000 AXNT20 KNHC 111039 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT SAT AUG 11 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1015 UTC. ...TROPICAL WAVES... HIGH AMPLITUDE TROPICAL WAVE IS JUST MOVING OUT OF THE AFRICAN COAST. IT AXIS IS ALONG 16W S OF 20N WITH A 1006 MB LOW PRES NEAR 11N. CONVECTION HAS SLIGHTLY DIMINISHED EARLY THIS MORNING. SATELLITE IMAGERY SHOWS SCATTERED MODERATE CONVECTION FROM 8N TO 13N E OF 20W. SOME OF THE COMPUTER MODELS CONTINUE TO DEVELOP THIS LOW INTO A TROPICAL CYCLONE AS IT MOVES WNW ACROSS THE ATLANTIC OCEAN ALONG THE PERIPHERY OF THE SUBTROPICAL RIDGE. VIS SATELLITE IMAGERY EARLY THIS MORNING INDICATES THAT THE SFC LOW IS NEAR 11N18W. WEAK TROPICAL WAVE IS ALONG 29W S OF 16N MOVING W 5-10 KT. SATELLITE IMAGES SHOW LITTLE WAVE SIGNATURE...WITH ONLY SCATTERED SHOWERS CONFINED TO THE ITCZ. TROPICAL WAVE IS ALONG 45W S OF 14N MOVING W 10-15 KT. THIS LOW AMPLITUDE WAVE REMAINS WEAK CAUSING A VERY SLIGHT PERTURBATION IN THE ITCZ. SCATTERED SHOWERS ARE ASSOCIATED WITH THIS FEATURE. HIGH AMPLITUDE TROPICAL WAVE IS ALONG 68W S OF 21N MOVING W NEAR 15 KT. THIS FEATURE IS OVER EASTERN DOMINICAN REPUBLIC PRODUCING A CLUSTER OF MODERATE TO ISOLATED STRONG CONVECTION. SANTO DOMING0 REPORTED TSRA DURING THE PAST FEW HOURS AND RAIN WILL BE ON INCREASE AS THE TROPICAL WAVE MOVES ACROSS THE ISLAND TODAY. THE SAN JUAN DOPPLER RADAR DEPICTS SCATTERED SHOWERS AND ISOLATED TSTMS BEHIND THE WAVE AXIS AFFECTING MAINLY THE MONA PASSAGE. AS THE DAY GOES ON...MOISTURE FROM THIS WAVE SHOULD SPREAD FIRST OVER THE REMAINDER OF HISPANIOLA AND AFTERWARD OVER THE BAHAMAS AND EASTERN CUBA. TROPICAL WAVE IS ALONG 76W S OF 19N MOVING W 10-15 KT. THIS WAVE IS GENERATING SCATTERED SHOWERS AND TSTMS OVER THE CENTRAL CARIBBEAN FROM 13N TO 17N AND A CLUSTER OF MODERATE TO ISOLATED STRONG CONVECTION BETWEEN JAMAICA AND E CUBA. KINGSTON HAS BEEN REPORTED SHOWERS AND TSTMS DURING THE PAST SEVERAL HOURS. THE SSMI-DERIVED TOTAL PRECIPITABLE WATER SHOW AN ENHANCED WWD MOVING MOISTURE SURGE IN AN ALREADY HIGH TPW ENVIRONMENT. TROPICAL WAVE IS NEAR THE MEXICO/GUATEMALA BORDER ALONG 91W S OF 22N MOVING W 10-15 KT. THE WAVE...COUPLED WITH THE EPAC ITCZ IS GENERATING CLUSTERS OF MODERATE TO STRONG CONVECTION FROM 10N-14N BETWEEN 87W-92W. THIS CONVECTIVE ACTIVITY IS AFFECTING THE EASTERN HALF OF EL SALVADOR AND THE SOUTHERN PORTION OF GUATEMALA...INCLUDING THE COASTAL WATERS. THIS WAVE LIES UNDERNEATH AN UPPER LOW...WHICH IS HELPING TO GENERATE THIS SHOWER/TSTMS ACTIVITY. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 10N18W 11N27W 11N36W 9N50W 11N60W. OUTSIDE THE CONVECTION ASSOCIATED WITH THE TROPICAL WAVE NEAR THE AFRICAN COAST...SCATTERED MODERATE CONVECTION IS NEAR 7N23W AND WITHIN 150 NM SOUTH OF THE AXIS BETWEEN 32W-38W. DISCUSSION... GULF OF MEXICO... THE COMBINATION OF A STRONG UPPER HIGH OVER THE SRN U.S. AND AN UPPER LOW OVER THE SW CORNER OF THE GULF NEAR 21N95W CONTINUES TO PRODUCE STRONG UPPER E TO NE WIND FLOW ACROSS THE GULF. SCATTERED SHOWERS ARE OVER THE SW GULF CAUSED BY INSTABILITY NEAR THE UPPER LOW AND A NEARBY TROPICAL WAVE. SCATTERED SHOWERS AND ISOLATED TSTMS ARE ALSO OVER THE SE GULF...THE FLORIDA KEYS AND CUBA TRIGGERED BY A SFC TROUGH WHICH EXTENDS NWD FROM THE CARIB ACROSS W CUBA INTO SE PORTION OF THE GULF. THE SFC PATTERN REMAINS WEAK WITH A QUASI-STATIONARY 1014 MB HIGH CENTER NEAR 28N93W. THIS WEAK PRES GRAD IS EXPECTED TO CONTINUE FOR A FEW MORE DAYS ALLOWING WINDS TO REMAIN LIGHT. THE UPPER LOW IS FORECAST TO MOVE WWD ACROSS CENTRAL MEXICO LATE TODAY. CARIBBEAN SEA... A CONSIDERABLE AMOUNT OF MOISTURE REMAINS OVER THE CARIBBEAN EARLY THIS MORNING. SEVERAL UPPER LEVEL FEATURES ARE ENHANCING THIS MOISTURE. THEY ARE...THE UPPER LOW OVER THE SW GULF OF MEXICO...TWO UPPER HIGHS NEAR 20N84W AND 14N65W AND ANOTHER UPPER LOW NEAR THE CENTRAL BAHAMAS. WITHIN THIS MOIST UPPER ENVIRONMENT THERE ARE TWO TROPICAL WAVES AND A SFC TROUGH HELPING TO PROVIDE EVEN MORE LIFT. SCATTERED SHOWERS ARE OVER THE FAR SE CARIBBEAN AND OVER PARTS OF CENTRAL AMERICA DUE TO THE PASSAGE OF A TROPICAL WAVE CURRENTLY LOCATED OVER THE MEXICO/GUATEMALA BORDER. LIGHT TO MODERATE WINDS ARE FOUND IN THE WRN PORTION OF THE BASIN AND MODERATE TO FRESH TRADE WINDS IN THE E AND CENTRAL CARIB. ATLANTIC OCEAN... UPPER DIFFLUENCE BETWEEN AN UPPER LOW NEAR THE CENTRAL BAHAMAS AND AN UPPER HIGH OVER THE E CARIB IS SUPPORTING AN AREA OF SHOWERS WITH EMBEDDED TSTMS OVER THE SW ATLC NEAR THE SE BAHAMAS AND HISPANIOLA. FARTHER E...AN UPPER TROUGH EXTENDS SW ACROSS THE CENTRAL ATLC FROM AN UPPER LOW LOCATED NEAR 27N43W. RIDGING COVERS THE REMAINDER OF THE ATLC STRETCHING W FROM AN UPPER HIGH LOCATED NEAR MIDWAY BETWEEN THE CANARY AND CAPE VERDE ISLANDS. THERE IS LITTLE MOISTURE ASSOCIATED WITH EITHER THE RIDGE OR TROUGH. WV IMAGERY SHOWS ABUNDANT DRY AIR/SUBSIDENCE ALOFT E OF 50W...ALLOWING FAIR WEATHER TO PREVAIL. AT THE SFC...THE MAIN WEATHER FEATURE IS A STATIONARY 1025 MB HIGH CENTERED NEAR 36N34W. THIS HIGH EXTENDS A RIDGE SW REACHING THE NE CARIBBEAN AND THE BAHAMAS. IT IS PRODUCING LIGHT TO MODERATE TRADES ACROSS THE BULK OF THE ATLC DISCUSSION AREA. $$ GR