000 AXNT20 KNHC 121750 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT SUN JUL 12 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... TROPICAL WAVE EXTENDS FROM 10N31W TO 20N30W MOVING W AT 10 TO 15 KT OVER THE PAST 24 HOURS. THE WAVE COINCIDES WITH BROAD MID LEVEL TROUGHING NOTED BOTH ON SATELLITE IMAGERY AND IN THE 700 MB LEVELS ON THE GFS. THIS WAVE IS AT THE LEADING EDGE OF A POLEWARD SURGE IN MID LEVEL MOISTURE TO 16N. HOWEVER...SAHARAN DUST IS EVIDENT AS FAR S AS 15N ALONG THE WAVE AXIS. ISOLATED MODERATE CONVECTION IS FROM 05N TO 12N BETWEEN 28W AND 34W. TROPICAL WAVE EXTENDS FROM 09N52W TO 19N49W MOVING W AT AROUND 20 KT OVER THE PAST 24 HOURS. THE WAVE COINCIDES WITH A RELATIVELY BROAD 700 MB GLOBAL MODEL INDICATED TROUGH BETWEEN 48W AND 57W. THIS WAVE IS EMBEDDED IN RELATIVELY DRY AIR WITH SAHARAN DUST N OF 10N. HOWEVER...UPPER LEVEL DIFFLUENCE IS SUPPORTING ISOLATED MODERATE CONVECTION FROM 16N TO 19N BETWEEN 49W AND 53W. TROPICAL WAVE EXTENDS FROM 09N75W TO 19N74W MOVING W AT 15 TO 20 KT OVER THE PAST 24 HOURS. THE NORTHERN PORTION OF THIS WAVE IS MOVING UNDER AN UPPER LEVEL LOW WITH STRONG WESTERLY SHEAR OVER THE SOUTHERN PORTION OF THE WAVE. ALTHOUGH HIGH MOISTURE IS ALSO OVER THE SOUTHERN PORTION OF THE WAVE...THE PRESENCE OF THE SHEAR IS INHIBITING CONVECTION. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 12N16W TO 10N30W...WHERE THE ITCZ BEGINS AND CONTINUES THROUGH 08N40W TO THE S AMERICA COAST NEAR 06N58W. SCATTERED MODERATE CONVECTION IS FROM 04N TO 10N BETWEEN 12W AND 28W. ISOLATED MODERATE CONVECTION IS FROM 04N TO 11N BETWEEN 40W AND 57W. ...DISCUSSION... GULF OF MEXICO... MIDDLE TO UPPER LEVEL RIDGING CENTERED OVER TX CONTINUES TO PRODUCE NW WINDS ALOFT ACROSS THE MAJORITY OF THE GULF EXCEPT FOR THE SW BASIN. AT THE SURFACE...A CONVECTION FREE TROUGH IS OVER THE SW GULF FROM 22N92W TO 18N94W AND IS A DIURNAL EFFECT OF THE YUCATAN COAST PRODUCING WINDS TO 25 KT. A 1020 MB HIGH CENTERED NEAR 28N92W SUPPORTS LIGHT TO MODERATE ANTICYCLONIC FLOW ACROSS THE MAJORITY OF THE GULF BASIN. A SURFACE TROUGH EXTENDING FROM 31N83W TO 25N84W IS INTERACTING WITH A MOIST AIRMASS TO SUPPORT CLUSTERS OF MODERATE TO STRONG CONVECTION FROM 25N TO 29N BETWEEN 82W AND 88W...INCLUDING THE WEST-CENTRAL FL COAST. OVER THE NEXT 24 HOURS CONVECTION WILL CONTINUE TO BE POSSIBLE OVER THE EASTERN GULF IN THE VICINITY OF THE SURFACE TROUGH. CARIBBEAN SEA... AN UPPER LOW BETWEEN THE SE BAHAMAS AND CUBA IS PRODUCING CYCLONIC FLOW OVER THE MAJORITY OF THE CARIBBEAN BASIN. A REGION OF UPPER LEVEL DIFFLUENCE TO THE SOUTHEAST OF THE UPPER LOW IS SUPPORTING CLUSTERS OF MODERATE CONVECTION FROM 15N TO 20N BETWEEN 62W AND 70W...INCLUDING PUERTO RICO AND THE VIRGIN ISLANDS. MODERATE MOISTURE IN THE CYCLONIC FLOW SUPPORTS SCATTERED THUNDERSTORMS FROM 18N TO 22N BETWEEN 76W AND 88W...INCLUDING JAMAICA AND THE CAYMAN ISLANDS. UPPER LEVEL DIFFLUENCE OVER THE SW CARIBBEAN SUPPORTS CLUSTERS OF MODERATE TO STRONG CONVECTION S OF 13N W OF 79W. A TROPICAL WAVE IS OVER THE CENTRAL CARIBBEAN. PLEASE SEE THE TROPICAL WAVES SECTION FOR MORE DETAILS. TRADE WINDS ARE SLIGHTLY WEAKER TODAY THAN THE PREVIOUS SEVERAL DAYS OVER THE CARIBBEAN DUE TO THE WEAKENING OF SURFACE RIDGING OVER THE WESTERN ATLC. MODERATE TO FRESH TRADES COVER THE WESTERN AND EASTERN THIRDS OF THE BASIN...WITH FRESH TO STRONG TRADE WINDS OVER THE CENTRAL THIRD OF THE CARIBBEAN. THE UPPER LOW WILL LIFT NORTH AND WEST OVER THE NEXT 24 HOURS WHICH WILL TAKE THE FAVORABLE UPPER LEVEL DIFFLUENCE OUT OF THE BASIN...DECREASING CONVECTION OVER PUERTO RICO AND THE VIRGIN ISLANDS HEADING INTO MONDAY. A WESTWARD MOVING TROPICAL WAVE WILL HELP TO ENHANCE CONVECTION OVER THE WESTERN CARIBBEAN ON MONDAY. ...HISPANIOLA... A BROAD UPPER LOW CENTERED A COUPLE HUNDRED MILES NW OF THE ISLAND IS SUPPORTING UPPER LEVEL DIFFLUENCE WITH NUMEROUS SHOWERS MAINLY OVER THE EASTERN PORTION OF THE DOMINICAN REPUBLIC TODAY. THESE SHOWERS ARE FORECAST TO PERSIST INTO THE EVENING WHICH COULD RESULT IN HEAVY RAINFALL AND FLASH FLOODING WITH THE POTENTIAL FOR MUDSLIDES. SCATTERED THUNDERSTORMS ARE POSSIBLE OVER THE REMAINDER OF THE ISLAND THROUGH MONDAY. MODELS ARE FORECASTING THE HIGHEST CHANCES FOR HEAVY PRECIPITATION TO SHIFT NORTH OF THE ISLAND ON MONDAY. ATLANTIC OCEAN... A BROAD UPPER LOW IS CENTERED NEAR 22N74W AND SUPPORTS A LARGE AREA OF UNSETTLED WEATHER WITH NUMEROUS SHOWERS AND SCATTERED THUNDERSTORMS FROM 19N TO 26N BETWEEN 63W AND 77W. AN UPPER LEVEL RIDGE CENTERED NEAR 31N71W IS PRODUCING UPPER LEVEL DIFFLUENCE WHICH SUPPORTS WIDELY SCATTERED MODERATE CONVECTION FROM 28N TO 31N BETWEEN 51W AND 66W. A BROAD SURFACE RIDGE AXIS THROUGH A 1025 MB HIGH CENTERED NEAR 30N48W DOMINATES THE CENTRAL AND EASTERN SUBTROPICAL ATLC EAST OF 50W. TWO TROPICAL WAVES ARE OVER THE TROPICAL NORTHERN ATLC. PLEASE SEE THE TROPICAL WAVES SECTION FOR MORE DETAILS. OVER THE NEXT 24 HOURS EXPECT CONVECTION TO CONTINUE ACROSS THE SOUTHWESTERN NORTHERN ATLC NEAR THE UPPER LOW. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ LATTO