000 AXNT20 KNHC 292333 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT WED JUL 29 2009 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... A TROPICAL WAVE IS ALONG 29W/30W S OF 23N MOVING W 10-15 KT. SATELLITE IMAGERY AND SATELLITE DERIVED WINDS INDICATE LOW/MID-LEVEL CYCLONIC FLOW IN THE VICINITY OF THE WAVE AXIS. THIS WAVE ALSO LEADS A HIGH AMPLITUDE DEEP LAYER MOISTURE MAXIMUM OBSERVED IN TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED MODERATE CONVECTION IS FROM 9N-11N BETWEEN 30W-32W. A TROPICAL WAVE IS ALONG 59W S OF 18N MOVING W NEAR 20 KT. THIS WAVE COINCIDES WITH A DEEP LAYER MOISTURE MAXIMUM OBSERVED IN TOTAL PRECIPITABLE WATER IMAGERY. NO DEEP CONVECTION IS CURRENTLY ASSOCIATED WITH THIS WAVE. HOWEVER...SCATTERED SHOWERS ARE FROM 12N-16N BETWEEN 57W-63W...AFFECTING THE LESSER ANTILLES. A TROPICAL WAVE IS ALONG 87W S OF 20N MOVING W NEAR 25 KT. THIS WAVE LIES IN A BROAD AREA OF DEEP LAYER MOISTURE OBSERVED IN TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 10N-23N BETWEEN 83W-90W. THIS CONVECTION IS ENHANCED BY ATMOSPHERIC INSTABILITY AND UPPER LEVEL DIFFLUENCE. ...ITCZ... THE ITCZ AXIS IS CENTERED ALONG 12N16W 11N27W 9N40W 11N57W 10N64W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 10N-13N BETWEEN 14W-18W. SCATTERED MODERATE CONVECTION IS FROM 9N-11N BETWEEN 22W-26W. ...DISCUSSION... GULF OF MEXICO... ISOLATED SHOWERS/THUNDERSTORMS ARE ACROSS THE NRN GULF OF MEXICO N 29N DUE TO UPPER LEVEL DIFFLUENCE BETWEEN AN UPPER LEVEL TROUGH OVER THE ERN CONUS AND AN UPPER LEVEL HIGH OVER THE CENTRAL GULF NEAR 26N87W. SCATTERED SHOWERS/THUNDERSTORMS ARE ALSO ACROSS THE ERN GULF OF MEXICO E OF 27W INCLUDING THE FLORIDA PENINSULA DUE TO UPPER LEVEL DIFFLUENCE BETWEEN THE UPPER LEVEL HIGH OVER THE CENTRAL GULF AND A SHORTWAVE UPPER LEVEL TROUGH JUST E OF THE FLORIDA PENINSULA WITH AXIS ALONG 78W. A TROPICAL WAVE ALONG 87W IS ENHANCING SCATTERED SHOWERS/THUNDERSTORMS ACROSS THE YUCATAN PENINSULA...WRN CUBA...AND THE ADJACENT WATERS S OF 23N E OF 91W. ELSEWHERE ACROSS THE GULF...A BROAD SURFACE RIDGE DOMINATES BRINGING GENERALLY FAIR WEATHER. DRY AIR AND SUBSIDENCE ALOFT SUPPORT THE SURFACE RIDGE. ANTI-CYCLONIC SURFACE FLOW IS AROUND THE RIDGE WITH WINDS REACHING 15-20 KT IN THE WRN GULF. EXPECT THE SURFACE RIDGE TO LIFT N OF 30N BY MONDAY. CARIBBEAN SEA... A TROPICAL WAVE ALONG 87W IS GENERATING SCATTERED SHOWERS/THUNDERSTORMS ACROSS THE WRN CARIBBEAN FROM 10N-23N BETWEEN 83W-90W INCLUDING MUCH OF CENTRAL AMERICA...THE YUCATAN PENINSULA AND WRN CUBA. ATMOSPHERIC INSTABILITY FROM DAYTIME HEATING AND DIFFLUENT FLOW ALOFT ARE ENHANCING THIS ACTIVITY. SCATTERED SHOWERS/THUNDERSTORMS ARE ALSO ACROSS CENTRAL AND WRN CUBA N OF 21N BETWEEN 76W-83W DUE TO DIFFLUENT FLOW NEAR THE SHORTWAVE UPPER LEVEL TROUGH IN THE WRN ATLC ALONG 78W THAT EXTENDS ACROSS CUBA TO 20N79W. SCATTERED SHOWERS/THUNDERSTORMS ARE ALSO IN THE S CENTRAL CARIBBEAN S OF 10N BETWEEN 76W-83W INCLUDING MOST OF PANAMA. THIS ACTIVITY IS ENHANCED BY SURFACE CONVERGENCE IN THE PROXIMITY OF THE E PACIFIC ITCZ. ELSEWHERE ACROSS THE CARIBBEAN...DRY AIR AND SUBSIDENCE ALOFT ARE PRODUCING GENERALLY FAIR WEATHER...EXCEPT FOR SCATTERED SHOWERS S OF 16N E OF 63W INFLUENCED BY THE APPROACHING TROPICAL WAVE CURRENTLY ALONG 59W. FRESH TO STRONG TRADE WINDS ARE ACROSS MUCH OF THE CARIBBEAN WITH THE STRONGEST NEAR THE COAST OF COLUMBIA WHERE A GALE WARNING IS CURRENTLY IN EFFECT. THE GALE FORCE WINDS ARE EXPECTED TO CONTINUE THROUGH EARLY TOMORROW MORNING. ATLANTIC OCEAN... A SHORTWAVE UPPER LEVEL TROUGH ALONG 78W IS ENHANCING SCATTERED SHOWERS/THUNDERSTORMS NW OF A LINE FROM 23N80W TO 30N73W. THE REMAINDER OF THE ATLC IS DOMINATED BY DRY STABLE AIR AND A BROAD SURFACE RIDGE ANCHORED BY A 1026 MB SURFACE HIGH NEAR 33N57W BRINGING GENERALLY FAIR WEATHER ACROSS THE BASIN...EXCEPT FOR AN AREA OF CLOUDINESS N OF THE TROPICAL WAVE ALONG 29W/30W FROM 23N-29N BETWEEN 22W-32W. $$ WALTON