DUST MAINLY N OF 10N HENCE NO SIGNIFICANT CONVECTION IS OBSERVED. A TROPICAL WAVE EXTENDS ACROSS THE W CARIBBEAN WITH AXIS FROM 22N79W TO 09N81W...MOVING W AT 15 TO 20 KT. THIS WAVE IS A LITTLE DIFFICULT TO DEPICT AS THE AREA IS BEING INFLUENCED BY AN UPPER-LEVEL LOW CURRENTLY CENTERED OVER THE SOUTHERN BAHAMAS AND EXTENDING S ACROSS THE W CARIBBEAN. SCATTERED MODERATE CONVECTION IS OBSERVED S OF 16N BETWEEN 72W-84W. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 09N13W TO 10N21W...THEN W OF A TROPICAL WAVE NEAR 09N24W TO 09N35W. THE ITCZ BEGINS NEAR 07N39W TO 09N60W. SCATTERED MODERATE CONVECTION PREVAILS BETWEEN 04N-10N AND E OF 21W. ISOLATED CONVECTION IS DEVELOPING AT AROUND 100 NM N OF THE ITCZ AXIS MAINLY W OF 51W. ...DISCUSSION... GULF OF MEXICO... A 1019 MB SURFACE HIGH IS CENTERED OVER THE NW GULF NEAR 25N94W. WITH THIS...A LIGHT ANTICYCLONIC FLOW PREVAILS ACROSS THE BASIN. ISOLATED CONVECTION IS OBSERVED ACROSS THE E GULF MAINLY E OF 87W AS THE UPPER-LEVEL LOW THAT IS CENTERED OVER SOUTHERN BAHAMAS EXTENDS NW AFFECTING THIS PORTION OF THE BASIN. OVER THE NEXT 24 HOURS...EXPECT FOR THE SURFACE HIGH TO BECOME WEAK AND DISSIPATE. ISOLATED TO SCATTERED CONVECTION IS EXPECTED ONCE AGAIN ACROSS THE E GULF AS THE UPPER-LEVEL LOW PREVAILS ACROSS THE SW ATLANTIC. CARIBBEAN SEA... A TROPICAL WAVE IS MOVING ACROSS THE W CARIBBEAN. FOR MORE INFORMATION PLEASE REFER TO THE SECTION ABOVE. AN UPPER-LEVEL LOW IS CENTERED OVER THE SOUTHERN BAHAMAS NEAR 24N74W AND EXTENDING ITS TROUGH SW ACROSS THE W CARIBBEAN. UPPER-LEVEL DIFFLUENCE PREVAILS E OF THIS FEATURE SUPPORTING SCATTERED LIGHT TO MODERATE CONVECTION ACROSS THE NORTHERN CARIBBEAN WATERS AFFECTING THE GREATER ANTILLES. ANOTHER AREA OF SCATTERED MODERATE CONVECTION IS OBSERVED S OF 16N AFFECTING THE SOUTHERN CARIBBEAN WATERS...CENTRAL AMERICA...AND PORTIONS OF NORTHERN COLOMBIA. SCATTEROMETER DATA DEPICTS LIGHT TO GENTLE TRADES ACROSS THE BASIN EXCEPT BETWEEN 66W-73W WHERE MODERATE WINDS WERE REPORTED. OVER THE NEXT 24 HOURS...LITTLE CHANGE IS EXPECTED TO THE TRADEWINDS. THE UPPER-LEVEL LOW IS EXPECTED TO MOVE SLIGHTLY TO THE NE WHILE THE TROPICAL WAVE CONTINUES MOVING W. THIS LIKELY WILL SHIFT CHANCES FOR DEEP CONVECTION TO THE WESTERN CARIBBEAN. ...HISPANIOLA... A BROAD UPPER-LEVEL LOW IS OVER THE SOUTHERN BAHAMAS AND EXTENDING ACROSS THE W CARIBBEAN. WITH THIS...AN INCREASE IN CLOUDINESS AND CONVECTION IS EXPECTED ONCE AGAIN TODAY. A SIMILAR WEATHER PATTERN WILL PREVAIL AS THE UPPER-LEVEL LOW WILL DRIFT NE OVER THE NEXT 24 HOURS. ATLANTIC OCEAN... THREE TROPICAL WAVES ARE OVER THE TROPICAL ATLANTIC. PLEASE REFER TO THE SECTION ABOVE FOR MORE INFORMATION. AN UPPER-LEVEL LOW IS CENTERED OVER THE SOUTHERN BAHAMAS NEAR 24N74W SUPPORTING ISOLATED CONVECTION ACROSS THE W ATLANTIC MAINLY S OF 27N BETWEEN 63W-77W. TO THE E...A 1025 MB SURFACE HIGH IS CENTERED NEAR 32N39W AND EXTENDING ACROSS THE CENTRAL AND E ATLANTIC WITH FAIR WEATHER. OVER THE NEXT 24 HOURS...EXPECT FOR THE UPPER- LEVEL LOW OVER THE W ATLANTIC TO DRIFT NW ENHANCING CONVECTION. NO CHANGE IS EXPECTED OVER THE REMAINDER OF THE BASIN. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ ERA