000 AXNT20 KNHC 131745 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...TROPICAL WAVES... AN EASTERN ATLC TROPICAL WAVE HAS AN AXIS THAT EXTENDS FROM 19N31W TO 09N32W...MOVING W AT 10 TO 15 KT OVER THE PAST 24 HOURS. A LARGE MID LEVEL GYRE NEAR 10N31W ACCOMPANIES THIS WAVE. MUCH OF THIS WAVE IS EMBEDDED IN DRY AIR N OF 09N. ISOLATED MODERATE CONVECTION IS FROM 05N TO 08N BETWEEN 31W AND 35W. A CENTRAL ATLC TROPICAL WAVE HAS AN AXIS THAT EXTENDS FROM 17N51W TO 06N54W...MOVING W AT 10 TO 15 KT OVER THE PAST 24 HOURS. A 700 MB INVERTED TROUGH IS EVIDENT BETWEEN 51W AND 59W. A SURGE OF DEEP MOISTURE ACCOMPANIES THIS WAVE. SCATTERED MODERATE CONVECTION IS WITHIN 200 NM E OF THE WAVE AXIS S OF 15N. A WESTERN CARIBBEAN TROPICAL WAVE EXTENDS FROM 19N81W TO 08N81W...MOVING W AT 15 TO 20 KT OVER THE PAST 24 HOURS. A BROAD 700 MB TROUGH IS INDICATED BETWEEN 78W AND 87W. THIS WAVE IS EMBEDDED IN AN ENVIRONMENT OF MODERATE MOISTURE. ISOLATED MODERATE CONVECTION IS FROM 09N TO 16N BETWEEN 78W AND 85W. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH PASSES THROUGH COASTAL AFRICA NEAR 14N17W TO 09N30W. THE ITCZ BEGINS W OF A TROPICAL WAVE NEAR 08N33W AND CONTINUES TO 07N52W. OTHER THAN CONVECTION ASSOCIATED WITH THE EASTERN ATLC TROPICAL WAVE...ISOLATED MODERATE CONVECTION IS FROM 06N TO 09N BETWEEN 37W AND 50W. ...DISCUSSION... ...THE GULF OF MEXICO... ANTICYCLONIC UPPER LEVEL FLOW COVERS THE WESTERN GULF WHILE AN UPPER TROUGH EXTENDS ALONG THE EASTERN US COAST TO N FL TO THE EXTREME EASTERN GULF TO AROUND 16N. THIS TROUGH SUPPORTS A STATIONARY FRONT THAT EXTENDS ACROSS CENTRAL FLORIDA NEAR 30N82W...ACROSS THE NE GULF...TO LOUISIANA NEAR 30N90W. A PRE- FRONTAL SURFACE TROUGH EXTENDS FROM 29N82W TO 28N96W. ISOLATED MODERATE CONVECTION IS FROM 27N TO 29N BETWEEN 93W AND 96W. CLOSER TO THE BASE OF THE UPPER TROUGH AND UPPER LEVEL DIFFLUENCE...SCATTERED THUNDERSTORMS ARE OVER THE NE GULF FROM 25N TO 29N BETWEEN 82W AND 91W. GENTLE TO MODERATE SURFACE WINDS COVER THE GULF BASIN. OVER THE NEXT 24 HOURS CONVECTION WILL CONTINUE PRIMARILY ALONG AND S OF THE SURFACE TROUGH. THE STATIONARY FRONT WILL DISSIPATE THROUGH TONIGHT. ...THE CARIBBEAN SEA AND HISPANIOLA... A BROAD UPPER LEVEL LOW IS CENTERED NEAR 19N78W OVER THE NORTHERN CARIBBEAN. FLOW AROUND THIS UPPER LOW DOMINATES THE CARIBBEAN BASIN. DYNAMIC LIFT AROUND THE CENTER OF THE UPPER LOW SUPPORTS ISOLATED MODERATE CONVECTION FROM 17N TO 22N BETWEEN 73W AND 87W. A TROPICAL WAVE IS OVER THE WESTERN CARIBBEAN. PLEASE REFER TO THE TROPICAL WAVES SECTION FOR MORE DETAILS. THE UPPER LOW SUPPORTS A SURFACE TROUGH THAT EXTENDS FROM 18N73W TO 13N72W. NO DEEP CONVECTION IS NOTED WITH THIS TROUGH. THE PRESSURE GRADIENT BETWEEN HIGH PRESSURE OVER THE WESTERN ATLC AND LOW PRESSURE OVER COLOMBIA SUPPORTS MODERATE TO FRESH TRADE WINDS OVER THE CENTRAL CARIBBEAN...WITH A SMALL AREA OF STRONG TRADE WINDS NEAR THE COAST OF COLOMBIA BETWEEN 74W TO 76W. GENTLE TO MODERATE TRADE WINDS ARE OCCURRING ELSEWHERE OVER THE CARIBBEAN. OVER THE NEXT 24 HOURS THE WESTERN CARIBBEAN TROPICAL WAVE WILL MOVE INLAND OVER CENTRAL AMERICA. CONVECTION AHEAD OF A TROPICAL WAVE OVER THE CENTRAL CARIBBEAN WILL BEGIN TO AFFECT THE LEEWARD ISLANDS FRIDAY MORNING. THE ATLANTIC OCEAN... AN UPPER TROUGH ALONG THE EASTERN US COAST SUPPORTS A COLD FRONT N OF OUR AREA THAT TRANSITIONS TO A STATIONARY FRONT FROM 31N80W TO N FL. THE COMBINATION OF PRE-FRONTAL FORCING AND UPPER LEVEL DIFFLUENCE SUPPORTS CLUSTERS OF MODERATE CONVECTION AND SCATTERED THUNDERSTORMS FROM 24N TO 31N BETWEEN 75W AND THE FL PENINSULA...AND ISOLATED MODERATE CONVECTION FROM 28N TO 31N BETWEEN 69W AND 75W. FARTHER EAST...A BROAD UPPER LOW CENTERED NEAR 27N57W HAS A SURFACE REFLECTION IN THE FORM OF A SURFACE TROUGH THAT EXTENDS FROM 30N54W TO 24N40W. ISOLATED MODERATE CONVECTION IS FROM 26N TO 31N BETWEEN 51W AND 58W. A NON TROPICAL LOW VOID OF CONVECTION IS CENTERED OFF THE AFRICAN COAST NEAR 25N20W WITH A SURFACE TROUGH EXTENDING FROM 28N18W TO 19N20W. TWO TROPICAL WAVES ARE OVER THE TROPICAL NORTHERN ATLC. PLEASE REFER TO THE TROPICAL WAVES SECTION FOR MORE DETAILS. OVER THE NEXT 24 HOURS CONVECTION WILL CONTINUE AS THE STATIONARY FRONT TRANSITIONS TO A SURFACE TROUGH OFFSHORE OF N FL. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ LATTO