000 AXNT20 KNHC 050004 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT THU JUL 04 2013 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... A TROPICAL WAVE IS OVER THE EASTERN ATLC EXTENDING FROM 23N26W TO 14N27W...MOVING W-NW NEAR 5 KT. TOTAL PRECIPITABLE WATER IMAGERY INDICATE THIS WAVE CONTINUES EMBEDDED IN A LOW TO MODERATE MOIST ENVIRONMENT AT THE LOWER LEVELS. IN ADDITION...THE METEOSAT-9 SAL TRACKING PRODUCT CONFIRMS THIS WAVE IS EMBEDDED WITHIN THE SAL DRY AIR WHICH IS HINDERING CONVECTION. A TROPICAL WAVE IS WEST OF THE ITCZ EXTENDING FROM 15N42W TO 06N51W...MOVING W-NW NEAR 5 KT. TOTAL PRECIPITABLE WATER IMAGERY SHOW THE WAVE IS EMBEDDED IN A MOSTLY HIGH MOIST ENVIRONMENT AT THE LOWER LEVELS. THE METEOSAT-9 SAL TRACKING PRODUCT SHOW THE WAVE IS BEING ENGULFED BY SAL DRY AIR...HOWEVER THIS DRY AIR IS GREATER THAN 220 NM FAR AWAY FROM THE AXIS WHICH IS PERMITING THE DEVELOPMENT OF SOME CONVECTION. SCATTERED MODERATE CONVECTION COINCIDES WITH A MAXIMUM IN TOTAL PRECIPITABLE WATER IMAGERY FROM 10N-14N BETWEEN 47W-50W. ISOLATED SHOWERS AND THUNDERSTORMS ARE WITHIN 40 NM EITHER SIDE OF THE REMAINDER WAVE AXIS. A TROPICAL WAVE IS OVER THE CENTRAL CARIBBEAN EXTENDING FROM 20N71W TO 10N73W...MOVING W-NW NEAR 10 KT. THERE IS LOW TO MODERATE MOISTURE AT THE LOWER LEVELS WITHIN THE WAVE ENVIRONMENT. HOWEVER UPPER LEVEL DIFFLUENCE FROM AN ELONGATED CYCLONIC CIRCULATION EXTENDING FROM THE COASTLINE OF SOUTH CAROLINA TO EASTERN CUBA AND A BROAD RIDGE EXTENDING FROM THE GULF TO WEST OF 73W IS ENHANCING A CLUSTER OF MODERATE/ISOLATED STRONG CONVECTION WITH EMBEDDED THUNDERSTORMS OVER HAITI. SCATTERED MODERATE CONVECTION IS OCCURRING ACROSS DOMINICAN REPUBLIC. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE WEST AFRICAN COAST NEAR 10N14W TO 08N20W TO 08N30W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 08N30W TO 07N37W TO 09N43W. SCATTERED MODERATE CONVECTION AND ISOLATED THUNDERSTORMS ARE FROM 04N-10N BETWEEN 17W-24W. SCATTERED MODERATE CONVECTION IS FROM 04N-09N E OF 16W AND FROM 01N-03N BETWEEN 25W-31W. ...DISCUSSION... GULF OF MEXICO... SOUTHERLY FLOW ACROSS THE EASTERN GULF CONTINUES TO ADVECT MOIST AIR INLAND...INCLUDING ALABAMA...GEORGIA AND THE FLORIDA PENINSULA. THE MOIST AIR AND UPPER LEVEL DIFFLUENCE FROM A RIDGE EXTENDING FROM SOUTH CAROLINA SW TO THE BAY OF CAMPECHE AND THE UPPER LEVEL TROUGH CENTERED OVER THE CENTRAL U.S. THAT DIPS INTO THE GULF N OF 28N W OF 87W CONTINUE TO ENHANCE SCATTERED MODERATE CONVECTION AND ISOLATED THUNDERSTORMS E OF 90W. OVER THE REMAINDER GULF SURFACE TROUGHING DOMINATES. THE FIRST TROUGH EXTENDS FROM 30N88W SW TO 27N92W 26N96W BEING SUPPORTED BY THE UPPER LEVEL TROUGH. SCATTERED SHOWERS ARE OCCURRING WITHIN 80 NM WEST OF THIS AXIS. THE SECOND SURFACE TROUGH IS ON THE BAY OF CAMPECHE WITH AXIS EXTENDING FROM 24N93W TO A 1010 MB LOW NEAR 20N93W TO 18N93W. A VERY MOIST ENVIRONMENT AT THE LOWER LEVELS AS WELL AS UPPER LEVEL DIVERGENCE ARE ENHANCING SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS S OF 25N BETWEEN THE AXIS AND THE YUCATAN PENINSULA. WITHIN THE NEXT 48 HOURS...BOTH SURFACE AND UPPER LEVEL RIDGING WILL DOMINATE ACROSS THE GULF. SE-SLY FLOW WILL CONTINUE TO ADVECT MOIST AIR ACROSS THE NORTHERN GULF AND SHOWERS/THUNDERSTORMS ARE EXPECTED TO CONTINUE WITHIN THAT PERIOD OR UNTIL SATURDAY EVENING. CARIBBEAN SEA... A TROPICAL WAVE IS OVER THE CENTRAL CARIBBEAN EXTENDING FROM 20N71W TO 10N73W. THERE IS LOW TO MODERATE MOISTURE AT THE LOWER LEVELS WITHIN THE WAVE ENVIRONMENT. HOWEVER UPPER LEVEL DIFFLUENCE FROM AN ELONGATED CYCLONIC CIRCULATION EXTENDING FROM THE COASTLINE OF SOUTH CAROLINA TO EASTERN CUBA AND A BROAD RIDGE EXTENDING FROM THE GULF TO WEST OF 73W IS ENHANCING A CLUSTER OF MODERATE/ISOLATED STRONG CONVECTION WITH EMBEDDED THUNDERSTORMS OVER HAITI. SCATTERED MODERATE CONVECTION IS OCCURRING ACROSS DOMINICAN REPUBLIC. SCATTERED MODERATE CONVECTION AND THUNDERSTORMS ASSOCIATED WITH THE WAVE AND UPPER LEVEL DIFFLUENCE EXTENDS ACROSS EASTERN CUBA. SIMILAR CONVECTION EXTENDS ACROSS THE REST OF CUBA AS WELL AS N OF 16N BETWEEN 78W- 85W ENHANCED BY A MOIST AT THE LOWER LEVELS AND DIFFLUENCE AT THE MIDDLE LEVELS. IN THE REMAINDER OF THE CARIBBEAN FAIR WEATHER DOMINATES SUPPORTED BY THE PRESENCE OF DRY AIR AT THE LOWER AND MIDDLE LEVELS. OTHERWISE...TRADEWINDS IN THE RANGE OF 15-20 KT SPREAD ACROSS THE BASIN WITH THE STRONGEST WINDS BEING ON THE CENTRAL CARIBBEAN. THE TROPICAL WAVE IS EXPECTED TO WEAKEN WHILE MOVING ACROSS CUBA DURING FRIDAY. SCATTERED SHOWERS WILL ACCOMPANY THIS WAVE BEING SUPPORTED BY A PREVAILING UPPER LEVEL PATTERN DRIFTING WESTWARD. HISPANIOLA... A TROPICAL WAVE AXIS IS MOVING ACROSS HAITI. THERE IS LOW TO MODERATE MOISTURE AT THE LOWER LEVELS WITHIN THE WAVE ENVIRONMENT. HOWEVER UPPER LEVEL DIFFLUENCE FROM AN ELONGATED CYCLONIC CIRCULATION EXTENDING FROM THE COASTLINE OF SOUTH CAROLINA TO EASTERN CUBA AND A BROAD RIDGE EXTENDING FROM THE GULF TO WEST OF 73W IS ENHANCING A CLUSTER OF MODERATE/ISOLATED STRONG CONVECTION WITH EMBEDDED THUNDERSTORMS OVER HAITI. SCATTERED MODERATE CONVECTION IS OCCURRING ACROSS DOMINICAN REPUBLIC. RAINSHOWERS ARE EXPECTED TO CONTINUE ACROSS THE ISLAND WITHIN THE NEXT 48 HOURS BEING MOSTLY ENHANCED BY A CONTINUAL UPPER LEVEL DIFFLUENT PATTERN AND MODERATE MOISTURE AT THE LOWER LEVELS. ATLANTIC OCEAN... BESIDES THE TROPICAL WAVES ALREADY MENTIONED ABOVE...BROAD SURFACE RIDGING COVERS THE ATLC WATERS ANCHORED BY A 1029 MB HIGH NEAR 34N67W AND THE 1027 MB AZORES HIGH NEAR 38N24W. THE TAIL OF A COLD FRONT EXTENDS FROM 30N49W TO 28N54W. SCATTERED SHOWERS ARE FROM 23N-28N BETWEEN 55W-60W AS WELL AS N OF CUBA AND THE BAHAMAS FROM 20N-24N BETWEEN 73W-78W. OTHERWISE...TOTAL PRECIPITABLE WATER IMAGERY SHOW VERY DRY AIR ACROSS THE REMAINDER REGION AT THE LOWER LEVELS WHICH IS ASSISTING IN SUPPRESSING CONVECTIVE ACTIVITY. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ RAMOS