000 AXNT20 KNHC 191750 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT THU AUG 19 2010 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...METEOROLOGICAL ANALYSIS...WEATHER OBSERVATIONS...AND RADAR. BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1630 UTC. ...TROPICAL WAVES... TROPICAL WAVE IS EXTENDING FROM 24N33W TO 11N33W MOVING W NEAR 15 KT. LOW-LEVEL CYCLONIC FLOW IS ABOUT THE WAVE AXIS EVIDENT IN VISIBLE SATELLITE IMAGERY AND CONFIRMED BY AN ASCAT SCATTEROMETER PASS. THIS WAVE ALSO COINCIDES WITH A MAXIMUM IN DEEP LAYER MOISTURE INDICATED BY TOTAL PRECIPITABLE WATER IMAGERY. CONVECTION IS LIMITED TO THE ITCZ. TROPICAL WAVE IS IN THE CENTRAL ATLC EXTENDING FROM 25N41W TO 10N40W MOVING W NEAR 10 KT. A LARGE SURGE OF DEEP LAYER MOISTURE IS E OF THE WAVE AXIS...WHILE SIGNIFICANT DRY AIR IS WRAPPING AROUND THE WRN SIDE SUPPRESSING ANY CONVECTION NEAR THE WAVE. TROPICAL WAVE IS MOVING ACROSS THE WRN CARIBBEAN FROM WRN CUBA NEAR 24N83W TO PANAMA NEAR 9N82W MOVING W NEAR 15 KT. VISIBLE SATELLITE IMAGERY INDICATES CYCLONIC FLOW IS ABOUT THE WAVE AXIS. THE WAVE ALSO COINCIDES WITH AN AREA OF ENHANCED MOISTURE ACROSS THE WRN CARIBBEAN EVIDENT IN TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED MODERATE/STRONG CONVECTION IS WITHIN 130 NM W...240 NM E OF THE AXIS S OF 22N. AN UPPER LEVEL TROUGH ACROSS THE YUCATAN PENINSULA IS ENHANCING CONVECTION ALONG THE WAVE. ...THE ITCZ... ITCZ AXIS IS CENTERED FROM GUINEA NEAR 11N15W ALONG 8N23W 11N33W 9N48W 12N54W. SCATTERED MODERATE/STRONG CONVECTION FROM 10N-14N BETWEEN 16W AND 29W ENHANCED BY A MONSOON TROUGH EXTENDING FROM INLAND AFRICA NEAR 20N7W TO 13N27W. SCATTERED MODERATE CONVECTION IS FROM 3N-10N BETWEEN 13W-36W. ...DISCUSSION... THE GULF OF MEXICO... SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE ACROSS THE NRN GULF N OF 27N W OF 82W. THIS ACTIVITY IS ENHANCED BY A SHORTWAVE UPPER LEVEL TROUGH ACROSS THE SOUTHEAST CONUS. TOTAL PRECIPITABLE WATER IMAGERY INDICATES ENHANCED MOISTURE ACROSS MUCH OF THE NRN GULF NEAR THIS SHOWER ACTIVITY. A WEAK SURFACE TROUGH PARALLELS THE MEXICAN COAST FROM NEAR 22N97W TO 19N94W. ISOLATED SHOWERS/THUNDERSTORMS ARE WITHIN 60 NM OF THE AXIS. THE REMAINDER OF THE BASIN IS EXPERIENCING GENERALLY FAIR WEATHER UNDER THE INFLUENCE OF SURFACE RIDGING EXTENDING FROM THE W ATLANTIC. ALOFT MAINLY NE FLOW COVERS THE BASIN AROUND AN UPPER LEVEL RIDGE CENTERED OVER WRN TEXAS. AN UPPER LEVEL TROUGH COVERS THE SRN GULF WITH THE AXIS ACROSS THE YUCATAN PENINSULA. EXPECT SURFACE RIDGING TO CONTINUE BUILDING WWD ACROSS THE GULF OVER THE NEXT SEVERAL DAYS. THE CARIBBEAN SEA... A TROPICAL WAVE EXTENDING FROM WRN CUBA TO PANAMA IS IMPACTING MUCH OF THE WRN CARIBBEAN. SCATTERED SHOWERS/THUNDERSTORMS COVER THE AREA W OF 79W. AN UPPER LEVEL TROUGH IS ACROSS THE YUCATAN PENINSULA PROVIDING DIFFLUENCE ALOFT NEAR THE WAVE AXIS FURTHER SUPPORTING CONVECTION. SEE TROPICAL WAVE SECTION FOR MORE DETAILS. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE ALSO ACROSS THE SW CARIBBEAN DUE TO SURFACE CONVERGENCE NEAR A PORTION OF THE ITCZ EXTENDING ALONG 11N TO NRN COLOMBIA. THE REMAINDER OF THE BASIN IS EXPERIENCING GENERALLY FAIR WEATHER UNDER THE INFLUENCE OF DRY AIR ALOFT ALONG WITH AN AREA OF AFRICAN DUST INDICATED BY SATELLITE IMAGERY AND SURFACE OBSERVATIONS ACROSS MUCH OF THE ERN HALF OF THE BASIN. A FEW SHOWERS/THUNDERSTORMS ARE BEGINNING TO IMPACT THE LEEWARD ISLANDS ASSOCIATED WITH AN UPPER LEVEL LOW NEAR 20N61W. EXPECT CONTINUED SHOWER ACTIVITY ACROSS THE WRN CARIBBEAN AS THE TROPICAL WAVE MOVES WWD. THE ATLANTIC OCEAN... SURFACE RIDGING COVERS THE W ATLC AROUND A 1018 MB HIGH NEAR 27N69W PROVIDING MOSTLY FAIR CONDITIONS ACROSS THE AREA SUPPORTED BY AN UPPER LEVEL RIDGE CENTERED NEAR 33N67W. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE LOCATED ALONG 62W FROM 17N-27N ASSOCIATED WITH AN UPPER LEVEL LOW NEAR 20N61W. A SURFACE TROUGH E OF THE LESSER ANTILLES EXTENDS FROM 24N55W TO 10N56W SUPPORTING ISOLATED SHOWERS WITHIN 120 NM OF THE AXIS. A SURFACE TROUGH IS S OF THE FRONT ALONG 30N53W TO 26N57W SUPPORTING ISOLATED SHOWERS/THUNDERSTORMS WITHIN 100 NM OF THE AXIS. AN UPPER LEVEL TROUGH NEAR 20N61W SUPPORTS THE SURFACE TROUGH. A MONSOON TROUGH EXTENDING OFF THE COAST OF AFRICA NEAR 20N7W TO 13N27W ENHANCING CONVECTION TO THE S NEAR THE AXIS OF THE ITCZ. TO THE NE...SURFACE RIDING DOMINATES ANCHORED BY A PAIR OF 1021 MB HIGHS TO EITHER SIDE OF THE AZORES ISLANDS HIGH NEAR 33N34W AND 36N19W MAINTAINING FAIR WEATHER. ALOFT...AN UPPER LEVEL RIDGE IS COVERING THE E ATLC CENTERED NEAR 25N34W. AN UPPER LEVEL TROUGH EXTENDS FROM THE CANARY ISLANDS NEAR 28N16W TO THE CAPE VERDE ISLANDS NEAR 18N24W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ WALTON/HOLLEY