000 AXNT20 KNHC 071109 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT FRI AUG 07 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 CENTRAL ATLC TROPICAL WAVE EXTENDS FROM 16N44W TO 09N41W MOVING W AT 15 TO 20 KT OVER THE PAST 24 HOURS. THE WAVE COINCIDES WITH A BROAD 700 MB TROUGH BETWEEN 37W AND 47W. DEEP MOISTURE IS CONFINED S OF 12N ALONG THE ENVIRONMENT OF THE WAVE. ISOLATED MODERATE CONVECTION IS FROM 08N TO 10N BETWEEN 39W AND 43W. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH AXIS EXTENDS FROM THE AFRICAN COAST NEAR 18N16W THROUGH A 1011 MB LOW NEAR 11N32W TO 08N46W...WHERE THE ITCZ BEGINS AND CONTINUES TO THE S AMERICA COAST NEAR 09N61W. ISOLATED MODERATE CONVECTION IS WITHIN 100 NM OF THE MONSOON TROUGH AND ITCZ W OF 36W. ...DISCUSSION... GULF OF MEXICO... A SHORTWAVE TROUGH OVER THE EASTERN US HAS AN AXIS THAT EXTENDS SW OVER THE NE GULF THIS MORNING. THE ENHANCED LIFT ASSOCIATED WITH THE TROUGH IS SUPPORTING SCATTERED SHOWERS FROM 29N TO THE N GULF COAST BETWEEN 83W AND 88W. THE SHORTWAVE WILL SHARPEN ALONG THE EASTERN US TODAY AS A FRONTAL SYSTEM NEARS THE NE GULF. THE APPROACH OF THIS FRONT WILL HELP TO SUPPORT CONVECTION OVER THIS PORTION OF THE BASIN TODAY AND TONIGHT. ELSEWHERE...GENERALLY FAIR WEATHER COVERS THE GULF BASIN THIS MORNING. A SURFACE RIDGE AXIS EXTENDS FROM THE W ATLC TO S FL TO NE MEXICO ALONG THE W GULF COAST. A CONVECTION FREE DIURNAL SURFACE TROUGH EXTENDS FROM 23N92W TO 18N94W OVER THE SW GULF. MAINLY GENTLE TO MODERATE ANTICYCLONIC SURFACE WINDS COVER THE GULF OF MEXICO...WITH THE STRONGER WINDS OVER THE WESTERN GULF. CARIBBEAN SEA... AN UPPER LEVEL ANTICYCLONE CENTERED OVER THE SW CARIBBEAN DOMINATES MUCH OF THE CARIBBEAN. DRY AIR AND SUBSIDENCE COVERS THE BASIN E OF 80W S OF 16N AS NOTED IN THE LATEST WATER VAPOR IMAGERY. ALSO NOTED IN WATER VAPOR IMAGERY IS AN AREA OF DYNAMIC LIFT WITH ENHANCED MID LEVEL MOISTURE BETWEEN THE UPPER LEVEL ANTICYCLONE OVER THE CARIBBEAN...AND AN UPPER LEVEL LOW OVER THE CENTRAL ATLC. THE ENHANCED LIFT AND MOISTURE SUPPORTS ISOLATED MODERATE CONVECTION FROM 18N TO 21N BETWEEN 74W AND 81W. THE REMAINDER OF THE CARIBBEAN IS FREE OF DEEP CONVECTION. THE PRESSURE GRADIENT BETWEEN W ATLC SURFACE RIDGING AND LOW PRESSURE OVER COLOMBIA SUPPORTS FRESH TO STRONG TRADE WINDS OVER THE S CENTRAL CARIBBEAN S OF 16N BETWEEN 69W AND 77W. GENTLE TO MODERATE TRADE WINDS COVER THE REMAINDER OF THE BASIN. OVER THE NEXT 24 HOURS CONVECTION WILL REMAIN POSSIBLE OVER THE NW CARIBBEAN...WHERE BETTER MOISTURE AND LIFT WILL REMAIN. SHOWERS AND CHANCES FOR CONVECTION WILL ALSO INCREASE TODAY OVER THE NORTHERN LESSER ANTILLES AND VIRGIN ISLANDS AS A WEAK LOW AND ACCOMPANYING SURFACE TROUGH MOVES NW FROM THE CENTRAL ATLC OVER THE ISLANDS. ...HISPANIOLA... MODERATE MOISTURE COMBINED WITH A BAND OF DYNAMIC LIFT BETWEEN AN UPPER LOW OVER THE CENTRAL ATLC AND UPPER LEVEL RIDGING OVER THE SW CARIBBEAN SUPPORTS ISOLATED MODERATE CONVECTION OVER SW HAITI THIS MORNING. ADDITIONAL THUNDERSTORMS ARE FORECAST TO DEVELOP THIS AFTERNOON ACROSS THE ISLAND WITH THE DAYTIME HEATING. A SURFACE TROUGH MOVING ACROSS THE LESSER ANTILLES TODAY MAY AFFECT HISPANIOLA BY SATURDAY WITH ENHANCED SHOWER AND THUNDERSTORM ACTIVITY. ATLANTIC OCEAN... A MID TO UPPER LEVEL SHORTWAVE TROUGH ABOUT TO EMERGE OFF THE EASTERN US COAST IS SUPPORTING SCATTERED THUNDERSTORMS N OF 28N BETWEEN 74W AND 80W. A SURFACE RIDGE DOMINATES THE MAJORITY OF THE SUBTROPICAL N ATLC ANCHORED BY A 1026 MB HIGH CENTERED NEAR 39N38W. THE RIDGE AXIS EXTENDS SW ACROSS THE W ATLC THROUGH A 1017 MB HIGH CENTERED NEAR 28N72W...AND CONTINUES W TO S FL. AN UPPER LOW CENTERED NEAR 26N61W SUPPORTS A WEAKNESS IN THE SURFACE RIDGE WITH A 1015 MB LOW CENTERED NEAR 27N60W. A SURFACE TROUGH EXTENDS FROM 31N60W THROUGH THE LOW CENTER TO 22N60W. A BROAD AREA OF SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS EXTENDS FROM 24N TO 31N BETWEEN 54W AND 69W...WITH A HIGHER CONCENTRATION OF THUNDERSTORM COVERAGE BETWEEN 54W AND 58W. FARTHER S...A 1012 MB LOW IS CENTERED NEAR 15N59W WITH A SURFACE TROUGH EXTENDING FROM 17N59W THROUGH THE LOW CENTER TO 13N60W. ISOLATED MODERATE CONVECTION IS FROM 15N TO 18N BETWEEN 57W AND 61W. OVER THE NEXT 24 HOURS CONVECTION WILL CONTINUE OVER THE W ATLC N OF 28 W OF 70W...AND NEAR THE UPPER LOW. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ LATTO