000 AXNT20 KNHC 301800 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 105 PM EST FRI NOV 30 2012 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...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL ANALYSIS. BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH AXIS EXTENDS FROM THE AFRICAN COAST NEAR 09N13W TO 08N17W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 08N17W TO 04N30W TO 08N45W. A 1011 MB LOW IS EMBEDDED WITHIN THE ITCZ CENTERED NEAR 09N46W. SCATTERED MODERATE CONVECTION IS FROM 02N-09N BETWEEN 08W-28W. ...DISCUSSION... GULF OF MEXICO... WATER VAPOR IMAGERY INDICATES A MIDDLE TO UPPER LEVEL SHORTWAVE TROUGH PROGRESSING EASTWARD ACROSS THE GULF THIS AFTERNOON WITH THE STRONGEST SIGNAL OF LIFT LOCATED OVER THE EASTERN HALF E OF 90W. LOW-LEVEL MOISTURE CONVERGENCE IS MAXIMIZED ALONG A SURFACE TROUGH ANALYZED FROM 24N88W TO 30N87W WHERE ISOLATED SHOWERS AND TSTMS ARE OCCURRING FROM 23N-28N BETWEEN 81W-89W. ELSEWHERE... THE REMAINDER OF THE BASIN IS UNDER THE INFLUENCE OF MOSTLY DRY AIR AND SUBSIDENCE ON W-NW FLOW ALOFT AS SURFACE RIDGING DOMINATES W OF 90W ANCHORED BY A 1031 MB HIGH CENTERED OFF THE CAROLINA COAST IN THE SW NORTH ATLC. THE RIDGE AXIS EXTENDS ACROSS THE SE CONUS TO EASTERN TEXAS WITH PRIMARILY EAST TO SOUTHEAST WINDS. THIS SYNOPTIC WEATHER PATTERN IS FORECAST TO PERSIST THROUGH LATE WEDNESDAY OF NEXT WEEK. CARIBBEAN SEA... AN UPPER LEVEL ANTICYCLONIC CIRCULATION CENTERED OVER THE TROPICAL CENTRAL ATLC NEAR 09N56W INFLUENCES THE ENTIRE CARIBBEAN SEA BASIN THIS AFTERNOON WITH MOSTLY SOUTHWEST TO WESTERLY UPPER LEVEL FLOW. WHILE EASTERN PORTIONS REMAIN DRY ALOFT...ISOLATED LOW-LEVEL LOW-TOPPED SHOWERS CONTINUE PROGRESSING WESTWARD EMBEDDED WITHIN E-NE TRADES IN THE RANGE OF 10 TO 15 KT. THE WESTERN CARIBBEAN IS EXPERIENCING INCREASED CLOUD COVER OVERALL WITH ISOLATED SHOWERS OCCURRING IN THE GULF OF HONDURAS AND SURROUNDING REGION S OF 21N W OF 82W...AND ISOLATED SHOWERS AND TSTMS ACROSS THE SW CARIBBEAN GENERALLY WITHIN 120 NM OF THE CENTRAL AMERICA COAST. THIS CONVECTION IS LIKELY ENHANCED DUE TO CLOSE PROXIMITY OF THE MONSOON TROUGH AXIS EXTENDING ALONG 07N/08N. FINALLY...A SURFACE TROUGH IS ANALYZED MOSTLY INLAND ACROSS PORTIONS OF NORTHERN GUYANA AND NE VENEZUELA FROM 05N57W TO 10N62W. ONSHORE FLOW AND MAXIMIZED LOW-LEVEL MOISTURE CONVERGENCE FOCUSED IN THE VICINITY OF SURFACE TROUGH IS GENERATING SCATTERED SHOWERS AND TSTMS FROM 07N-11N BETWEEN 58W-61W...BRINGING INCREASED CHANCES FOR PRECIPITATION OVER THE NEXT 24 HOURS TO TRINIDAD AND TOBAGO AS WELL AS PORTIONS OF THE EXTREME SE CARIBBEAN. ATLANTIC OCEAN... WESTERLY UPPER LEVEL FLOW DOMINATES OVER THE SW NORTH ATLC AS HIGH PRESSURE CONTROLS MOST OF THE AREA N OF 23N W OF 55W. HOWEVER...A MIDDLE TO UPPER LEVEL SHORTWAVE TROUGH IS ALONG 50W AND SUPPORTS A STATIONARY FRONT ANALYZED FROM 32N52W TO 29N57W THAT BECOMES A SHEAR LINE TO 27N60W TO THE SE BAHAMAS NEAR 23N76W. ISOLATED SHOWERS ARE OCCURRING WITHIN 60 NM EITHER SIDE OF THE FRONT WHILE LOW-LEVEL MOISTURE CONVERGENCE IN THE VICINITY OF THE SHEAR LINE IS GENERATING ISOLATED SHOWERS FROM 20N-27N BETWEEN 60W-80W. EARLIER SCATTEROMETER PASSES SHOWED EVIDENCE OF THE SHEAR LINE WITH STRONGER N-NE WINDS WITHIN 210 NM NORTH OF THE SHEAR LINE AXIS. ALSO A SURFACE TROUGH EXTENDS FROM THE WINDWARD PASSAGE NEAR 20N74W TO 23N72W PROVIDING FOCUS FOR SCATTERED SHOWERS AND ISOLATED TSTMS NORTH OF HISPANIOLA FROM 20N-23N BETWEEN 69W-73W. FARTHER EAST...A MIDDLE TO UPPER LEVEL TROUGH AXIS EXTENDS FROM 30N48W TO 19N36W. THIS UPPER LEVEL FEATURE IS PROVIDING MUCH OF THE CENTRAL ATLC WITH GENERAL SURFACE TROUGHING BETWEEN 35W-55W AND SUPPORTS A 1012 MB LOW CENTERED NEAR 20N49W. A SURFACE TROUGH EXTENDS NORTHWARD FROM THE LOW ALONG 23N48W TO 28N45W. WHILE THIS LOW IS FORECAST TO GRADUALLY DISSIPATE OVER THE NEXT 24 HOURS...GLOBAL MODEL DATA CONTINUES TO SUGGEST THE FORMATION OF A NEW SURFACE LOW TO THE NE NEAR 25N42W. CURRENTLY...SCATTERED SHOWERS AND TSTMS ARE OCCURRING FROM 23N-31N BETWEEN 36W-45W WHICH ARE MORE CLOSELY ASSOCIATED WITH MAXIMUM MIDDLE TO UPPER LEVEL DIFFLUENCE EAST OF THE TROUGH AXIS. OTHERWISE...THE REMAINDER OF THE EASTERN ATLC IS UNDER THE INFLUENCE OF A SURFACE RIDGE ANCHORED BY A 1034 MB HIGH CENTERED NORTH OF THE AZORES NEAR 41N27W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN