000 AXNT20 KNHC 101759 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT SAT AUG 10 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...TROPICAL WAVES... TROPICAL WAVE EXTENDS FROM 12N19W TO 21N18W MOVING W AT 10-15 KT. THE WAVE HAS EMERGED OFF THE COAST OF WEST AFRICA AND COINCIDES WITH A MID-LEVEL 700 MB TROUGH AXIS ALONG 19W. TOTAL PRECIPITABLE WATER IMAGERY INDICATES MAXIMUM VALUES FROM 08N-17N BETWEEN 13W-20W. SCATTERED MODERATE CONVECTION IS FROM 11N-15N BETWEEN 16W-23W. TROPICAL WAVE EXTENDS FROM 08N40W TO 20N42W MOVING W AT 15-20 KT. THE WAVE REMAINS ON THE LEADING EDGE OF SAHARAN DUST WHICH IS NOTED ON VISIBLE SATELLITE IMAGERY TO THE EAST OF THE WAVE AXIS. THIS SAHARAN AIR LAYER IS INHIBITING ANY DEEP CONVECTION AND RESULTING IN ONLY A FEW POSSIBLE SHOWERS ON THE NORTHERN EXTENT OF THE WAVE AXIS FROM 17N-25N BETWEEN 40W-45W. TROPICAL WAVE EXTENDS FROM 19N92W TO 26N88W MOVING W AT 10-15 KT. THE WAVE COINCIDES WITH A MIDDLE TO UPPER LEVEL LOW CENTERED OVER THE WESTERN GULF OF MEXICO NEAR 23N90W THAT IS PROVIDING A BROAD OVERALL CYCLONIC MOTION TO CLOUDS AND PRECIPITATION ACROSS THE GULF BASIN THIS AFTERNOON. WHILE IT IS DIFFICULT TO DIFFERENTIATE CONVECTION ASSOCIATED WITH THE UPPER LEVEL LOW AND THE TROPICAL WAVE AXIS...WIDELY SCATTERED MODERATE CONVECTION IS OCCURRING OVER THE SE GULF FROM 22N-28N BETWEEN 82W-91W. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 15N17W TO 11N22W TO 07N42W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 07N42W TO 06N47W TO 08N59W. ASIDE FROM CONVECTION ASSOCIATED WITH THE TROPICAL WAVE EMERGING OFF THE WEST AFRICA COAST ALONG 19W...SCATTERED MODERATE CONVECTION IS FROM 07N-11N BETWEEN 16W-20W...AND FROM 04N-09N BETWEEN 25W-29W. ISOLATED MODERATE CONVECTION IS FROM 07N-11N BETWEEN 55W-62W. ...DISCUSSION... GULF OF MEXICO... WATER VAPOR IMAGERY INDICATES A MIDDLE TO UPPER LEVEL LOW IS CENTERED OVER THE WESTERN GULF NEAR 23N90W THAT CONTINUES TO ADVECT MOISTURE OVER MUCH OF THE EASTERN AND CENTRAL GULF. MIDDLE TO UPPER LEVEL DIFFLUENCE ALONG WITH A TROPICAL WAVE ANALYZED ALONG 90W IS PRODUCING WIDELY SCATTERED SHOWERS AND ISOLATED TSTMS FROM 22N-28N BETWEEN 81W-92W. WHILE THE TROPICAL WAVE IS CERTAINLY IMPACTING CYCLONIC FLOW IN THE LOWER- LEVELS...IT APPEARS THE UPPER LEVEL LOW CONTINUES AS THE MORE DOMINATE FEATURE. TO THE WEST ALONG COASTAL SOUTHERN TEXAS AND COASTAL EASTERN MEXICO...A TROUGH OF LOW SURFACE PRESSURE IS ANCHORED BY A 1011 MB LOW CENTERED NEAR 23N96W. THE SURFACE TROUGH EXTENDING FROM THE TEXAS COAST NEAR 28N97W TO THE LOW CENTER THEN SE TO THE SOUTHERN MEXICO COAST NEAR 19N93W. WITH A SURFACE LOW IN PLACE AND THE MAXIMUM MIDDLE TO UPPER LEVEL DIFFLUENCE OVER THE SW GULF...SCATTERED SHOWERS AND TSTMS ARE OCCURRING WEST OF A LINE FROM THE TEXAS/LOUISIANA COAST NEAR 30N94W TO THE MEXICO COAST NEAR 19N92W. MOST OF THE CONVECTION IS OCCURRING OVER THE OFFSHORE WATERS...HOWEVER A FEW WIDELY SCATTERED SHOWERS AND ISOLATED TSTMS ARE OCCURRING INLAND OVER EAST-CENTRAL MEXICO FROM 19N-25N E OF 100W. THE SURFACE TROUGHING ACROSS THE WESTERN GULF IS EXPECTED TO VERY SLOWLY DRIFT WESTWARD AND WEAKEN OVER THE NEXT 24 TO 36 HOURS WITH PRIMARILY E-SE WINDS IN THE RANGE OF 10 TO 20 KT PREVAILING OVER THE GULF THROUGH EARLY TUESDAY. CARIBBEAN SEA... AN UPPER LEVEL ANTICYCLONIC CIRCULATION IS CENTERED OVER THE WESTERN CARIBBEAN NEAR 17N79W AND IS PROVIDING AN OVERALL DIFFLUENT ATMOSPHERE ALOFT W OF 70W. AT THE SURFACE...E-SE WINDS PREVAIL WITH AREAS OF LOW-LEVEL CONVERGENCE THAT CONTINUE TO GENERATE WIDELY SCATTERED SHOWERS AND ISOLATED TSTMS S OF 20N BETWEEN 70W-83W. ACROSS THE SW CARIBBEAN AND PORTIONS OF INLAND CENTRAL AMERICA...THE MOISTURE CONVERGENCE IS MARGINALLY STRONGER SPARKING SCATTERED SHOWERS AND TSTMS S OF 15N BETWEEN 80W-86W. FARTHER EAST...AN UPPER LEVEL LOW IS CENTERED NE OF THE LEEWARD ISLANDS NEAR 18N59W. PRIMARILY NW WINDS ALOFT DOMINATE E OF 70W WITH THE BASE OF THE TROUGH LOCATED OVER THE WINDWARD ISLANDS NEAR 12N61W. WHILE LOW-LEVEL MOISTURE CONVERGENCE IS GENERATING ISOLATED SHOWERS AND TSTMS BETWEEN 62W-70W...THE MIDDLE TO UPPER LEVEL DYNAMICS BECOME STRONGER E OF 62W AND ARE GENERATING SCATTERED SHOWERS AND TSTMS 11N-17N BETWEEN 53W-62W. MOST OF THE STRONGEST CONVECTION REMAINS DIRECTLY EAST OF SAINT LUCIA ALONG 14N AT THIS TIME. HISPANIOLA... CURRENTLY A FEW ISOLATED SHOWERS AND TSTMS ARE OCCURRING ACROSS THE ISLAND WITH THE MOST INTENSE AREAS OF THIS CONVECTION LOCATED WITHIN THE NORTHERN AND SOUTHERN ADJACENT COASTAL WATERS REGIONS. UPPER LEVEL WINDS ARE NORTHWESTERLY ALOFT AND WATER VAPOR IMAGERY INDICATES A FAIRLY DRY AIRMASS IN PLACE THAT IS EXPECTED TO STAY OVER THE REGION THE NEXT FEW DAYS. HOWEVER WITH E-SE WINDS PERSISTING ACROSS MUCH OF THE CARIBBEAN SEA AND SW NORTH ATLC WATERS THIS AFTERNOON AND EVENING...AND PEAK DAYTIME HEATING AND STABILITY TO OCCUR WITHIN THE NEXT FEW HOURS... SCATTERED SHOWERS AND TSTMS ARE POSSIBLE THROUGH LATE EVENING. ATLANTIC OCEAN... A MIDDLE TO UPPER LEVEL ANTICYCLONIC CIRCULATION IS CENTERED OVER A LARGE PORTION OF THE SW NORTH ATLC THAT CONTINUES TO SUPPORT A SURFACE RIDGE OF HIGH PRESSURE ANCHORED BY A 1022 MB HIGH CENTERED NEAR 31N69W. THE SURFACE RIDGE AXIS EXTENDS WESTWARD TO THE FLORIDA PENINSULA NEAR JACKSONVILLE AND E-NE TO BEYOND 33N60W. MOSTLY CLEAR SKIES AND FAIR CONDITIONS ACCOMPANY THIS FEATURE W OF 50W...HOWEVER A FEW ISOLATED SHOWERS AND TSTMS ARE OCCURRING IN THE VICINITY OF 28N66W. FARTHER EAST ACROSS THE CENTRAL AND EASTERN ATLC...FAIRLY BENIGN CONDITIONS ARE NOTED ON SATELLITE IMAGERY AS A SURFACE RIDGE DOMINATES. THE RIDGING IS ANCHORED BY A 1031 MB HIGH CENTERED NORTH OF THE AZORES NEAR 41N26W. ALSO OF NOTE...WHILE THE TROPICAL WAVES ARE DISCUSSED IN DETAIL ABOVE...BETWEEN THE WAVES A LARGE AREA OF SAHARAN DUST IS LOCATED GENERALLY N OF 10N E OF 40W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN