000 AXNT20 KNHC 301746 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT THU MAY 30 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. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE COAST OF SENEGAL NEAR 13N17W TO 9N21W. THE ITCZ BEGINS NEAR 9N21W AND CONTINUES ALONG 7N34W 4N46W 5N53W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 4N-8N BETWEEN 30W-46W. SIMILAR ACTIVITY IS FROM 6N-11N BETWEEN 52W-60W. ...DISCUSSION... GULF OF MEXICO... SE RETURN FLOW OF 15-20 KT SPREADS ACROSS THE GULF OF MEXICO AROUND BROAD SURFACE RIDGING DOMINATING THE EASTERN CONUS. UPPER LEVEL RIDGING ALONG 86W SUPPORTS THE SURFACE RIDGE. UPPER LEVEL TROUGHING IS TO EITHER SIDE. THE UPPER TROUGH TO THE WEST ALONG THE EASTERN MEXICO COAST IS ONLY SUPPORTING A FEW UPPER LEVEL CLOUDS ACROSS THE BASIN. HOWEVER...THE UPPER TROUGH TO THE EAST NEAR 79W IS PROVIDING DIFFLUENT FLOW ALOFT ACROSS THE SW NORTH ATLC AND COMBINING WITH THE EFFECTS OF LOW LEVEL TROPICAL MOISTURE STREAMING FROM THE SOUTHEAST. THIS LOW-LEVEL MOISTURE CONTINUES OVER MUCH OF THE FLORIDA PENINSULA SUPPORTING SCATTERED SHOWERS SOUTH OF 29N. IN THE SW GULF...THE EAST PACIFIC SYSTEM T.D. BARBARA IS JUST ALONG THE MEXICO COAST NEAR 18.5N 95.0W. ONLY A FEW ISOLATED SHOWERS ARE OVER GULF WATERS FROM 18N-20N BETWEEN 92W-96W. THE SYSTEM IS EXPECTED TO MOVE NW ALONG THE COASTLINE AND MAY CONTINUE TO PRODUCE SHOWERS/THUNDERSTORMS IN THE SW GULF. CARIBBEAN SEA... ABUNDANT DEEP LAYER MOISTURE IS THROUGHOUT THE WESTERN CARIBBEAN EVIDENT IN TOTAL PRECIPITABLE WATER IMAGERY. THIS IS DUE TO BOTH LOW-LEVEL MOISTURE CONVERGENCE AND UPPER LEVEL DIFFLUENT FLOW AROUND THE BASE OF AN UPPER TROUGH OVER CENTRAL CUBA...AND AROUND AN UPPER RIDGE OVER CENTRAL AMERICA. THE COMBINATION IS SUPPORTING A LARGE CLUSTER OF STRONG SHOWERS AND SCATTERED THUNDERSTORMS FROM 11N-15N BETWEEN 76W-80W...AND SCATTERED SHOWERS/ISOLATED THUNDERSTORMS FROM 12N-20N BETWEEN 80W-85W. A WEAK 1010 MB SURFACE LOW IS ALSO ANALYZED OFF THE COAST OF NICARAGUA NEAR 12N83W NEAR THE END OF THE MONSOON TROUGH THAT EXTENDS FROM THE EPAC THROUGH COSTA RICA TO THE LOW. ISOLATED SHOWERS ARE MOVING THROUGH PORTIONS OF THE EASTERN AND CENTRAL CARIBBEAN EMBEDDED WITHIN TRADEWIND FLOW OF 20 KT. THE UPPER TROUGH OVER CENTRAL CUBA IS ALSO SUPPORTING SHOWERS AND THUNDERSTORMS OVER EASTERN CUBA...JAMAICA...AND HISPANIOLA. LITTLE CHANGE IS EXPECTED WITH DEEP MOISTURE REMAINING OVER MUCH OF THE CENTRAL AND WESTERN CARIBBEAN. HISPANIOLA... AN UPPER LEVEL TROUGH NEAR 78W CONTINUES TO PROVIDE MOIST AND DIFFLUENT FLOW ALOFT OVER HISPANIOLA. CURRENTLY...SCATTERED LOW- LEVEL SHOWERS ARE PRESENT. AS THE DAY CONTINUES...DEEP CONVECTION IS MORE LIKELY TO FORM DUE TO DAYTIME HEATING. THIS PATTERN IS EXPECTED TO CONTINUE AS THE UPPER TROUGH DRIFTS EAST AND WILL CONTINUE TO PROVIDE A FAVORABLE UPPER LEVEL ENVIRONMENT FOR CONVECTIVE ACTIVITY...ESPECIALLY IN THE AFTERNOON AND EVENING HOURS. ATLANTIC OCEAN... AN UPPER LEVEL TROUGH NEAR 77W/78W CONTINUES TO PROVIDE A LARGE AREA OF DIFFLUENCE ALOFT ACROSS THE WEST ATLC SUPPORTING WIDESPREAD SHOWERS/THUNDERSTORMS FROM 21N-29N BETWEEN 70W-76W. SCATTERED SHOWERS/POSSIBLE THUNDERSTORMS CONTINUE WESTWARD FROM 24N-28N WEST OF 76W AND OVER THE FLORIDA PENINSULA. AN UPPER LEVEL RIDGE TO THE EAST ALONG 69W SUPPORTS BROAD SURFACE RIDGING ACROSS THE WEST ATLC EXTENDING FROM A 1031 MB HIGH CENTERED TO THE NORTH NEAR 38N56W. A COUPLE OF WEAK SURFACE TROUGHS PROVIDE A WEAKNESS IN THE RIDGE. THE FIRST IS ALONG 32N50W TO 27N56W. THE SECOND IS ALONG 30N46W 26N46W. ISOLATED SHOWERS ARE WITHIN 60 NM EAST OF BOTH AXIS. THE TROUGHS ARE SUPPORTED BY AN UPPER LEVEL TROUGH EXTENDING ALONG 44N44W 26N50W 15N61W. THE REMAINDER OF THE EAST ATLC IS DOMINATED BY SURFACE RIDGING AROUND A 1035 MB HIGH NEAR 41N27W. VISIBLE SATELLITE IMAGERY INDICATES AN AREA OF DUST EXTENDS FROM THE COAST OF AFRICA TO NEAR 60W SOUTH OF 22N. ALOFT...BROAD UPPER LEVEL RIDGING COVERS THE EASTERN ATLC NEAR 35N25W...AS WELL AS THE TROPICAL ATLC NEAR 13N31W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ WALTON