000 AXNT20 KNHC 071758 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT THU AUG 07 2014 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 1745 UTC. ...TROPICAL WAVES... TROPICAL WAVE IS OVER THE CENTRAL ATLC WITH AXIS EXTENDING FROM 19N33W TO 8N32W MOVING W AT 20 KT. METEOSAT PSEUDO NATURAL AND SAL TRACKING IMAGERY SHOW THE PRESENCE OF DUST AND DRY AIR IN THE WAVE ENVIRONMENT WHICH IS INHIBITING CONVECTION. TROPICAL WAVE IS JUST EAST OF THE LESSER ANTILLES WITH AXIS EXTENDING FROM 18N56W TO 9N58W MOVING W AT 20 KT. THE WAVE IS ASSOCIATED WITH DEEP LAYER MOISTURE WHICH ALONG UPPER LEVEL DIFFLUENCE SUPPORT SCATTERED MODERATE CONVECTION FROM 8N-15N BETWEEN 53W-63W. TROPICAL WAVE IS ON THE WESTERN CARIBBEAN WITH AXIS EXTENDING FROM 21N76W TO A 1011 MB LOW NEAR 9N76W...MOVING W AT 20 KT. AN UPPER-LEVEL INVERTED TROUGH SUPPORT THIS WAVE WHICH IS ENHANCING SCATTERED SHOWERS AND TSTMS FROM 14N-21N BETWEEN 72W-79W. SIMILAR CONVECTION IS S OF 12N BETWEEN 75W-82W. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE WEST COAST OF AFRICA NEAR 12N16W TO 10N25W TO 8N34W. THE ITCZ EXTENDS FROM 8N34W TO 8N46W TO 9N55W. SCATTERED MODERATE CONVECTION IS FROM 5N-9N E OF 16W...FROM 6N-11N BETWEEN 18W-30W AND FROM 4N-9N BETWEEN 37W- 47W. ...DISCUSSION... THE GULF OF MEXICO... A MIDDLE TO UPPER LEVEL ELONGATED ANTICYCLONE DOMINATES THE BASIN AND SUPPORT A SURFACE RIDGE ANCHORED BY A 1018 MB HIGH NEAR 26N88W WHICH IS PROVIDING VARIABLE LIGHT WINDS OF 5-10 KT. ANTICYCLONIC WIND ASSOCIATED WITH THIS HIGH IS ADVECTING LOW LEVEL MOISTURE INTO THE BASIN FROM THE CARIBBEAN AS WELL AS THE SW N ATLC WHICH IS FEEDING ISOLATED MODERATE CONVECTION AND TSTMS N OF 22N E OF 94W. OVER THE SW GULF...A MIDDLE-LEVEL INVERTED TROUGH SUPPORT A SURFACE TROUGH ALONG 23N98W TO 18N94W AS WELL AS SCATTERED MODERATE CONVECTION AND TSTMS S OF 24N W OF 94W. OTHERWISE...SURFACE RIDGING WILL PREVAIL ACROSS GREAT PORTIONS OF THE GULF DURING THE NEXT THREE DAYS. A TROPICAL WAVE IS FORECAST TO ENTER THE BAY OF CAMPECHE BY SUN MORNING. THE CARIBBEAN SEA... MODERATE LOW-LEVEL MOISTURE IS OVER THE CENTRAL AND SW CARIBBEAN ASSOCIATED WITH A TROPICAL WAVE MOVING ACROSS THIS REGION. AN UPPER- LEVEL LOW CENTERED OVER COASTAL WATERS OF NE CUBA IS SUPPORTING SCATTERED HEAVY SHOWERS AND TSTMS IN THE NORTHERN WAVE ENVIRONMENT TO INCLUDE EASTERN CUBA...JAMAICA...THE WINDWARD PASSAGE AND SW HAITI. UPPER-LEVEL DIFFLUENCE ENHANCE SCATTERED MODERATE CONVECTION ASSOCIATED WITH A 1011 MB LOW IN THE LOWER END OF THE WAVE. A SECOND TROPICAL WAVE WILL BE ENTERING THE EASTERN BASIN THIS EVENING. THIS WAVE IS ALREADY ENHANCING SCATTERED SHOWERS OVER THE WINDWARD ISLANDS. SEE THE TROPICAL WAVES SECTION FOR MORE DETAILS. OTHERWISE...BESIDES ISOLATED SHOWERS AND TSTMS NOTED OVER COASTAL WATERS OF SW CUBA...THE REMAINDER BASIN IS UNDER FAIR WEATHER CONDITIONS BEING SUPPORTED BY AN OVERALL DEEP LAYER DRY ENVIRONMENT. TRADES OF 20 KT ARE ACROSS THE CARIBBEAN EXCEPT FOR THE NW BASIN WHERE LIGHTER WINDS OF 5- 10 KT DOMINATE. THE WAVE TO ENTER THE BASIN LATER TODAY WILL BRING SHOWERS TO PUERTO RICO AND HISPANIOLA OVER THE WEEKEND. ...HISPANIOLA... SCATTERED HEAVY SHOWERS AND TSTMS ARE OVER SW HAITI AND THE WINDWARD PASSAGE BEING SUPPORTED BY THE PASSAGE OF A TROPICAL WAVE AND AN UPPER LEVEL LOW CENTERED OVER COASTAL WATERS OF NE CUBA. THE REST OF THE ISLAND IS UNDER FAIR WEATHER CONDITIONS BEING SUPPORTED BY DEEP LAYER DRY AIR. THESE CONDITIONS WILL PREVAIL THROUGH FRI MORNING. HOWEVER...THE WEEKEND TURNS GRAY AS THE PASSAGE OF A TROPICAL WAVE IS EXPECTED TO BRING HEAVY RAINFALL THROUGH SUNDAY. THE ATLANTIC OCEAN... A BROAD MIDDLE LEVEL TROUGH EXTENDING ACROSS THE EASTERN CONUS AND THE WESTERN ATLC CONTINUES TO SUPPORT A SURFACE TROUGH EXTENDING FROM 30N69W TO 27N75W TO 24N79W WHICH IS ENHANCING SCATTERED SHOWERS AND TSTMS WITHIN 60 NM OF ITS AXIS. FARTHER EAST OVER THE CENTRAL ATLC...A MIDDLE TO UPPER LEVEL LOW REFLECTS IS STILL ENHANCING ISOLATED SHOWERS FROM 25N-30N BETWEEN 51W-57W. OTHERWISE...A SURFACE RIDGE ANCHORED BY A 1027 MB HIGH NEAR 33N35W DOMINATES ELSEWHERE N OF 19N. FOR TROPICAL WAVES...SEE SECTION ABOVE. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ NR