000 AXNT20 KNHC 151805 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT SUN JUL 15 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...TROPICAL WAVES... CENTRAL ATLANTIC TROPICAL WAVE IS TILTED ALONG AXIS 19N32W 3N36W...MOVING WEST 15-20 KT. THIS IS A VERY LARGE AMPLITUDE WAVE WITH VISIBLE SATELLITE IMAGERY INDICATING BROAD TURNING IN THE STRATOCUMULUS FIELD BETWEEN 30W AND 48W. IN ADDITION CIMSS ANALYSES SHOW A LARGE OF AREA OF SAHARAN DUST AHEAD OF AND IN THE WAKE OF THE WAVE AXIS. THIS DUST WAS INHIBITING DEEP CONVECTION WITH THE EXCEPTION OF A SMALL CLUSTER OF SCATTERED MODERATE CONVECTION NEAR THE INTERSECTION OF THE WAVE AXIS AND ITCZ FROM 5N TO 8N BETWEEN 30W AND 35W. STRONGLY TILTED TROPICAL WAVE ALONG 20N55W TO NEAR TRINIDAD WAS MOVING WEST ABOUT 15 KT. SURFACE OBSERVATIONS IN THE WINDWARD ISLANDS CLEARLY SHOW A WINDSHIFT WITH THE PASSAGE OF THE WAVE. THE 1200 UTC SOUNDING FROM TRINIDAD INDICATED AN INCREASE IN LOW LEVEL WINDS AND PW VALUES EXCEEDING 2 INCHES. THE WAVE IS COMING UNDER THE INFLUENCE OF AN UPPER LEVEL TROUGH OVER THE MID ATLANTIC OCEAN WITH DIFLUENT FLOW E OF THE TROUGH AXIS AIDING IN THE DEVELOPMENT OF SCATTERED MODERATE ISOLATED STRONG CONVECTION WITHIN 120-180 NM E OF THE WAVE AXIS. THIS ACTIVITY IS EXPECTED TO PUSH NORTHWESTWARD TOWARD PUERTO RICO BY 24 HOURS. TROPICAL WAVE S OF 19N ALONG 90W WAS ADJUSTED WESTWARD AND HAS NOW MOVED INLAND OVER PORTIONS OF BELIZE...GUATEMALA AND THE YUCATAN PENINSULA. VERY LITTLE IN THE WAY OF THUNDERSTORM ACTIVITY WAS NOTED WITH THE WAVE OVER CENTRAL AMERICA. THE PORTION OF THE WAVE WHICH EXTENDED INTO THE EAST PACIFIC WAS MORE ACTIVITY WITH WELL DEFINED TURNING IN THE LOW CLOUDS NOTED ALONG THE WAVE AXIS NEAR 12N. ...THE ITCZ... AXIS OF THE ITCZ IS ALONG 11N16W 10N21W 12N34W 4N44W 4N52W. OTHER THAN THE CONVECTION DESCRIBED IN ASSOCIATION WITH THE TILTED WAVE ALONG 19N32W 3N36W...ONLY ISOLATED MODERATE THUNDERSTORMS NOTED ELSEWHERE WITHIN 90-120 NM OF THE WAVE AXIS BETWEEN AFRICA AND 52W. ...DISCUSSION... THE GULF OF MEXICO... EXTENSION OF AN ATLANTIC SURFACE RIDGE IS FROM SOUTH FLORIDA THROUGH 26N90W TO THE NORTHERN COAST OF MEXICO NEAR MONTERREY. HIGHLY AMPLIFIED FLOW EXISTS OVER THE CONUS WITH THE AXIS OF A SHARP UPPER LEVEL TROUGH EXTENDING FROM THE RED RIVER VALLEY SOUTHWARD ALONG THE TEXAS COAST TO NEAR BROWNSVILLE. THE ASSOCIATED SOUTHWESTERLY UPPER LEVEL FLOW AND UPPER DIFFLUENCE WAS INCREASING IN AREA OVER THE GULF OF MEXICO. AS A RESULT SCATTRED MODERATE TO STRONG THUNDERSTORMS WERE ERUPTING ALONG A SURFACE TROUGH WHICH EXTENDED FROM THE S-CENTRAL COAST OF LOUISIANA TO THE CENTRAL TEXAS COAST. THE SMALL CYCLONIC CIRCULATION NEAR 25N86W YESTERDAY WAS BECOMING ABSORBED INTO THE LARGER AREA OF SOUTHWESTERLY FLOW ALOFT AND BECOMING LESS DISTINCT NEAR 27N84W. NARROW RIDGE AXIS BETWEEN ANTICYCLONES OVER BELIZE AND THE W ATLANTIC WAS OVER SOUTH FLORIDA AND THE FLORIDA STRAITS. THE CARIBBEAN SEA... A MID TO UPPER LEVEL ANTICYCLONE OVER BELIZE WAS INFLUENCING LESS AND LESS OF THE CARIBBEAN AS THE FEATURE MOVED WWD OVER CENTRAL AMERICA. THIS ANTICYCLONE WAS CONNECTED TO THE ANTICYCLONE OVER THE WESTERN ATLANTIC OCEAN. THE BASE OF A MID TO UPPER LEVEL TROUGH WAS SPREADING WESTWARD OVER THE CARIBBEAN AND ENTERED THE BASIN OVER HAITI AND EXTENDED SOUTHWARD TO 12N79W WITH A DEVELOPING CYCLONIC CIRCULATION NOTED NEAR 15N77W. A BROAD SWATH OF AMPLIFYING SOUTHWESTERLY FLOW AT THE MID AND UPPER LEVELS COVERS THE AREA SOUTHEAST OF THE UPPER TROUGH AND 73W. THIS DIFLUENT FLOW REGIME WAS ENHANCING SCATTERED MODERATE ISOLATED STRONG CONVECTION ALONG THE TILTED TROPICAL WAVE ENTERING THE FAR EASTERN CARIBBEAN. ELSEWHERE ONLY LOW TOPPED SHOWERS AND ISOLATED THUNDERSTORMS WERE NOTED OVER THE CARIBBEAN. THE ATLANTIC OCEAN... A PERSISTENT POSITIVELY TILTED MID TO UPPER LEVEL TROUGH EXTENDS FROM A MIDDLE TO UPPER LEVEL CYCLONIC CIRCULATION CENTER NEAR 30N56W THROUGH 25N64W TO A SECOND CYCLONIC CENTER JUST NORTH OF HISPANIOLA NEAR 21N69W THEN CONTINUES SOUTHWESTWARD TO HAITI. WIDELY SCATTERED MODERATE CONVECTION IS NOTED IN ASSOCIATION WITH THE SECOND CYCLONIC CIRCULATION. AN EXPANDING ANTICYCLONE WAS NOTED OVER THE TROPICAL ATLANTIC NEAR 17N49W WITH A SMALLER ANTICYCLONE NEAR 22N35W. BOTH FEATURES DOMINATED THE AREA BETWEEN 25W AND 55W. A SHEARED EASTERN ATLANTIC MIDDLE TO UPPER LEVEL TROUGH EXTENDS FROM 32N10W TO 27N27W 27N35W. SURFACE ANTICYCLONIC FLOW IS NORTH OF 20N BETWEEN AFRICA AND 80W. $$ COBB