000 AXNT20 KNHC 180011 CCA TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 705 PM EST SAT NOV 17 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...TROPICAL WAVES... TROPICAL WAVE IS OVER THE WINDWARD ISLANDS ALONG 61W/62W S OF 16N MOVING W AT 15 KT. CONVECTION ASSOCIATED WITH THE WAVE HAS DIMINISHED DURING THE LAST FEW HOURS. THIS FEATURE IS GENERATING SCATTERED SHOWERS AND ISOLATED TSTMS MAINLY SOUTH OF GUADALOUPE. TROPICAL WAVE IS IN THE CENTRAL CARIBBEAN ALONG 78W S OF 17N MOVING W 10-15 KT. CONVECTION IS MOSTLY W OF THE WAVE AXIS. NELY WINDS AHEAD OF THE WAVE AXIS ARE TRANSPORTING LOW LEVEL MOISTURE ACROSS THE SW CARIBBEAN INTO CENTRAL AMERICA. SCATTERED MODERATE CONVECTION IS WEST OF 80W TO THE COAST OF NICARAGUA AND OVER PARTS OF PANAMA. ...THE ITCZ... THE ITCZ IS PRETTY ACTIVE THIS EVENING. IT AXIS IS CENTERED ALONG 7N12W 5N30W 8N50W 10N61W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 160 NM N OF AXIS BETWEEN 36W-43W... AND WITHIN 100 NM N OF AXIS BETWEEN 45W-52W. SIMILAR CONVECTION IS FOUND FROM 8N-12N BETWEEN 55W-60W. A CLUSTER OF MODERATE TO STRONG CONVECTION IS JUST MOVING OUT OF THE AFRICA COAST THROUGH SIERRA LEONE. DISCUSSION... THE GULF OF MEXICO... THE HIGH PRESSURE THAT BROUGHT IN THE COOL AND DRY AIR MASS IS SHIFTING EAST INTO THE ATLC. AS OF 2100 UTC...A 1022 MB HIGH IS CENTERED OVER THE W ATLC NEAR 31N76W WITH RIDGE ENVELOPING THE STATE OF FLORIDA AND THE GULF. FAIR SKIES ARE OVER THE NE GULF OF MEXICO WITH SCATTERED TO BROKEN COLD AIR STRATOCUMULUS CLOUDS ELSEWHERE. LOW LEVEL RETURN FLOW ON THE WESTERN SIDE OF THE HIGH IS ENHANCING SOME CLOUDINESS WITH EMBEDDED SHOWERS AND TSTMS ALONG THE TEXAS COAST. THIS ACTIVITY IS AHEAD OF A MID/UPPER LEVEL TROUGH MOVING ACROSS TEXAS AND N-CENTRAL MEXICO...AND A SFC TROUGH. SWLY WINDS AHEAD OF THE UPPER TROUGH ARE DRAWING A BAND OF MOISTURE NORTHWARD ACROSS N-CENTRAL MEXICO...TEXAS AND THE SE OF U.S.. THE SFC TROUGH IS FORECAST TO MOVE OVER THE NW GULF WATERS ON SUNDAY. SOUTH WINDS AHEAD OF THE TROUGH WILL SLIGHTLY INCREASE TONIGHT. AN UPPER-LEVEL RIDGE CONTINUES TO DOMINATE MOST OF THE GULF WITH DRY AIR/SUBSIDENCE. THE CARIBBEAN SEA... THE FAST MOVING COLD FRONT THAT SWEPT ACROSS THE GULF AND THE NW CARIBBEAN DURING THE PREVIOUS TWO DAYS IS NOW NEARLY STATIONARY EXTENDING FROM THE EASTERN TIP OF CUBA TO THE COAST OF BELIZE. THE FRONT IS GRADUALLY LOSING ITS IDENTITY ACROSS THE AREA BUT IS STILL GENERATING SOME PATCHES OF LOW/MID CLOUDS OVER BELIZE AND NORTHERN GUATEMALA. NE WINDS OF 15-20 KT ARE NOTED BEHIND THE FRONT. THERE ARE ALSO TWO TROPICAL WAVES MOVING WWD ACROSS THE BASIN. A BROAD UPPER-LEVEL RIDGE DOMINATES THE ENTIRE CARIBBEAN. UPPER DIFFLUENCE BETWEEN THIS RIDGE AN UPPER TROUGH MOVING EWD ACROSS THE W-CENTRAL ATLC CONTINUES TO SUPPORT THE DEVELOPMENT OF SCATTERED SHOWERS AND TSTMS OVER HISPANIOLA AND WITHIN 140 NM NORTH OF THE ABC ISLANDS. AS WAS PREDICTED BY THE COMPUTER MODELS...TRADE WINDS HAVE INCREASE ACROSS THE CENTRAL CARIBBEAN...MAINLY JUST OFFSHORE THE COLOMBIAN COAST. ELY WINDS ARE EXPECTED TO BE IN THE 25 TO 30 KT RANGE TONIGHT THROUGH SUN NIGHT. THE ATLANTIC OCEAN... A COLD FRONT ENTERS THE FORECAST AREA NEAR 31N55W THEN CONTINUES SW TO THE SE BAHAMAS AND THE EASTERN TIP OF CUBA WHERE IT BECOMES NEARLY STATIONARY. POCKETS OF COLD AIR STRATOCUMULUS CLOUDS ARE BEHIND THE FRONT WHILE SCATTERED MODERATE CONVECTION REMAINS WELL AHEAD OF THE FRONT AFFECTING FROM 25N-31N BETWEEN 50W AND THE FRONT IT SELF. ANOTHER COLD FRONT IS OVER THE E ATLANTIC APPROACHING THE MADEIRA/CANARY ISLANDS AND EXTENDS ALONG 31N18W 25N25W 23N40W. A REINFORCING COLD FRONT IS FURTHER NW WITHIN 240 NM OF THE MAIN FRONT WHICH IS GENERATING A CLUSTER OF MODERATE TO STRONG CONVECTION JUST SW OF THE MADEIRA ISLANDS. IN THE UPPER LEVELS...A TROUGH/RIDGE/TROUGH PATTERN DOMINATES THE DISCUSSION AREA. MOSTLY WLY FLOW IS OVER THE TROPICAL ATLANTIC...PARTICULARLY S OF 20N AND E OF 50W. THE UPPER-LEVEL RIDGE THAT DOMINATES THE CARIBBEAN SEA EXTENDS EASTWARD ACROSS THE LEEWARD ISLANDS INTO THE TROPICAL NORTH ATLANTIC. $$ GR