000 AXNT20 KNHC 211749 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 105 PM EST SAT NOV 21 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...ITCZ... THE ITCZ AXIS IS CENTERED ALONG 7N12W 5N26W 6N46W 7N50W 7N62W. WIDELY SCATTERED MODERATE CONVECTION IS FROM 4N-8N BETWEEN 9W-20W. SIMILAR CONVECTION IS FROM 3N-8N BETWEEN 25W-42W. A SURFACE TROUGH EMBEDDED WITHIN THE ITCZ AXIS IS ANALYZED FROM 14N44W TO 6N49W. SCATTERED SHOWERS AND ISOLATED MODERATE CONVECTION IS FROM 5N-14N BETWEEN 42W-50W. ...DISCUSSION... GULF OF MEXICO... AN UPPER LEVEL SHORTWAVE TROUGH IS PROGRESSING EASTWARD OVER NE TEXAS AND WESTERN LOUISIANA AND SUPPORTS A 1009 MB LOW CENTERED IN THE NW GULF WATERS NEAR 28N94W. A COLD FRONT EXTENDS S FROM THE LOW ALONG 28N93W 25N93W TO NEAR TUXPAN MEXICO. A WARM FRONT ALSO EXTENDS EAST FROM THE LOW TO 26N87W. LOW-LEVEL CONVERGENCE NEAR THE FRONTS ALONG WITH A ZONE OF MIDDLE TO UPPER LEVEL DIFFLUENCE LOCATED EAST OF THE UPPER LEVEL TROUGH AXIS IS GENERATING NUMEROUS SHOWERS AND SCATTERED TSTMS N OF 25N BETWEEN 88W-92W...AND WITHIN 60 NM E OF THE COLD FRONT S OF 25N. THE LOW IS FORECAST TO MOVE E-NE OVER THE NEXT 24 HOURS AND LOCATE OVER THE NE GULF COAST NEAR MOBILE ALABAMA PROVIDING CONTINUED PRECIPITATION AND CONVECTION ALONG THE FRONTAL BOUNDARIES TO INLAND ACROSS THE GULF COAST E OF 90W. PRIMARILY W-SW UPPER LEVEL FLOW IS NOTED ON WATER VAPOR IMAGERY ACROSS THE REMAINDER OF THE GULF WITH A SURFACE RIDGE EXTENDING FROM THE MID-ATLC STATES ALONG THE EASTERN U.S. SEABOARD TO THE FLORIDA PENINSULA PROVIDING GENERALLY FAIR SKIES OVER FLORIDA AND THE FAR EASTERN GULF THIS AFTERNOON. CARIBBEAN SEA... AN UPPER LEVEL RIDGE WITH AXIS ALONG 75W EXTENDING FROM NORTHERN COLOMBIA TO CUBA AND HISPANIOLA COVERS A MAJORITY OF THE CARIBBEAN. STRONG SUBSIDENCE IS NOTED ON WATER VAPOR IMAGERY WITH ONLY A FEW ISOLATED SHOWERS OCCURRING FROM 15N-18N BETWEEN 81W-85W DRIVEN PRIMARILY BY SURFACE WIND CONVERGENCE IN THE LOW LEVELS. ALSO...SCATTERED SHOWERS AND ISOLATED TSTMS ARE PRESENT OVER THE SW CARIBBEAN...PANAMA...AND COSTA RICA S OF 11N. DRY W-NW FLOW ALOFT IS OVER PUERTO RICO AND THE LESSER ANTILLES... WITH ISOLATED SHOWERS OCCURRING N OF 17N BETWEEN 68W-72W AS WELL AS OVER THE SE CARIBBEAN S OF 14N E OF 66W BEING USHERED IN ON MODERATE TO FRESH TRADE WINDS. ATLANTIC OCEAN... A SURFACE RIDGE EXTENDS FROM THE MID-ATLC STATES ALONG THE U.S. EASTERN SEABOARD AND ACROSS THE FAR W ATLC WATER AND FLORIDA PENINSULA. MULTILAYERED CLOUDINESS AND ISOLATED SHOWERS SURROUND THE SOUTHERN EXTENT OF A STATIONARY FRONT EXTENDING FROM NORTH OF THE AREA TO 31N76W. PRECIPITATION CONTINUES TO BE ENHANCED N OF 30N W OF 72W BY AN UPPER LEVEL DIFFLUENT ENVIRONMENT EAST OF THE APPROACHING SHORTWAVE TROUGH CURRENTLY OVER THE SOUTHERN PLAINS AND TROUGHING CURRENTLY OVER EASTERN CANADA. FARTHER TO THE SE...A SURFACE TROUGH EXTENDS FROM 32N70W ALONG 27N73W TO 24N77W. LOW-LEVEL CONVERGENCE NEAR THE SURFACE TROUGH IS GENERATING ISOLATED SHOWERS WITHIN 90 NM EITHER SIDE OF THE BOUNDARY...INCLUDING THE CENTRAL BAHAMAS. ANOTHER SURFACE TROUGH IS ANALYZED FROM 23N63W TO EASTERN HISPANIOLA NEAR 18N69W. SCATTERED SHOWERS ARE FROM 20N-23N BETWEEN 59W-70W IN THE VICINITY OF THE SURFACE TROUGH. A PAIR OF UPPER LEVEL SHORTWAVE TROUGHS ARE EMBEDDED WITHIN MAINLY ZONAL WESTERLY FLOW ACROSS THE REMAINDER OF THE ATLC N OF 20N. THE FIRST SHORTWAVE AXIS IS LOCATED ALONG 63W N OF 30N AND SUPPORTS A 1013 MB LOW CENTERED NEAR 33N68W. A CONVERGENT FRONTAL BOUNDARY EXTENDS E-SE FROM THE LOW ALONG 32N62W 28N57W TO 27N53W. SCATTERED SHOWERS AND ISOLATED TSTMS ARE WITHIN 120 NM N OF THE BOUNDARY... REMAINING LARGELY NORTH OF THE DISCUSSION AREA. THE SECOND UPPER LEVEL SHORTWAVE IS ALONG 47W N OF 22N AND SUPPORTS A 1017 MB LOW CENTERED NEAR 26N50W. THIS LOW IS NEAR THE TAIL END OF A FRONTAL BOUNDARY THAT ENTERS THE DISCUSSION AREA TO THE EAST NEAR 32N19W AS A COLD FRONT THAT EXTENDS TO 27N28W AND THEN AS A STATIONARY FRONT ALONG 27N/28N TO NORTH OF THE AFOREMENTIONED LOW NEAR 27N50W. SCATTERED SHOWERS AND ISOLATED TSTMS SURROUND THE LOW COVERING THE AREA FROM 22N-32N BETWEEN 42W-52W. SCATTERED SHOWERS ARE ALSO OCCURRING WITHIN 90 NM TO 120 NM EITHER SIDE OF THE FRONT. $$ HUFFMAN