000 AXNT20 KNHC 060004 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT FRI JUL 05 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 MOVING WEST NEAR 15 KT ACROSS THE EASTERN ATLC. ITS AXIS EXTENDS FROM 20N32W TO 09N31W AND BOTH THE TOTAL PRECIPITABLE WATER IMAGERY AS WELL AS THE METEOSAT-9 SAL TRACKING PRODUCT INDICATE THE WAVE IS EMBEDDED IN A VERY DRY ENVIRONMENT FROM THE LOWER TO THE MIDDLE LEVELS. THIS DRY AIR IS INHIBITING CONVECTION OR RAINSHOWERS IN THE VICINITY OF THE WAVE AXIS. A TROPICAL WAVE IS MOVING W-NW NEAR 5 KT...TOWARDS THE EASTERN CARIBBEAN. CURRENTLY ITS AXIS EXTENDS ALONG 18N46W TO 12N52W AND IS EMBEDDED MAINLY WITHIN A MODERATE MOIST ENVIRONMENT. THERE IS MINIMUM SAL DRY AIR INTERACTION WITH THIS WAVE AND SCATTERED RAINSHOWERS ARE FROM 15N-17N BETWEEN 49W-51W. A TROPICAL WAVE IS OVER THE FAR WESTERN CARIBBEAN MOVING W NEAR 10 KT. AS OF 2100 UTC THE AXIS OF THE WAVE IS ALONG 18N84W TO 09N81W AND EMBEDDED MAINLY IN A DRY ENVIRONMENT AT BOTH MIDDLE AND LOWER LEVELS. THERE IS NO CONVECTION ASSOCIATED WITH THIS WAVE AT THIS TIME. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE WEST AFRICAN COAST NEAR 17N16W TO 13N22W TO A 1011 MB LOW NEAR 07N27W TO 06N35W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 06N35W TO 06N43W 04N50W. WIDELY SCATTERED MODERATE CONVECTION IS FROM 06N- 11N E OF 18W. A CLUSTER OF SCATTERED MODERATE CONVECTION IS ASSOCIATED WITH THE AFOREMENTIONED LOW FROM 04N-08N BETWEEN 26W- 33W. ISOLATED MODERATE CONVECTION IS WITHIN 70 NM EITHER SIDE OF THE ITCZ AXIS W OF 40W. ...DISCUSSION... GULF OF MEXICO... SURFACE TROUGHING DOMINATES THE WESTERN GULF W OF 90W WHILE RETURN FLOW COVERS THE BASIN E OF THAT LONGITUDE. THE SURFACE TROUGH EXTENDS FROM 29N90W SW TO A 1011 MB LOW NEAR 22N96W. THESE SURFACE FEATURES ARE BEING SUPPORTED BY A NARROW UPPER LEVEL TROUGH THAT EXTENDS FROM THE GREAT LAKES TO THE GULF N OF 23N W OF 90W. ABUNDANT MOISTURE ACROSS THE BASIN AS WELL AS UPPER LEVEL DIFFLUENCE JUST EAST OF THE SURFACE TROUGH ARE ENHANCING NUMEROUS MODERATE/ISOLATED STRONG CONVECTION WITH EMBEDDED THUNDERSTORMS WITHIN 220 NM EAST OF THE AXIS. NUMEROUS MODERATE CONVECTION WITH ISOLATED THUNDERSTORMS EXTEND TO THE NE GULF N OF 25N. BY EARLY SUNDAY...THE SURFACE TROUGHING IS EXPECTED TO DISSIPATE AND RETURN FLOW WILL DOMINATE ACROSS THE BASIN. IN THE UPPER LEVELS...THE RIDGE THAT HAS BEEN CAUSING DIFFLUENCE WILL CONTINUE TO DRIFT W-NW WHICH COMBINED WITH ABUNDANT LOW LEVEL MOISTURE WILL SUSTAIN PRECIPITATION ACTIVITY ACROSS MOST OF THE BASIN. CARIBBEAN SEA... ABUNDANT LOWER LEVELS MOISTURE AND MIDDLE LEVEL DIFFLUENCE CONTINUE TO ENHANCE RAINSHOWERS AND ISOLATED THUNDERSTORMS OVER THE WESTERN CARIBBEAN N OF 17N W OF 75W...INCLUDING CUBA. PATCHES OF LOW LEVEL MOISTURE HAS BEEN ENHANCING RAINSHOWERS ACROSS THE LESSER ANTILLES WITHIN THE LAST COUPLE OF HOURS. THESE SHOWERS CAN EXTEND S OF 16N E OF 67W. A WEAK TROPICAL WAVE IS MOVING OFF THE WESTERN CARIBBEAN INTO CENTRAL AMERICA...AND CURRENTLY THERE IS NO CONVECTIVE ACTIVITY ASSOCIATED WITH IT. FOR THE MOST PART THE REST OF THE CARIBBEAN BASIN ENJOYS FAIR WEATHER SUPPORTED BY VERY 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. WEATHER CONDITIONS FOR THE WESTERN CARIBBEAN COULD IMPROVE EARLY ON SUNDAY WHILE NO MAJOR CHANGES ARE EXPECTED FOR THE REST OF THE BASIN. EARLY ON MONDAY A TROPICAL WAVE IS EXPECTED TO MOVE ACROSS THE EASTERN CARIBBEAN. HISPANIOLA... CURRENTLY MODERATE LOW LEVEL MOISTURE IS ACROSS THE ISLAND WHICH COMBINED WITH UPPER LEVEL DIFFLUENCE IS GENERATING A CLUSTER OF MODERATE/ISOLATED STRONG CONVECTION WITH EMBEDDED THUNDERSTORMS OVER HAITI. OVER THE REST OF THE ISLAND...ISOLATED SHOWERS AND TSTMS ARE POSSIBLE. EXCEPT FOR AFTERNOON SHOWERS DUE TO DAYTIME HEATING AND INSTABILITY...FAIR WEATHER MUST SET DURING SATURDAY AND SUNDAY. ATLANTIC OCEAN... BESIDES THE TROPICAL WAVES ALREADY MENTIONED ABOVE...BROAD SURFACE RIDGING COVERS THE ATLC WATERS ANCHORED BY A 1028 MB HIGH NEAR 34N70W AND ANOTHER HIGH NE OF THE AREA. 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 $$ NR