000 AXNT20 KNHC 222345 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT TUE SEP 22 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 39W/40W S OF 18N MOVING NW 15 KT. WAVE IS WELL DEFINED IN THE LOW LEVEL CLOUD FIELD WITH SMALL CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION WITHIN 75 NM OF LINE FROM 8N44W TO 13N40W. A LARGE AREA OF SAHARAN DUST IS JUST E OF THE WAVE AXIS. ...ITCZ... THE ITCZ AXIS IS CENTERED ALONG 10N13W 8N21W 8N31W 10N42W 9N48W 11N58W 10N63W. SMALL ISOLATED CLUSTERS OF SCATTERED MODERATE CONVECTION DOT THE AREA WITHIN 120 NM OF THE ITCZ E OF 27W. A BROAD AREA OF MID LEVEL CYCLONIC ROTATION IS JUST INLAND OVER THE COAST OF W AFRICA AND WILL MOVE INTO THE ATLC WATERS LATE TONIGHT INTO WED. ...DISCUSSION... GULF OF MEXICO... A STRONG COLD FRONT IS INLAND OVER TEXAS AND N MEXICO WITH A PRE-FRONTAL SURFACE TROUGH OVER THE NW GULF EXTENDING FROM LAKE CHARLES LOUISIANA ALONG 29N94W TO ACROSS S TEXAS NEAR CORPUS CHRISTI TO LAREDO GENERATING SCATTERED/NUMEROUS SHOWERS WITH SCATTERED THUNDERSTORMS COVERING THE AREA W OF A LINE FROM PENSACOLA FLORIDA TO BROWNSVILLE TEXAS. THE UPPER RIDGE REMAINS ACROSS THE GULF EXTEND FROM AN UPPER HIGH OVER S/CENTRAL MEXICO INTO THE GULF NEAR TAMPICO NE TO FLORIDA N OF TAMPA. AFTERNOON SEABREEZE THUNDERSHOWERS GENERATED INLAND OVER THE FLORIDA PENINSULA ARE MOVING INTO THE GULF WATERS WITHIN 60 NM OF THE COAST FROM EVERGLADES CITY TO JUST N OF TAMPA. POSSIBLE ISOLATED SHOWERS/THUNDERSTORMS ARE MOVING THROUGH THE STRAITS OF FLORIDA S OF THE FLORIDA KEYS TO INLAND OVER CUBA W OF 84W. THE COLD FRONT WILL MOVE INTO THE GULF WATERS LATER TONIGHT AND STALL OVER THE NW GULF LATE WED THROUGH FRI. CARIBBEAN SEA... THE CARIBBEAN IS DOMINATED BY W TO NW UPPER FLOW AND WITH AN ABUNDANCE OF DEEP LAYER MOISTURE IS GENERATING SCATTERED/ NUMEROUS SHOWERS AND SCATTERED THUNDERSTORMS OVER CUBA WITH SCATTERED SHOWERS/THUNDERSTORMS ACROSS THE REMAINDER OF THE N CARIBBEAN N OF 17N FROM 64W-74W AND N OF 15N BETWEEN 74W-83W INCLUDING THE GREATER ANTILLES AND THE VIRGIN ISLANDS. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE ACROSS THE S CARIBBEAN S OF 12N W OF 70W TO INLAND OVER COLOMBIA TO NICARAGUA. ISOLATED SHOWERS DOT THE REMAINDER OF THE CARIBBEAN W OF 75W WHILE THE REMAINDER OF THE E CARIBBEAN REMAINS REMARKABLY CLEAR THIS EVENING. ATLANTIC OCEAN... A WEAK SURFACE TROUGH IS IN THE FAR W ATLC EXTENDING FROM THE NORTH CAROLINA COAST NEAR WILMINGTON THROUGH A 1018 MB LOW NEAR 31N79W TO OFF THE FLORIDA COAST NEAR FORT LAUDERDALE. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE WITHIN 75 NM OF LINE FROM 28N79W TO BEYOND 32N78W. AN UPPER RIDGE IS ANCHORED NEAR THE SURFACE LOW COVERING THE W ATLC N OF 27N FROM 74W TO 81W AND ENHANCING THE ACTIVITY ASSOCIATED WITH THE TROUGH/LOW. AN UPPER TROUGH DIPS S INTO THE W ATLC N OF 25N BETWEEN 57W-70W SUPPORTING A STATIONARY BOUNDARY THAT EXTENDS TO 32N60W AND A SURFACE TROUGH THAT CONTINUES TO 27N65W GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS OVER THE AREA FROM 25N-32N BETWEEN 57W-65W AND FROM 30N-32N BETWEEN 52W-57W. A BROAD E/W UPPER RIDGE DOMINATES THE TROPICAL ATLC ANCHORED NEAR OVER W AFRICA EXTENDING W ALONG 16W/17W TO NEAR 60W. BENEATH THIS UPPER RIDGE EMBEDDED WITHIN SOME DRIER AIR IS A SURFACE TROUGH THAT EXTENDS FROM 24N46W THROUGH A 1010 MB LOW NEAR 15N49W TO 11N50W. THIS UPPER RIDGE IS PROVIDING ENOUGH DIFFLUENCE ALOFT IN SPITE OF THE DRIER AIR TO GENERATE SCATTERED MODERATE/ISOLATED STRONG CONVECTION FROM 20N-22N BETWEEN 45W-48W AND A SECOND AREA FROM 17N-19N BETWEEN 57W-59W. THE LAST VISIBLE SATELLITE IMAGES SHOW AN AREA OF SAHARAN DUST THAT COVERS THE E TROPICAL ATLC N OF 20N AND SE OF A LINE FROM 30N18W TO 16N35W. $$ WALLACE