000 AXNT20 KNHC 202349 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT SUN JUN 20 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2300 UTC... ...TROPICAL WAVES... TROPICAL WAVE HAS PUSHED OFF THE COAST OF AFRICA ALONG 18W S OF 13N MOVING W 10-15 KT. A DRY LOW-LEVEL VORTICITY CENTER IS AHEAD OF THE WAVE CENTERED BY A 1009 MB LOW NEAR 14N21W. UPPER-AIR TIME SECTION ANALYSIS FROM DAKAR SENEGAL INDICATES THIS LOW CENTER PASSING AROUND 06/20 0000 UTC. TOTAL PRECIPITABLE WATER IMAGERY ALSO INDICATES A DRY CIRCULATION ABOUT THE LOW CENTER WITH A PEAK IN DEEP LAYER MOISTURE TO THE E ALONG THE WAVE AXIS. SCATTERED MODERATE/STRONG CONVECTION IS FROM 4N-10N BETWEEN 16W-23W. ISOLATED MODERATE/STRONG CONVECTION IS FROM 4N-8N BETWEEN 23W-28W. TROPICAL WAVE EXTENDS ALONG 10N44W TO 5N46W MOVING W 10-15 KT. LAST VISIBLE SATELLITE IMAGES OF THE DAY INDICATE CYCLONIC FLOW ABOUT THE WAVE AXIS. THE WAVE ALSO LIES EMBEDDED IN A MAXIMUM IN DEEP LAYER MOISTURE SEEN IN TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED MODERATE/STRONG CONVECTION IS FROM 7N-10N BETWEEN 42W-47W. TROPICAL WAVE IS W OF THE LESSER ANTILLES ALONG 62W/63W S OF 15N MOVING W NEAR 15 KT. THE WAVE COINCIDES WITH A DEEP LAYER MOISTURE MAXIMUM EVIDENT IN TOTAL PRECIPITABLE WATER IMAGERY. BROAD CYCLONIC FLOW IS IN THE VICINITY OF THE WAVE INDICATED BY SATELLITE IMAGERY. NUMEROUS STRONG CONVECTION IS INLAND OVER VENEZUELA FROM 5N-10N BETWEEN 61W-64W. NUMEROUS MODERATE/SCATTERED STRONG CONVECTION IS FROM 11N-15N BETWEEN 59W-65W AFFECTING A LARGE PORTION OF THE LESSER ANTILLES. TROPICAL WAVE EXTENDS ALONG 22N73W TO 11N75W MOVING W NEAR 15 KT. THE WAVE LIES W OF A LARGE AREA OF DEEP LAYER MOISTURE EVIDENT IN TOTAL PRECIPITABLE WATER IMAGERY. VISIBLE SATELLITE IMAGERY INDICATES A SHARP SE-NE WIND SHIFT ABOUT THE WAVE AXIS. SCATTERED MODERATE/STRONG CONVECTION IS FROM 18N-20N BETWEEN 69W-75W ACROSS MUCH OF HISPANIOLA. SIMILAR ACTIVITY IS ACROSS ERN CUBA FROM 19N-21N BETWEEN 75W-78W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 14N-18N BETWEEN 68W-75W. ...ITCZ... ITCZ AXIS IS CENTERED ALONG 6N10W 8N19W 4N30W 6N41W 7N52W 9N61W. AN EMBEDDED SURFACE TROUGH IS ALONG 38W S OF 10N. SCATTERED MODERATE/STRONG CONVECTION IS W OF THE TROUGH FROM 4N-9N BETWEEN 39W-43W. SIMILAR ACTIVITY IS WITHIN 150 NM N...90 NM S OF THE AXIS BETWEEN 47W-61W. ...DISCUSSION... GULF OF MEXICO... A SHORTWAVE UPPER LEVEL TROUGH EXTENDING ACROSS THE SE UNITED STATES SUPPORTS A SURFACE TROUGH EXTENDING FROM A 1015 MB LOW OVER SRN GEORGIA NEAR 31N83W ACROSS THE BIG BEND OF FLORIDA INTO THE CENTRAL GULF NEAR 27N89W. ISOLATED SHOWERS/THUNDERSTORMS ARE ACROSS MUCH OF THE NRN HALF OF THE BASIN N OF 24N BECOMING MORE CONCENTRATED NEAR THE TROUGH AXIS OVER LAND. DAYTIME HEATING AND SEABREEZE CONVERGENCE OVER THE FLORIDA PENINSULA IS ALSO ENHANCING SCATTERED SHOWERS/THUNDERSTORMS ACROSS MUCH OF THE FLORIDA PENINSULA. ELSEWHERE...A WEAK PRESSURE GRADIENT IS ACROSS THE BASIN CONTRIBUTING TO LIGHT E-SE WINDS. ALOFT...AN UPPER LEVEL RIDGE CENTERED OVER SRN TEXAS IS PROVIDING MAINLY N-NE FLOW. EXPECT LITTLE CHANGE OVER THE NEXT 24 HRS. CARIBBEAN SEA... ISOLATED SHOWERS/THUNDERSTORMS HAVE FLARED UP OVER CUBA DUE TO DAYTIME HEATING AND SEABREEZE CONVERGENCE. A TROPICAL WAVE IN THE E PACIFIC ALONG 89W IS ENHANCING A LARGE AREA OF SHOWERS/THUNDERSTORMS ACROSS CENTRAL AMERICA. SCATTERED MODERATE/STRONG CONVECTION IS FROM 10N-14N W OF 81W AFFECTING COSTA RICA...AND NICARAGUA. ISOLATED SHOWERS/THUNDERSTORMS ARE ALSO ACROSS THE SW CARIBBEAN S OF 11N DUE TO SURFACE CONVERGENCE NEAR THE E PACIFIC ITCZ WHICH CROSSES OVER COSTA RICA TO THE COAST OF PANAMA. A SECOND TROPICAL WAVE EXTENDING ACROSS THE WINDWARD PASSAGE FROM 22N73W TO 11N75W IS SUPPORTING A LARGE AREA OF SHOWERS/THUNDERSTORMS ACROSS THE NRN CARIBBEAN IMPACTING ERN CUBA AND HISPANIOLA. SEE TROPICAL WAVE SECTION ABOVE FOR MORE DETAILS. A SURFACE TROUGH ACROSS VENEZUELA ALONG 69W S OF 13N IS ENHANCING SCATTERED SHOWERS/THUNDERSTORMS ACROSS MUCH OF NRN VENEZUELA...COLOMBIA AND INTO THE CARIBBEAN S OF 14N. A THIRD TROPICAL WAVE ALONG 62W/63W IS SUPPORTING SHOWERS/THUNDERSTORMS AFFECTING NE VENEZUELA AND THE LESSER ANTILLES. SEE TROPICAL WAVE SECTION FOR MORE DETAILS. ISOLATED SHOWERS/POSSIBLE THUNDERSTORMS ARE ALSO ACROSS THE FAR NE CARIBBEAN AFFECTING PUERTO RICO AND THE LEEWARD ISLANDS. THIS ACTIVITY ALONG WITH ALL THE ACTIVITY ACROSS THE ERN HALF OF THE BASIN DUE TO TROPICAL WAVES ARE FURTHER ENHANCED BY A DIFFLUENT ZONE ALOFT BETWEEN AN UPPER LEVEL TROUGH COVERING THE WRN HALF OF THE AREA CENTERED N OF CUBA NEAR 23N79W...AND AN UPPER LEVEL RIDGE COVERING THE ERN PORTION CENTERED E OF THE LESSER ANTILLES NEAR 13N57W. DRY AIR IS FLOWING AROUND THE UPPER LEVEL TROUGH KEEPING THE REMAINDER OF THE WRN CARIBBEAN UNDER FAIR CONDITIONS. EXPECT CONTINUED SHOWER ACTIVITY ACROSS MUCH OF THE BASIN AS THE TROPICAL WAVES MOVE WWD. ATLANTIC OCEAN... SCATTERED SHOWERS/THUNDERSTORMS ARE ACROSS MUCH OF THE FLORIDA PENINSULA AND THE NW BAHAMAS ENHANCED BY DAYTIME HEATING AND SEABREEZE CONVERGENCE. AN UPPER LEVEL TROUGH CENTERED N OF CUBA NEAR 23N79W IS ENHANCING A LARGE AREA OF SHOWER ACTIVITY ACROSS THE NRN CARIBBEAN. ISOLATED SHOWERS/THUNDERSTORMS CONTINUE INTO THE SW N ATLC TO 22N BETWEEN 61W-73W. THE REMAINDER OF THE W ATLC IS INFLUENCED BY DRY AIR ALOFT...AND WEAK SURFACE RIDGING FROM THE NE KEEPING CONDITIONS FAIR. FARTHER E...SURFACE RIDGING DOMINATES ANCHORED BY A 1028 MB NEAR 33N33W...AND A 1027 MB HIGH NEAR 34N27W PROVIDING GENERALLY FAIR WEATHER ACROSS THE ERN ATLC. A 1009 MB LOW IS CENTERED OFF THE AFRICAN COAST NEAR 14N21W. THIS CIRCULATION IS ASSOCIATED WITH THE TROPICAL WAVE ALONG 18W. A DRY SAHARAN AIR LAYER WRAPS AROUND THE LOW CIRCULATION ACCOMPANIED BY AFRICAN DUST EXTENDING TO 32W S OF 25N EVIDENT IN THE LAST VISIBLE SATELLITE IMAGES OF THE DAY. ALOFT...AN UPPER LEVEL TROUGH EXTENDS FROM NEAR 31N28W TO 13N46W EMBEDDED BETWEEN TWO UPPER LEVEL RIDGES CENTERED NEAR 13N57W AND 13N31W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ WALTON