000 AXNT20 KNHC 231746 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT WED AUG 23 2006 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHEASTERN 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...WEATHER OBSERVATIONS...RADAR... AND METEOROLOGICAL ANALYSIS. BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...SPECIAL FEATURE... TROPICAL STORM DEBBY IS CENTERED NEAR 16.8N 31.5W 0R ABOUT 435 NM WEST OF THE CAPE VERDE ISLANDS AT 23/1500 UTC MOVING WNW AT 15 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1000 MB. MAXIMUM SUSTAINED WIND SPEED IS 45 KT WITH GUSTS TO 55 KT. SEE LATEST NHC FORECAST/ADVISORY UNDER HEADERS MIATCMAT4/WTNT24 KNHC FOR MORE DETAILS. DEBBY IS UNDERGOING SLOW DEVELOPMENT AND IS EXPECTED TO CONTINUE OVER THE NEXT FEW DAYS AS THE ENVIRONMENT HAS LIGHT SHEAR. HOWEVER...THE CONVECTION APPEARS TO BE WEAKENING AT THE CURRENT TIME WITH SCATTERED MODERATE CONVECTION COVERING THE AREA FROM 14N-18N BETWEEN 30W-34W. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 52W/53W S OF 20N WITH A 1012 MB LOW ALONG THE WAVE NEAR 11N MOVING W 15-20 KT. BROAD MID LEVEL ROTATION ALONG THE ITCZ AXIS. DESPITE ITS STRUCTURE...DEEP CONVECTION IS W OF THE WAVE AXIS AND CONFINED WITHIN THE ITCZ. THIS SYSTEM HAS THE POTENTIAL FOR FURTHER DEVELOPMENT IN THE NEXT FEW DAYS. HOWEVER...THE N EXTENSION OF THE WAVE REMAINS EMBEDDED IN A LARGE AREA OF AFRICAN DUST. TROPICAL WAVE IN THE E CARIBBEAN IS ALONG 66W/67W S OF 20N MOVING W 15 KT. ILL-DEFINED INVERTED-V SHAPE IS NOTED ON SATELLITE IMAGERY AS THE WAVE IS BENEATH A BROAD UPPER RIDGE. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS COVER A LARGE AREA FROM OVER THE ABC ISLANDS TO 17N BETWEEN 63W-71W. TROPICAL WAVE IN THE W CARIBBEAN IS ALONG 83W/84W S OF 18N MOVING W 15 KT. ONLY A SLIGHT HINT OF LOW CLOUD CURVATURE IS NOTED ON SATELLITE IMAGERY AS THE WAVE IS BENEATH A BROAD UPPER RIDGE. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS COVER THE NW CARIBBEAN FROM 15N-20N W OF 81W TO OVER THE YUCATAN PENINSULA. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 12N14W 13N25W...DISTORTED BY T.S. DEBBY THEN ALONG 11N33W 9N41W 12N51W 9N62W ACROSS N SOUTH AMERICA TO JUST S OF PANAMA INTO THE E PACIFIC REGION. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 150 NM OF THE AXIS FROM 54W-57W AND WITHIN 90 NM OF THE AXIS FROM 60W-63W. CLUSTERS OF SCATTERED MODERATE CONVECTION ARE FROM 4N-10N E OF 32W TO THE COAST OF AFRICA AND S OF 13N FROM 50W-60W. ...DISCUSSION... GULF OF MEXICO... AN UPPER LOW IS CENTERED IN THE N/CENTRAL ATLC GULF NEAR 27N88W WITH THE UPPER TROUGH EXTENDING FROM THE FLORIDA W COAST TO 94W GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS OVER THE AREA N OF 24N E OF 92W WITH THE BEST CHANCE OF THUNDERSTORMS ALONG THE N GULF COAST. AN UPPER RIDGE EXTENDS ACROSS S MEXICO AND THE BAY OF CAMPECHE INTO THE YUCATAN CHANNEL S OF 24N PROVIDING DIFFLUENCE AND TROPICAL MOISTURE ACROSS MEXICO TO GENERATE SCATTERED MODERATE/ISOLATED STRONG CONVECTION OVER THE BAY OF CAMPECHE S OF 23N W OF 92W TO OVER THE MEXICAN COAST. AN UPPER HIGH ANCHORED OVER CENTRAL TEXAS COVERING THE NW GULF IS GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ALONG THE LOUISIANA AND TEXAS COAST N OF 28N. CARIBBEAN SEA... THE MAIN WEATHER MAKERS IN THE CARIBBEAN TODAY ARE THE TWO TROPICAL WAVES. BROAD UPPER RIDGE EXTENDS ACROSS THE YUCATAN INTO THE W CARIBBEAN W OF 80W WITH A SECOND UPPER RIDGE EXTENDING FROM THE W TROPICAL ATLC ACROSS THE LESSER ANTILLES OVER THE E CARIBBEAN E OF 75W. THIS IS INDUCING A WEAK TROUGH BETWEEN THESES RIDGES WHERE DRY UPPER AIR IS ONLY ABLE TO SUPPORT ISOLATED SHOWERS. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS S OF 10N W OF 78W ACROSS PANAMA AND COSTA RICA DUE TO THE CLOSE PROXIMITY OF THE ITCZ AXIS IN THE E PACIFIC REGION. ATLANTIC OCEAN... AN UPPER HIGH IS IN THE W ATLC OFF THE COAST OF FLORIDA/GEORGIA NEAR 31N79W WITH THE UPPER RIDGE EXTENDING S TO THE N BAHAMA ISLANDS AND A SECOND UPPER RIDGE EXTENDING ENE TO BEYOND BERMUDA. THIS UPPER RIDGE IS GENERATING SCATTERED SHOWERS/ THUNDERSTORMS FROM CUBA ACROSS THE BAHAMAS TO BEYOND 32N W OF 76W WITH SOME ISOLATED SHOWERS MOVING INLAND OVER S FLORIDA. AN UPPER TROUGH IS IN THE CENTRAL ATLC EXTENDING FROM AN UPPER LOW N OF THE REGION SW THROUGH 32N50W TO A WEAK UPPER LOW NEAR 26N60W WITH SCATTERED SHOWERS/ISOLATED THUNDERSTORMS AT THE BASE OF THE UPPER TROUGH FROM 24N-30N BETWEEN 55W-62W. BROAD UPPER HIGH IS ANCHORED IN THE W TROPICAL ATLC NEAR 15N54W AND COVERS THE AREA S OF 24N BETWEEN 40W-70W ENHANCING CONVECTION ASSOCIATED WITH THE ITCZ W OF 50W. A BROAD UPPER RIDGE DOMINATES THE E ATLC E OF 40W IN WHICH T.S. DEBBY IS EMBEDDED. AT THE SURFACE...A RIDGE EXTENDS FROM THE NE ATLC THROUGH 32N38W THROUGH A 1022 MB HIGH IN THE W/CENTRAL ATLC NEAR 29N62W CONTINUING INTO THE GULF OF MEXICO AND WEAKENING AS IT APPROACHES THE TEXAS/MEXICO COAST. AFRICAN DUST SPREADS ACROSS THE TROPICAL ATLC S OF 25N WITH THE HIGHEST CONCENTRATIONS FROM 45W-70W INCLUDING THE E CARIBBEAN AND THE SECOND SURGE FROM 20W-40W IN WHICH T.S. DEBBY IS EMBEDDED. $$ WALLACE