000 AXNT20 KNHC 280518 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT SAT JUL 28 2007 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN SECTIONS OF SOUTH AMERICA...AND THE 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0515 UTC. ...TROPICAL WAVES... TROPICAL WAVE WAS ADDED TO THE SFC MAP AT 00Z ALONG 17W S OF 17N ESTIMATED TO MOVING W NEAR 10 KT. THERE ARE A FEW INDICATORS WHICH SUPPORT THIS FEATURE. SATELLITE IMAGERY SHOWS A PRONOUNCED AREA OF LOW TO MID LEVEL TURNING COVERING AN AREA ABOUT 4 DEG EITHER SIDE OF THE AXIS. SFC OBS OVER AFRICA ARE REPORTING A 1-2 MB DROP COMPARED TO YESTERDAY AT THIS TIME AND THE DAKAR SOUNDING SHOWS THE FLOW SHIFTING TO THE SE IN THE 700-925 MB LAYER ON THE 00Z SOUNDING. WITH THAT SAID...SHOWER ACTIVITY IS VERY MINIMAL AND MOSTLY INLAND OVER AFRICA. TROPICAL WAVE S OF 17N ALONG 36W SCATTERED MODERATE CONVECTION ALONG THE ITCZ FROM 11N-12N BETWEEN 34W-37W. TROPICAL WAVE FROM 6N-16N ALONG 49W/50W IS ADJUSTED W DO TO SATELLITE CLOUD STRUCTURE. ISOLATED SHOWERS ARE WITHIN 120 NM EITHER SIDE OF WAVE N OF 10N. TROPICAL WAVE IS MOVING INTO THE WRN CARIBBEAN ALONG 80W/81W S OF 18N MOVING W AROUND 15 KT. MODERATE TO STRONG CONVECTION ASSOCIATED WITH THE WAVE IS FROM 10N-13N BETWEEN 80W-82W. ...THE ITCZ... ITCZ AXIS IS ALONG 12N20W 11N27W 13N35W 11N40W 13N47W 8N59W. MODERATE TO ISOLATED STRONG CONVECTION WITHIN 180 NM S OF AXIS FROM 22W-26W. ...DISCUSSION... GULF OF MEXICO... UPPER LEVEL ANTICYCLONIC CIRCULATION CENTERED OVER W CENTRAL MEXICO WITH RIDGE EXTENDING FROM THE CIRCULATION NE TO THE TEXAS LOUISIANA BORDER...COMBINED WITH AND UPPER LOW OVER CENTRAL TEXAS IS PRODUCING DIFFLUENCE ALOFT AND ENHANCING TSTM ACTIVITY ACROSS MEXICO AND ADJACENT COASTAL WATERS FROM 21N-26N BETWEEN 96W-101W. ANTICYCLONIC FLOW COVERS MUCH OF THE GULF OF MEXICO WITH MAINLY DEBRIS CLOUDS FROM EARLIER CONVECTION N OF AROUND 24N. A COUPLE OF 1016 MB SURFACE HIGH PRES CENTERS ARE LOCATED NEAR 28N90W AND 29N84W. CARIBBEAN SEA... UPPER NE FLOW AROUND RIDGING DOMINATES THE NW PORTION. AN INVERTED UPPER TROUGH EXTENDS NE FROM COSTA RICA TO NEAR HAITI. A WEAK UPPER HIGH IS OFF THE COAST OF COLOMBIA NEAR 13N 73W. WHILE TROUGHING AND DRY UPPER AIR DOMINATES THE EASTERN CARIBBEAN E OF 70W. THERE IS A CLUSTER OF MODERATE TO STRONG CONVECTION OVER NORTHERN COLOMBIA RELATED TO A 1008 MB LOW PRES NEAR 9N75W. THE REMAINDER OF THE CARIBBEAN IS RATHER QUIET. ATLANTIC OCEAN... UPPER LEVEL TROUGH IS ALONG THE E COAST OF THE U.S. WITH SURFACE TROUGH FROM 31N74W TO THE NORTHERN BAHAMAS NEAR 24N77W. EARLIER CONVECTIVE ACTIVITY HAS DECREASED WITH SCATTERED SHOWERS REMAINING N OF 22N W OF 70W. UPPER LEVEL RIDGE E OF THE TROUGH EXTENDS FROM THE STRAITS OF FLORIDA NE TO 31N72W. DOWNSTREAM CYCLONIC CIRCULATION IS CENTERED NEAR 29N63W WITH SURFACE TROUGH FROM 31N58W TO 24N64W. ISOLATED SHOWERS ARE ROTATING AROUND THE UPPER LEVEL CYCLONIC CIRCULATION N OF 24N BETWEEN 57W-67W. LARGE SCALE UPPER RIDGING AND DRY/STABLE AIR DOMINATES MUCH OF THE E ATLC. A 1023 MB SFC HIGH IS NEAR 34N32W ALSO DOMINATES THE E-CENTRAL ATLC. FAIR WEATHER AND LIGHT TO MODERATE TRADES ARE FOUND UNDER THE INFLUENCE OF THIS RIDGE. $$ DGS