000 AXNT20 KNHC 082356 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT SAT AUG 08 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 2315 UTC. ...TROPICAL WAVES... A TROPICAL WAVE IS ALONG 17W S OF 16N MOVING W NEAR 15 KT. RECENT SATELLITE IMAGERY INDICATES A WELL-DEFINED LOW/MID-LEVEL CYCLONIC CIRCULATION CENTER ALONG THE WAVE AXIS NEAR 12N. MODEL GUIDANCE ANALYSES DEPICT THE LOW-LEVEL VORTICITY MAXIMUM ASSOCIATED WITH THIS WAVE TRACKING WWD ACROSS WRN GUINEA AND GUINEA-BISSAU OVER W AFRICA DURING THE LAST 6-12 HOURS. AS THE WAVE HAS EMERGED OFF THE W AFRICA COAST...A BAND OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 11N-16N BETWEEN 16W-21W. A TROPICAL WAVE EXTENDS FROM 8N23W TO 17N35W MOVING W NEAR 23 KT. THIS WAVE IS EMBEDDED WITHIN A WELL-DEFINED MAXIMUM IN DEEP LAYER MOISTURE THAT REMAINS TILTED IN A SE TO NW ORIENTATION BASED ON THE TPW PRODUCT FROM CIMSS. RECENT SATELLITE IMAGERY DEPICTS CYCLONIC MOTION OF LOW LEVEL CLOUDS IN THE VICINITY OF THIS WAVE...MAINLY FROM 11N-17N. SCATTERED MODERATE CONVECTION IS FROM 7N-10N BETWEEN 20W-26W. A TROPICAL WAVE IS ALONG 44W S OF 16N MOVING W NEAR 15 KT. THIS WAVE COINCIDES WITH AN INVERTED-V SATELLITE SIGNATURE IN THE LOW-LEVEL CLOUD FIELD...HOWEVER DRY AIR ALOFT AND ATMOSPHERIC STABILITY IN THE VICINITY OF AN UPPER LEVEL RIDGE ARE LIMITING DEEP CONVECTION NEAR THIS WAVE. HOWEVER...ISOLATED MODERATE CONVECTION IS FROM 9N-12N BETWEEN 41W-44W. A TROPICAL WAVE IS ALONG 60W S OF 17N MOVING W NEAR 13 KT. SATELLITE-DERIVED WINDS INDICATE CYCLONIC CURVATURE IN THE FLOW WITHIN THE 950-800 MB LAYER NEAR THIS WAVE. THE CIMSS WAVETRAK PRODUCT ALSO CONFIRMS THAT THIS WAVE COINCIDES WITH A MAXIMUM IN LOW-LEVEL CYCLONIC CIRCULATION. SCATTERED SHOWERS AND ISOLATED MODERATE CONVECTION IS FROM 10N-14N BETWEEN 58W-63W. A TROPICAL WAVE IS ALONG 80W S OF 21N MOVING W NEAR 20 KT. THIS WAVE COINCIDES WITH A MAXIMUM IN DEEP LAYER MOISTURE BASED ON THE TPW PRODUCT FROM CIMSS. SATELLITE IMAGERY INDICATES CURVATURE IN LOW-LEVEL CLOUD BANDS ALONG THE WAVE AXIS. MIDDLE TO UPPER LEVEL DRY AIR IS INHIBITING THE AREAL COVERAGE OF DEEP CONVECTION NEAR THIS WAVE. HOWEVER...SCATTERED MODERATE CONVECTION IS S OF 11N ACROSS THE SW CARIBBEAN AND WELL TO THE W OF THE WAVE AXIS ACROSS NICARAGUA AND HONDURAS FROM 11N-16N BETWEEN 82W-88W. A TROPICAL WAVE IS ALONG 96W S OF 21N MOVING W NEAR 15 KT. THIS WAVE IS EMBEDDED WITHIN A BROAD AREA OF DEEP LAYER MOISTURE BASED ON THE TPW PRODUCT FROM CIMSS. ALTHOUGH THE WAVE CONTINUES TO TRACK WWD BENEATH AN UPPER LEVEL DIFFLUENT PATTERN...MOST CONVECTION ASSOCIATED WITH THE WAVE REMAINS S OF 17N AND INTO THE E PACIFIC REGION. A FEW ISOLATED MODERATE CONVECTIVE CELLS ARE OVER SRN MEXICO BETWEEN 92W-97W. ...ITCZ... THE ITCZ AXIS IS CENTERED ALONG 13N18W 10N24W 10N27W 10N43W 13N49W 10N59W. A SURFACE TROUGH MOVING WWD NEAR 10 KT IS EMBEDDED WITHIN THE ITCZ AND EXTENDS FROM 10N52W TO 17N48W WITH WIDELY SCATTERED MODERATE CONVECTION FROM 11N-16N BETWEEN 52W-56W. ...DISCUSSION... GULF OF MEXICO... AN UPPER LEVEL TROUGH AXIS EXTENDS NEWD FROM CENTRAL MEXICO ALONG THE TEXAS GULF COAST TO AN UPPER LEVEL VORTICITY MAXIMUM OVER LOUISIANA NEAR 31N91W. ATMOSPHERIC INSTABILITY AND DEEP LAYER MOISTURE ASSOCIATED WITH SLY FLOW ALOFT E OF THE TROUGH AXIS IS SUPPORTING SCATTERED SHOWERS AND ISOLATED TSTMS N OF 24N BETWEEN 84W-96W. A PORTION OF THIS ACTIVITY IS BEING ENHANCED BY LOW LEVEL CONVERGENCE FOCUSED NEAR A SURFACE TROUGH EXTENDING FROM THE FLORIDA PANHANDLE NEAR 30N86W TO 27N91W. AN EARLIER ASCAT PASS AROUND 1530 UTC CONFIRMED CYCLONIC CURVATURE NEAR THE SURFACE TROUGH AXIS. ACROSS THE SE GULF...STABLE ATMOSPHERIC CONDITIONS ASSOCIATED WITH AN UPPER LEVEL RIDGE EXTENDING FROM THE SE CONUS ACROSS FLORIDA AND THE STRAITS OF FLORIDA ARE RESULTING IN GENERALLY FAIR WEATHER. CARIBBEAN SEA... UPPER LEVEL DIFFLUENCE IN NELY FLOW ALOFT OVER THE NW CARIBBEAN IS SUPPORTING SCATTERED SHOWERS AND TSTMS OVER CENTRAL AMERICA S OF 17N AND W OF THE TROPICAL WAVE ALONG 80W. DRY AIR ALOFT RESIDES TO THE NE OF THIS CONVECTIVE AREA WITH ONLY EARLY EVENING ISOLATED SHOWERS AND TSTMS REMAINING OVER CUBA AND THE NEARBY SRN COASTAL CARIBBEAN WATERS. OVER THE CENTRAL CARIBBEAN...AN UPPER LEVEL TROUGH AXIS EXTENDS FROM HISPANIOLA NEAR 18N72W TO PANAMA. DEEP LAYER DRY AIR EMBEDDED WITHIN THIS UPPER LEVEL TROUGH IS INHIBITING DEEP CONVECTION NEAR THIS UPPER TROUGH CORRIDOR. HOWEVER...SCATTERED SHOWERS AND ISOLATED TSTMS REMAINS S OF 11N IN THE VICINITY OF THE TROPICAL WAVE ALONG 80W. ACROSS THE E CARIBBEAN...DEEP LAYER DRY AIR IS RESULTING IN GENERALLY FAIR WEATHER. HOWEVER...SCATTERED SHOWERS AND TSTMS ARE OCCURRING S OF 13N E OF 67W...INCLUDING NRN VENEZUELA. THIS ACTIVITY IS BEING SUPPORTED BY LOW LEVEL CONVERGENCE NEAR THE ITCZ AXIS AND THE APPROACH OF THE TROPICAL WAVE ALONG 60W. THE SURFACE PRESSURE GRADIENT S OF A SURFACE RIDGE OVER THE CENTRAL ATLC IS SUPPORTING FRESH TO STRONG TRADE WINDS ACROSS MUCH OF THE CARIBBEAN BASIN. THE STRONGEST WINDS ARE NEAR THE COAST OF COLOMBIA...WHERE NE WINDS OF 25 TO 30 KT ARE OCCURRING. ATLANTIC OCEAN... AN UPPER LEVEL SHORTWAVE TROUGH AXIS IS OVER THE SW NORTH ATLC AND EXTENDS FROM 27N80W TO 28N73W TO 30N70W TO NE OF THE DISCUSSION AREA. ATMOSPHERIC LIFT S OF THIS UPPER LEVEL SHORTWAVE TROUGH AXIS IS SUPPORTING A SURFACE TROUGH EXTENDING FROM THE NW BAHAMAS NEAR 27N78W TO 31N71W IN THE VICINITY OF A STATIONARY FRONTAL BOUNDARY ALONG 32N BETWEEN 70W-80W. LOW LEVEL CONVERGENCE NEAR THE SURFACE TROUGH AND ATMOSPHERIC INSTABILITY ASSOCIATED WITH THE UPPER LEVEL SHORTWAVE TROUGH ARE SUPPORTING SCATTERED SHOWERS AND ISOLATED TSTMS WITHIN 200 NM SE OF THE SURFACE TROUGH. TO THE E...AN UPPER LEVEL LOW IS CENTERED NEAR 32N47W WITH AN ASSOCIATED SURFACE TROUGH EXTENDING FROM 24N51W TO 31N51W. LOW LEVEL CONVERGENCE NEAR THIS SURFACE TROUGH AND ATMOSPHERIC INSTABILITY NEAR THE UPPER LEVEL LOW ARE SUPPORTING SCATTERED SHOWERS N OF 27N BETWEEN 43W-53W. THE REMAINDER OF THE CENTRAL AND ERN ATLC IS CONTROLLED BY A DEEP LAYER RIDGE ANCHORED BY A 1029 MB SURFACE HIGH NEAR 36N37W. STABLE ATMOSPHERIC CONDITIONS IN THE VICINITY OF THIS DEEP LAYER RIDGE ARE RESULTING IN GENERALLY FAIR WEATHER ACROSS MUCH OF THE CENTRAL AND E ATLC. $$ HUFFMAN