000 AXNT20 KNHC 100532 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT MON AUG 10 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0445 UTC. ...SPECIAL FEATURES... TROPICAL WAVE IS ALONG 23W FROM 10N TO 19N WITH A 1008 MB LOW ALONG THE WAVE NEAR 14N DRIFTING WESTWARD. LATEST INFRARED SATELLITE IMAGERY INDICATES A WELL DEFINED LOW/MID LEVEL CYCLONIC CIRCULATION WITH A CLUSTERS OF SCATTERED MODERATE/ ISOLATED STRONG CONVECTION FLARING UP NEAR AND TO THE SW OF THE LOW LEVEL CIRCULATION FROM 11N TO OVER THE THE SOUTHERN MOST CAPE VERDE ISLANDS BETWEEN 22W-27W. CONDITIONS APPEAR FAVORABLE FOR DEVELOPMENT OF THIS SYSTEM AND IT COULD BECOME A TROPICAL DEPRESSION DURING THE NEXT DAY OR TWO. ASSOCIATED SHOWERS AND THUNDERSTORMS WITH LOCALLY GUSTY WINDS COULD AFFECT PORTIONS OF THE CAPE VERDE ISLANDS DURING THE NEXT 24 HOURS. SEE THE TROPICAL WEATHER OUTLOOK UNDER AWIPS/WMO HEADERS MIATWOAT/ABNT20 KNHC FOR ADDITIONAL DETAILS. ...TROPICAL WAVES... TROPICAL WAVE IS TILTED NW TO SE FROM 17N46W TO 8N39W MOVING W 10-15 KT. THE AXIS OF THE WAVE IS ORIENTED WITHIN A MOISTURE MAXIMUM OBSERVED IN TOTAL PRECIPITABLE WATER IMAGERY AND WELL DEFINED CURVATURE IN THE LOW CLOUDS. SMALL CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE WITHIN 60 OF LINE FROM 14N38W TO 15N48W. TROPICAL WAVE IS ALONG 56W/57W S OF 18N MOVING W 10-15 KT. WAVE IS LOCATED ALONG A MOISTURE MAXIMUM OBSERVED IN THE TOTAL PRECIPITABLE WATER IMAGERY AND LOW LEVEL CYCLONIC CIRCULATION IN THE LOW CLOUDS ALONG THE WAVE AXIS NEAR 13N. SCATTERED SHOWERS ARE FROM 14N-16N BETWEEN 55W-59W. TROPICAL WAVE IS ALONG 67W/68W S OF 16N MOVING W 15-20 KT. WAVE IS EMBEDDED WITHIN AN AREA OF MODERATE ELY TRADES OVER THE E CARIBBEAN AND COINCIDES WITH A LOW AMPLITUDE MOISTURE MAXIMUM OBSERVED IN THE TOTAL PRECIPITABLE WATER IMAGERY. HOWEVER...DUE TO THE DRY STABLE CONDITIONS THERE IS NO ASSOCIATED SHOWER ACTIVITY OR CONVECTION. TROPICAL WAVE IS ALONG 88W S OF 17N MOVING W 10-15 KT. THIS WAVE IS MOVING OUT OF THE CARIBBEAN AND OVER CENTRAL AMERICA AND IN THE E PACIFIC REGION WITH NO SIGNIFICANT SHOWERS/CONVECTION IN THE AREA. ...ITCZ... THE ITCZ AXIS IS CENTERED ALONG 11N26W 7N43W 13N56W 11N65W. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE INLAND AND WITHIN 120 NM ALONG THE COAST OF W AFRICA FROM 6N-9N AND WITHIN 120 NM ALONG THE ITCZ FROM 41W-49W. ...DISCUSSION... GULF OF MEXICO... LARGE UPPER RIDGE ANCHORED OVER SOUTH CAROLINA EXTENDS OVER THE E GULF N OF 24N E OF 88W WITH A SURGE OF DRY AIR ALOFT SWEEPING ACROSS N FLORIDA AND THE NE GULF N OF 28N CAPPING THUNDERSTORM DEVELOPMENT OVER FLORIDA AND PUSHING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS OVER THE E GULF FROM 24N-27N BETWEEN 83W-85W WITH ISOLATED SHOWERS DOTTING THE AREA FROM 22N-28N BETWEEN 82W-90W. AN UPPER RIDGE IS ANCHORED OVER S MEXICO NEAR 18N96W COVERING THE W GULF DRAWING UPPER LEVEL MOISTURE FROM THE TROPICS ACROSS MEXICO AND OVER THE FAR W GULF. UPPER LEVEL DIFFLUENCE COUPLED WITH LOW LEVEL CONVERGENCE IS GENERATING ISOLATED SHOWERS/ THUNDERSTORMS OVER THE BAY OF CAMPECHE S OF 21N BETWEEN 92W-97W. CARIBBEAN SEA... THE W CARIBBEAN IS DOMINATED BY AN UPPER LOW CENTERED OVER CAYMAN ISLANDS GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS N OF 21N TO OVER W CUBA BETWEEN 82W-85W. THE E CARIBBEAN IS DOMINATED BY AN UPPER HIGH S OF PUERTO RICO NEAR 16N67W. VERY DRY AIR ALOFT IS NOTED OVER MUCH OF THE REGION WITH THE EXCEPTION BEING ACROSS THE FAR S CARIBBEAN. THIS MOIST AIR COUPLED WITH THE ITCZ AXIS THAT EXTENDS ACROSS THE ABC ISLANDS THEN THE N PORTION OF VENEZUELA AND COLOMBIA CROSSING PANAMA INTO THE E PACIFIC REGION IS GENERATING SCATTERED SHOWERS/ THUNDERSTORMS S OF 13N W OF 73W TO OVER THE AREA FROM COLOMBIA TO NICARAGUA WITH ISOLATED SHOWERS OVER THE WINDWARD ISLANDS S OF 14N E OF 65W. A SMALL AREA OF UPPER DIFFLUENCE IS OVER HAITI AND THE ADJACENT COASTAL WATERS GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS FROM 18N-20N BETWEEN 72W-76W. ATLANTIC OCEAN... THE UPPER RIDGE THAT COVERS THE E GULF OF MEXICO COVERS THE W ATLC N OF 24N W OF 69W WITH DRY AIR ALOFT SUPPRESSING ANY SHOWERS/THUNDERSTORMS. HOWEVER...A NARROW UPPER TROUGH EXTENDS FROM 27N62W ACROSS E CUBA TO AN UPPER LOW OVER THE CAYMAN ISLANDS. A NARROW BAND OF UPPER LEVEL DIFFLUENCE BETWEEN THE UPPER RIDGE AND TROUGH IS GENERATING SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS WITHIN 90/120 NM S OF A SURFACE TROUGH THAT EXTENDS FROM A COLD FRONT N OF THE REGION THROUGH 32N59W TO 28N73W. A SECOND SURFACE TROUGH IS TO THE E AND EXTENDS FROM 28N55W TO 23N59W AND WILL CONTINUE WEAKENING AS THE UPPER LEVEL SUPPORT HAS NOW MOVED N OF THE REGION. HIGH PRESSURE HAS BEGUN TO DOMINATE THE ATLC BASIN WITH A SURFACE RIDGE OVER THE W ATLC AND GULF OF MEXICO ANCHORED BY A 1021 MB HIGH OVER SW GEORGIA AND A SECOND SURFACE RIDGE OVER THE E ATLC ANCHORED BY A 1027 MB HIGH JUST W OF THE AZORES. THE REMAINDER OF THE ATLC REMAINS TRANQUIL TONIGHT WITH A BROAD AREA OF SAHARAN DUST COVERING MOST OF THE AREA E OF 50W. $$ WALLACE