000 AXNT20 KNHC 210003 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT SAT SEP 20 2008 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. ...SPECIAL FEATURES... TROPICAL WAVE IS ALONG 66W S OF 19N MOVING W NEAR 10 KT. A 1009 MB LOW IS EMBEDDED ON THE WAVE AXIS NEAR 16N66W. A LARGE AREA OF SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS E OF THE WAVE AXIS COVERING THE LEEWARD ISLANDS FROM 13N-20N BETWEEN 58W-66W. THIS SYSTEM IS SHOWING SIGNS OF IMPROVED ORGANIZATION. UPPER-LEVEL WINDS ARE EXPECTED TO BECOME MORE FAVORABLE OVER THE NEXT COUPLE DAYS ALLOWING FOR ADDITIONAL DEVELOPMENT TO OCCUR. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 21W/22W S OF 10N MOVING W NEAR 10-15 KT BASED ON THE SATELLITE IMAGERY AND A RECENT PASS OF QUIKSCAT. A MID LEVEL LOW IS ALONG THE WAVE AXIS NEAR 5N. A BROAD AREA OF CLOUDINESS WITH EMBEDDED SHOWERS COVERS THE AREA FROM THE EQUATOR TO 14N BETWEEN 16W-27W. SCATTERED MODERATE CONVECTION IS FROM 8N-11N BETWEEN 21W-24W. TROPICAL WAVE IS ALONG 37W FROM 12N-18N MOVING W 10-15 KT. AN INVERTED-V CURVATURE IS OBSERVED IN THE LOW CLOUD MASS. NO CONVECTION IS NOTED. TROPICAL WAVE IS ALONG 55W S OF 20N MOVING W 10-15 KT. WEAK CYCLONIC TURNING IS NOTED ON THE WAVE AXIS NEAR 18N. SCATTERED SHOWERS ARE FROM 12N-18N BETWEEN 52W-56W. TROPICAL WAVE IS ALONG 80W S OF 19N MOVING W 10-15 KT. WELL DEFINED INVERTED-V CURVATURE IS NOTED. CLUSTERS OF SCATTERED MODERATE CONVECTION IS FROM 12N-15N BETWEEN 79W-83W...AND FROM 15N-19N BETWEEN 76W-80W. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 11N16W 6N30W 7N50W 10N62W. BESIDES THE CONVECTION MENTIONED IN THE TROPICAL WAVE SECTION... SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS INLAND OVER W AFRICA FROM 10N-13N BETWEEN 14W-16W. ISOLATED MODERATE CONVECTION IS FROM 5N-9N BETWEEN 29W-32W. ...DISCUSSION... GULF OF MEXICO... AS OF 2100 UTC A SURFACE TROUGH IS OVER THE W GULF OF MEXICO ALONG 29N94W 25N94W 22N93W. ISOLATED MODERATE CONVECTION IS OVER THE W GULF FROM 20N-27N BETWEEN 89W-97W. IN THE UPPER LEVELS...AN UPPER LEVEL HIGH IS CENTERED OVER S MEXICO NEAR 19N97W PRODUCING W TO NW FLOW OVER THE ENTIRE GULF. CONSIDERABLE UPPER LEVEL MOISTURE COVERS THE ENTIRE GULF. EXPECT CONTINUED CONVECTION OVER THE W GULF FOR THE NEXT 24 HOURS. CARIBBEAN SEA... TWO TROPICAL WAVES ARE OVER THE CARIBBEAN SEA. THE TROPICAL WAVE OVER THE E CARIBBEAN IS TO BE WATCHED AS SLOW DEVELOPMENT COULD OCCUR OVER THE NEXT FEW DAYS. SEE SPECIAL FEATURES ABOVE. THE W CARIBBEAN TROPICAL WAVE CONTINUES TO GENERATE PLENTY OF CONVECTION BUT DEVELOPMENT IS NOT EXPECTED DUE TO UNFAVORABLE UPPER LEVEL WINDS. SEE ABOVE. ELSEWHERE...SCATTERED MODERATE CONVECTION IS INLAND OVER E CUBA BETWEEN 75W-79W. CLUSTERS OF SCATTERED MODERATE CONVECTION IS INLAND OVER CENTRAL AMERICA FROM NICARAGUA TO THE YUCATAN PENINSULA. IN THE UPPER LEVELS... THE UPPER LEVEL HIGH CENTERED OVER S MEXICO IS PRODUCING N FLOW OVER THE W CARIBBEAN W OF 80W. AN UPPER LEVEL TROUGH IS OVER THE LEEWARD ISLANDS PRODUCING W FLOW N OF N OF 16N AND E OF 72W. EXPECT THE TWO TROPICAL WAVES TO BE THE DOMINATE WEATHER PRODUCERS OVER THE NEXT 24 HOURS AS THEY MOVE W. ATLANTIC OCEAN... A SURFACE TROUGH IS OVER THE W ATLANTIC FROM 32N74W TO 29N80W. SCATTERED SHOWERS ARE WITHIN 30 NM OF THE TROUGH AXIS. A 1022 MB HIGH IS OVER THE CENTRAL ATLANTIC NEAR 31N41W PRODUCING FAIR WEATHER. A SURFACE TROUGH IS OVER THE E ATLANTIC FROM 32N19W TO 28N23W. IN THE UPPER LEVELS... A SERIES OF UPPER LEVEL LOWS ARE OVER THE W ATLANTIC AND CENTRAL ATLANTIC AT 27N76W...24N65W... 29N63W...AND 25N48W. UPPER LEVEL HIGHS ARE OVER THE TROPICAL ATLANTIC AT 16N56W AND 17N28W. $$ FORMOSA