000 AXNT20 KNHC 300000 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT SAT AUG 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 2330 UTC. ...TROPICAL WAVES... A TROPICAL WAVE IS ALONG 23W S OF 17N MOVING W NEAR 10 KT. A MID LEVEL CYCLONIC ROTATION IS OBSERVED ALONG THE WAVE NEAR 15N. THE WAVE COINCIDES WITH A DEEP LAYER MOISTURE MAXIMUM OBSERVED IN TOTAL PRECIPITABLE WATER IMAGERY. A RECENT CLUSTER OF SCATTERED MODERATE/STRONG CONVECTION IS FROM 14N-16N BETWEEN 21W-23W. AN ELONGATED TROPICAL WAVE EXTENDS FROM 15N38W SW TO A 1011 MB SURFACE LOW NEAR 10N42W CONTINUING WSW TO 8N49W. THIS SYSTEM IS MOVING W NEAR 15 KT. THIS WAVE/LOW IS WITHIN A VERY BROAD AREA OF CYCLONIC FLOW AS INDICATED ON VISIBLE SATELLITE IMAGERY. THE WAVE ALSO COINCIDES WITH AN ELONGATED DEEP LAYER MOISTURE MAXIMUM OBSERVED IN TOTAL PRECIPITABLE WATER IMAGERY. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE 7N-8N BETWEEN 45W-48W...9N-11N BETWEEN 41W-45W...AND 11N-16N BETWEEN 43W-46W. A TROPICAL WAVE IS ALONG 61W S OF 16N MOVING W NEAR 15 KT. THE WAVE FOLLOWS AN AREA OF RELATIVELY INCREASED MOISTURE OBSERVED IN TOTAL PRECIPITABLE WATER IMAGERY. HOWEVER...THE WAVE IS CURRENTLY EMBEDDED WITHIN AN AREA OF DRY STABLE AIR INHIBITING ANY DEEP CONVECTION. ...ITCZ... THE ITCZ AXIS IS CENTERED ALONG 15N16W 12N27W 15N36W 7N50W 10N60W. SCATTERED MODERATE CONVECTION IS FROM 10N-12N BETWEEN 25W-28W. ...DISCUSSION... GULF OF MEXICO... A SURFACE TROUGH EXTENDS ACROSS S FLORIDA INTO THE CENTRAL GULF ALONG 27N80W TO 26N88W. SCATTERED SHOWERS/THUNDERSTORMS ARE WITHIN 100 NM EITHER SIDE OF THE TROUGH AXIS. THIS ACTIVITY IS ENHANCED MAINLY BY UPPER LEVEL DIFFLUENCE BETWEEN AN UPPER LEVEL RIDGE CENTERED NEAR 17N98W ASSOCIATED WITH HURRICANE JIMENA IN THE E PACIFIC AND A BROAD UPPER LEVEL TROUGH ACROSS THE ERN CONUS WHICH COVERS THE NRN GULF N OF 25N. THE UPPER LEVEL RIDGE IS DRAWING MOISTURE FROM THE E PACIFIC ACROSS THE WRN GULF GENERATING A FEW ISOLATED SHOWERS ACROSS THE SW GULF. UPPER LEVEL DIFFLUENCE BETWEEN AN UPPER LEVEL LOW OVER THE W CARIBBEAN NEAR 15N82W AND AN UPPER LEVEL RIDGE IN THE W ATLC IS SUPPORTING SCATTERED SHOWERS/THUNDERSTORMS OVER CUBA AND THE STRAITS OF FLORIDA S OF 24N. A FEW ISOLATED SHOWERS/THUNDERSTORMS ARE IN THE FAR NW GULF N OF 29N W OF 93W AHEAD OF A COLD FRONT ACROSS TEXAS. EXPECT THIS FRONTAL BOUNDARY TO MOVE INTO THE NW GULF LATE SUN. CARIBBEAN SEA... AN UPPER LEVEL LOW IS OVER THE W CARIBBEAN CENTERED NEAR 15N82W. UPPER LEVEL DIFFLUENCE BETWEEN THIS LOW AND THE RIDGE OVER THE GULF OF MEXICO IS SUPPORTING SCATTERED SHOWERS/THUNDERSTORMS OVER THE YUCATAN PENINSULA S OF 22N W OF 87W. UPPER LEVEL DIFFLUENCE BETWEEN THE UPPER LOW AND AN UPPER LEVEL RIDGE OVER THE E CARIBBEAN E OF 77W...ALONG WITH MOIST SLY FLOW ALOFT ARE SUPPORTING NUMEROUS SHOWERS/THUNDERSTORMS ACROSS THE FAR SW CARIBBEAN S OF 12N BETWEEN 73W-84W...ISOLATED SHOWERS N OF 12N BETWEEN 77W-81W...AND SCATTERED SHOWERS/THUNDERSTORMS ACROSS CUBA N OF 21N BETWEEN 77W-85W. THE REMAINDER OF THE CARIBBEAN IS EXPERIENCING GENERALLY FAIR WEATHER UNDER THE INFLUENCE OF DRY AIR AND SUBSIDENCE ALOFT. A FEW ISOLATED SHOWERS ARE ACROSS PUERTO RICO AND HISPANIOLA DUE TO EARLIER DAYTIME HEATING. FRESH TO STRONG TRADE WINDS ARE ACROSS MUCH OF THE BASIN WITH THE STRONGEST WINDS NEAR THE COAST OF COLOMBIA. EXPECT THE WEAK TROPICAL WAVE CURRENTLY ALONG 61W TO PROGRESS WWD ACROSS THE E CARIBBEAN LATER TONIGHT. ATLANTIC OCEAN... A LARGE SURFACE TROUGH IS ACROSS THE W ATLC EXTENDING FROM A 1004 MB LOW...THE REMNANTS OF DANNY...OFF THE COAST OF MARYLAND. THE TROUGH ENTERS THE DISCUSSION AREA NEAR 32N73W EXTENDING TO THE COAST OF FLORIDA NEAR 27N80W AND CONTINUING INTO THE GULF OF MEXICO. SURFACE CONVERGENCE NEAR THE TROUGH IS SUPPORTING A LARGE AREA OF SCATTERED SHOWERS/THUNDERSTORMS ALONG THE COAST OF FLORIDA FROM 26N-29N BETWEEN 79W-81W. SCATTERED SHOWERS/THUNDERSTORMS ARE ALSO FROM 27W-31W BETWEEN 71W-73W. THE TROUGH IS SUPPORTED BY AN UPPER LEVEL TROUGH ACROSS THE ERN CONUS. THE SHOWER ACTIVITY NEAR THE FRONT IS ENHANCED BY UPPER LEVEL DIFFLUENCE BETWEEN THIS UPPER LEVEL TROUGH AND AN UPPER LEVEL RIDGE BETWEEN 65W-75W. A SHORTWAVE UPPER LEVEL TROUGH EXTENDS INTO THE UPPER RIDGE FROM 28N64W TO 22N56W CONTINUING TO AN UPPER LEVEL LOW NEAR 28N47W. UPPER LEVEL DIFFLUENCE NEAR THE SHORTWAVE UPPER TROUGH IS SUPPORTING ISOLATED SHOWERS FROM 20N-28N BETWEEN 56W-65W. ELSEWHERE ACROSS THE ATLC...A BROAD SURFACE RIDGE DOMINATES ANCHORED BY A 1026 MB HIGH NEAR 34N45W BRINGING GENERALLY FAIR WEATHER ACROSS THE BASIN. ACROSS THE TROPICAL ATLC...A BROAD UPPER LEVEL RIDGE IS CENTERED NEAR 17N39W ENHANCING CONVECTION ALONG THE ITCZ AND THE TROPICAL WAVE EXTENDING FROM 15N38W SW TO A 1011 MB SURFACE LOW NEAR 10N42W CONTINUING WSW TO 8N49W. $$ WALTON