000 AXNT20 KNHC 241737 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT MON AUG 24 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1700 UTC. ...TROPICAL WAVES... A TROPICAL WAVE IS ALONG 28W S OF 19N MOVING W NEAR 18 KT. VISIBLE SATELLITE IMAGERY...AN 1144 UTC ASCAT SCATTEROMETER PASS...AND SATELLITE DERIVED WINDS INDICATE GOOD LOW-LEVEL CYCLONIC FLOW IN THE VICINITY OF THE WAVE AXIS. THIS WAVE ALSO IS AHEAD OF A DEEP LAYER MOISTURE MAXIMUM OBSERVED IN TOTAL PRECIPITABLE WATER IMAGERY. A DRY SAHARAN AIR LAYER IS TO THE E OF THE AXIS CURRENTLY INHIBITING DEEP CONVECTION NEAR THE WAVE. AN ACTIVE TROPICAL WAVE IS ALONG 56W S OF 20N MOVING W NEAR 18 KT. AN INVERTED-V FEATURE IS APPARENT IN THE LOW-LEVEL CLOUD STRUCTURE IN VISIBLE SATELLITE IMAGERY. THE WAVE ALSO COINCIDES WITH A DEEP LAYER MOISTURE MAXIMUM OBSERVED IN TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 15N-22N BETWEEN 52W-58W. THIS ACTIVITY IS ENHANCED BY UPPER LEVEL DIFFLUENCE. A TROPICAL WAVE IS ALONG 74W S OF 20N MOVING W 15-20 KT. THIS WAVE LIES IN A BROAD AREA OF DEEP LAYER MOISTURE THAT RANGES FROM THE COAST OF VENEZUELA TO ERN PANAMA. LOW-LEVEL CYCLONIC FLOW IS ALSO BROAD OVER THIS SAME AREA. DUE TO THE BROAD SURFACE FLOW...CONFIDENCE IN THE EXACT LOCATION OF THE WAVE IS LOW AND THE WAVE MAY BE FARTHER WEST. SCATTERED MODERATE CONVECTION IS FROM 13N-15N BETWEEN 69W-72W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 9N-15N BETWEEN 76W-82W. THE ITCZ... THE ITCZ AXIS IS CENTERED ALONG 13N15W 14N27W 9N39W 13N54W 9N64W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 12N-17N BETWEEN 16W-25W. ...DISCUSSION... THE GULF OF MEXICO... A STATIONARY FRONT DIPS ACROSS THE N AND CENTRAL GULF EXTENDING FROM CENTRAL FLORIDA NEAR 29N81W TO 25N87W CONTINUING TO THE TEXAS COAST TO NEAR 29N95. THE FRONT IS SUPPORTED BY AN UPPER LEVEL TROUGH ACROSS THE ERN CONUS WHICH EXTENDS ACROSS THE NRN GULF TO NEAR 25N96W. THE FRONT IS SUPPORTING SCATTERED SHOWERS/THUNDERSTORMS ACROSS THE NW GULF FROM 27N-30N BETWEEN 91W-96W. DRY AIR AND SUBSIDENCE ALOFT BEHIND THE FRONT ARE BRINGING THE REMAINDER OF THE NRN GULF GENERALLY FAIR WEATHER. ISOLATED SHOWERS/THUNDERSTORMS ARE ACROSS THE SRN GULF S OF 26N EXTENDING FROM THE BAY OF CAMPECHE TO S FLORIDA. THIS ACTIVITY IS ENHANCED BY UPPER LEVEL DIFFLUENCE AND MOIST SWLY FLOW ALOFT BETWEEN THE UPPER LEVEL TROUGH OVER THE NRN GULF AND AN UPPER LEVEL RIDGE ACROSS THE SRN GULF LINKED TO AN UPPER LEVEL HIGH OVER CUBA NEAR 23N80W. EXPECT THE FRONT TO GRADUALLY DISSIPATE OVER THE W GULF BY TUE NIGHT. THE CARIBBEAN SEA... ISOLATED SHOWERS/THUNDERSTORMS ARE N OF HONDURAS FROM 16N-18N BETWEEN 82W-89W. THIS ACTIVITY MAY BE ENHANCED BY THE BROAD CYCLONIC FLOW AROUND THE TROPICAL WAVE ALONG 74W. THE TROPICAL WAVE IS ALSO ENHANCING SHOWERS/THUNDERSTORMS ACROSS THE SW AND S CENTRAL CARIBBEAN...SEE ABOVE. THIS ACTIVITY IS ALSO ENHANCED BY SURFACE CONVERGENCE NEAR THE E PACIFIC ITCZ AND A 1007 MB LOW OVER PANAMA NEAR 8N78W. DRY AIR AND SUBSIDENCE ALOFT AROUND THE UPPER LEVEL HIGH OVER CUBA NEAR 23N80W IS BRINGING GENERALLY FAIR WEATHER ACROSS THE REMAINDER OF THE CENTRAL CARIBBEAN. A FEW ISOLATED SHOWERS/POSSIBLE THUNDERSTORMS ARE ACROSS PUERTO RICO AND THE LESSER ANTILLES DUE TO UPPER LEVEL DIFFLUENCE BETWEEN AN UPPER LEVEL LOW IN THE ATLC NEAR 26N63W AND AN UPPER LEVEL HIGH TO E NEAR 19N45W. EXPECT A TROPICAL WAVE CURRENTLY ALONG 56W TO REACH THE NE CARIBBEAN LATER TONIGHT. THE ATLANTIC OCEAN... A STATIONARY FRONT ACROSS CENTRAL FLORIDA EXTENDS FROM 29N81W TO 31N80W CONTINUING NNE AS A COLD FRONT. SCATTERED SHOWERS/THUNDERSTORMS ARE WITHIN 200 NM AHEAD OF THE FRONT AFFECTING THE NW BAHAMAS. THIS ACTIVITY IS ALSO SUPPORTED BY UPPER LEVEL DIFFLUENCE BETWEEN THE STRONG UPPER LEVEL TROUGH OVER THE ERN CONUS AND AN UPPER LEVEL RIDGE THAT EXTENDS FROM AN UPPER LEVEL HIGH OVER CUBA NEAR 23N80W. TO THE E OF THE RIDGE A STRONG UPPER LEVEL LOW IS CENTERED NEAR 26N63W. UPPER LEVEL DIFFLUENCE BETWEEN THIS LOW AND AN UPPER LEVEL HIGH NEAR 19N45W IS SUPPORTING SCATTERED SHOWERS/THUNDERSTORMS FROM 18N-26N BETWEEN 60W-67W. SHOWER ACTIVITY TO THE E OF THIS AREA IS SUPPORTED BY THE TROPICAL WAVE ALONG 56W...SEE ABOVE. ELSEWHERE ACROSS THE ATLC...A BROAD SURFACE RIDGE DOMINATES ANCHORED BY A 1027 MB HIGH NEAR 36N48W. $$ WALTON