000 AXNT20 KNHC 132326 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT THU AUG 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...TROPICAL WAVES... AN E ATLANTIC TROPICAL WAVE HAS AN AXIS THAT EXTENDS FROM 19N33W TO 09N33W...MOVING W AT 10 KT OVER THE PAST 24 HOURS. A LARGE MID-LEVEL GYRE CURRENTLY CENTERED NEAR 17N35W ACCOMPANIES THIS WAVE. NO CONVECTION IS OBSERVED IN THE VICINITY OF THIS WAVE AS IT CONTINUES IN AN AREA WHERE A BROAD DRY AIRMASS PREVAILS. A TROPICAL WAVE IS MOVING ACROSS THE CENTRAL ATLANTIC WITH AXIS EXTENDING FROM 15N54W TO 07N56W...MOVING W AT 10 TO 15 KT OVER THE PAST 24 HOURS. THIS WAVE IS NOT ONLY NOTICEABLE AT 700 MB BUT ALSO AT THE SURFACE...AS SEEN IN SCATTEROMETER WINDS... SURFACE OBSERVATIONS...AND VISIBLE SATELLITE IMAGERY. A SURGE OF DEEP MOISTURE ACCOMPANIES THIS WAVE...SUPPORTING SCATTERED MODERATE CONVECTION FROM 10N-15N BETWEEN 52W-57W. A TROPICAL WAVE CONTINUES OVER THE W CARIBBEAN WITH AXIS EXTENDING FROM 19N82W TO 08N82W...MOVING W AT 15 TO 20 KT OVER THE PAST 24 HOURS. A SUBTLE 700 MB TROUGH IS OBSERVED 80W-90W AND ABUNDANT MOISTURE SURROUNDS THIS WAVE AND PREVAILS ACROSS THE WHOLE W CARIBBEAN. AN UPPER-LEVEL LOW IS CENTERED W OF JAMAICA NEAR 19N79W SUPPORTING SCATTERED MODERATE CONVECTION ACROSS THE W CARIBBEAN AND HENCE SURROUNDING THIS WAVE MAINLY W OF 80W. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH PASSES THROUGH COASTAL AFRICA NEAR 15N17W TO 09N31W. THE ITCZ BEGINS W OF A TROPICAL WAVE NEAR 09N34W AND CONTINUES TO 09N52W. OTHER THAN CONVECTION ASSOCIATED WITH THE TROPICAL WAVE ALONG 54W...ISOLATED MODERATE CONVECTION IS FROM 06N-08N BETWEEN 47W-50W. ...DISCUSSION... ...GULF OF MEXICO... AN ANTICYCLONIC UPPER-LEVEL FLOW COVERS THE WESTERN GULF WHILE AN UPPER-LEVEL TROUGH EXTENDS ALONG THE EASTERN US COAST TO N FL REACHING THE EXTREME EASTERN GULF E OF 86W. THIS TROUGH SUPPORTS A STATIONARY FRONT THAT EXTENDS FROM THE GULF COAST STATES ACROSS THE FLORIDA PANHANDLE AND THEN INTO THE W ATLANTIC ALONG 30N. A PRE-FRONTAL SURFACE TROUGH PREVAILS ALONG AND IN THE VICINITY OF THE SURFACE TROUGH MAINLY N OF 27N. AN AREA OF UPPER- LEVEL DIFFLUENCE PREVAILS ACROSS THE E GULF REACHING THE FLORIDA PENINSULA SUPPORTING SCATTERED MODERATE CONVECTION MAINLY E OF 84W. TO THE SW...A 1018 MB SURFACE HIGH IS CENTERED NEAR 23N93W WHICH SUPPORTS A LIGHT TO GENTLE ANTICYCLONIC FLOW ACROSS THE BASIN. OVER THE NEXT 24 HOURS...CONVECTION WILL CONTINUE PRIMARILY ALONG AND S OF THE SURFACE TROUGH. THE STATIONARY FRONT IS EXPECTED TO DISSIPATE TONIGHT. CARIBBEAN SEA... A BROAD UPPER-LEVEL LOW IS CENTERED NEAR 19N79W SUPPORTING SCATTERED MODERATE CONVECTION ACROSS THE W CARIBBEAN MAINLY W OF 81W. A TROPICAL WAVE IS OVER THE WESTERN CARIBBEAN. PLEASE REFER TO THE TROPICAL WAVES SECTION FOR MORE DETAILS. A STRONG DEEP LAYER WIND SHEAR PREVAILS ACROSS THE CENTRAL AND E CARIBBEAN WITH NO SIGNIFICANT CONVECTION OBSERVED AT THIS TIME. SCATTEROMETER DATA DEPICTS GENTLE TO MODERATE TRADES PREVAILING ACROSS THE BASIN WITH AN AREAS OF MODERATE TO FRESH WINDS S OF 14N BETWEEN 68W-76W. OVER THE NEXT 24 HOURS THE WESTERN CARIBBEAN TROPICAL WAVE WILL MOVE INLAND OVER CENTRAL AMERICA. THE NEXT TROPICAL WAVE WILL APPROACH THE LESSER ANTILLES ON FRIDAY WITH CONVECTION. ...HISPANIOLA... THE UPPER LEVEL-LOW CENTERED ACROSS THE W CARIBBEAN IS SUPPORTING SCATTERED MODERATE CONVECTION ACROSS THE ISLAND. THIS ACTIVITY WILL CONTINUE THROUGH THE EVENING HOURS. A SIMILAR WEATHER REGIME WILL PREVAIL OVER THE NEXT 24 HOURS. ATLANTIC OCEAN... TWO TROPICAL WAVES ARE IN THE TROPICAL ATLANTIC. PLEASE REFER TO THE SECTION ABOVE FOR MORE DETAILS. AN UPPER-LEVEL TROUGH ALONG THE EASTERN US COAST SUPPORTS A FRONTAL SYSTEM...ANALYZED AS A STATIONARY FRONT FROM THE GULF STATES COAST...NORTHERN FLORIDA...AND THE W ATLANTIC NEAR 31N79W...THEN AS A COLD FRONT FROM 31N79W TO 34N72W. SCATTERED MODERATE CONVECTION PREVAILS IN THE VICINITY OF THESE BOUNDARIES W OF 68W. TO THE E...A SURFACE TROUGH WAS ANALYZED FROM 29N55W TO 26N44W. ISOLATED CONVECTION PREVAILS ALONG THIS BOUNDARY. THE REMAINDER OF THE BASIN IS UNDER THE INFLUENCE OF A SURFACE HIGH THAT EXTENDS S FROM THE NE ATLANTIC. A WEAK 1012 MB SURFACE LOW IS LOCATED NEAR 24N20W WITH NO SIGNIFICANT CONVECTION. OVER THE NEXT 24 HOURS...CONVECTION WILL CONTINUE ACROSS THE W ATLANTIC AS THE FRONTAL BOUNDARIES TRANSITION INTO A SURFACE TROUGH AND PREVAILS IN THE AREA. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ ERA