000 AXNT20 KNHC 231802 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT MON JUL 23 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 1745 UTC. ...TROPICAL WAVES... A LARGE ATLC OCEAN TROPICAL WAVE IS ALONG 24N38W 7N36W MOVING QUICKLY W NEAR 25 KT. THE WAVE EXHIBITS A VERY LARGE INVERTED V SHAPE AND MAY EXTEND EVEN FURTHER N BASED ON THIS AFTERNOONS VISIBLE IMAGERY. A DENSE LAYER OF SAHARAN DUST IS EVIDENT ON BOTH SIDES OF THE AXIS. DEEP CONVECTION IS MINIMAL. E CARIBBEAN TROPICAL WAVE IS ALONG 70W S OF 19N MOVING W 15-20 KT. WAVE PASSAGE WAS EVIDENT IN THE SAN JUAN SOUNDING DATA YESTERDAY EVENING. ASSOCIATED SCATTERED SHOWERS/ISOLATED TSTMS ARE FROM 14N-21N BETWEEN 64W-75W. W CARIBBEAN TROPICAL WAVE IS ALONG 86W/87W S OF 20N MOVING W NEAR 15 KT. SOME SLIGHT LOW TO MID LEVEL CYCLONIC TURNING NOTED IN SATELLITE IMAGERY. SCATTERED SHOWERS/ISOLATED TSTMS ARE OVER THE GULF OF HONDURAS...BELIZE..AND THE ERN YUCATAN PENINSULA FROM 16N-22N BETWEEN 84W-89W. SIMILAR ACTIVITY IS OVER ERN NICARAGUA. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 14N16W 13N25W 11N35W 8N50W 6N57W. SCATTERED MODERATE CONVECTION IS S OF THE AXIS FROM 8N-11N BETWEEN 16W-33W. ISOLATED MODERATE IS WITHIN 90NM EITHER SIDE OF THE AXIS BETWEEN 46W-51W. ...DISCUSSION... GULF OF MEXICO... COMPLEX FRONTAL PATTERN CONTINUES TO PRODUCE MESSY WEATHER OVER THE ERN GULF THIS AFTERNOON. THE MOST CONCENTRATED CLUSTER OF MODERATE CONVECTION IS NEAR THE FLORIDA PANHANDLE N OF 28N E OF 89W. SCATTERED SHOWERS/ISOLATED TSTMS DOT THE REMAINDER OF THE GULF E OF 89W. AS OF 23/1500 UTC A 1014 MB LOW WAS JUST OFF THE COAST OF SE LOUISIANA NEAR 29N88W. THIS LOW HAS A DYING STATIONARY FRONT EXTENDING ESE AND ENTERING CENTRAL FLORIDA NEAR 28N83W OR JUST N OF CLEARWATER FL. A COLD FRONT EXTENDS SW FROM THE LOW TO 26N92W AND THEN NW TO THE TEXAS COAST NEAR FREEPORT TEXAS. IT HAS REMAINED A CHALLENGE TO ANALYZE THE FRONTAL SYSTEM THIS MORNING GIVEN THE MANY CONVECTIVE BOUNDARIES EVIDENT AND THE FRONT LOSING MUCH OF ITS THERMAL CONTRAST. HOWEVER...DEWPOINTS REMAIN IN THE LOW TO MID 70S S OF THE BOUNDARY AND MOSTLY IN THE 60S TO THE N. THE UPPER SUPPORT CONSISTS OF AN ELONGATED UPPER TROUGH EXTENDING SW FROM MOBILE TO THE WRN BAY OF CAMPECHE NEAR 20N97W. THIS IS ALSO SUPPORTING ISOLATED TSTMS JUST OFF THE MEXICAN COAST FROM 19N-23N W OF 93W. RIDGING WILL GRADUALLY FILL BUILD OVER THE GULF FROM THE ATLC THROUGH MIDWEEK AS THE FRONT CONTINUES TO SLOWLY WEAKEN AND LIFT N. CARIBBEAN SEA... THE TROPICAL WAVES IN THE CARIBBEAN ARE RESPONSIBLE FOR MOST OF THE WEATHER IN THE CARIBBEAN THIS AFTERNOON AS DESCRIBED ABOVE. OTHERWISE LIGHT TO MODERATE TRADES DOMINATE SW OF THE ATLC HIGH. THE EXCEPTION IS LIGHTER SE FLOW IN THE FAR NW PORTION. TRADES INCREASE SLIGHTLY...MAINLY FOR THE CENTRAL CARIB...THROUGH MIDWEEK. ALOFT...AN UPPER HIGH IN THE NW CARIBBEAN NEAR 18N81W DOMINATES. THIS IS SPREADING DEBRIS MOISTURE ASSOCIATED WITH THE CONVECTION FROM THE WAVE S OF HISPANIOLA TO THE SW. ATLANTIC OCEAN... THE SAME DYING STATIONARY FRONT DESCRIBED IN THE GULF SECTION EXITS CENTRAL FLORIDA NEAR COCOA BEACH AND CONTINUES NE TO 31N75W. SCATTERED SHOWERS/ISOLATED TSTMS ARE IN THE UNSTABLE ENVIRONMENT WITHIN 200 NM AHEAD OF THE FRONT. A SEPARATE AREA OF SCATTERED MODERATE CONVECTION IS FURTHER E...N OF 27N BETWEEN 64W-71W. LOW CLOUD MOTIONS SHOW SOME LOW LEVEL CONFLUENCE IN THIS VICINITY...THOUGH THE CONVECTION IS ALSO BEING SUPPORTED BY DIFFLUENCE ALOFT BETWEEN THE LARGE UPPER LOW OVER THE ERN U.S. AND RIDGING EXTENDING NE FROM THE CARIBBEAN. ANOTHER UPPER LOW IS NEAR 24N52W BUT IS NOT GENERATING ANY SIGNIFICANT WEATHER. THE REMAINDER OF DISCUSSION AREA N OF 15N E OF 60W IS WIDELY DOMINATED BY FAIR WEATHER AND MODERATE TO FRESH TRADES S OF A 1031 MB HIGH NEAR 37N45W. $$ WILLIS