000 AXNT20 KNHC 291741 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 105 PM EST THU NOV 29 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 INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM THE AFRICAN COAST NEAR 09N13W TO 05N24W TO 09N42W TO 07N50W TO 07N59W. A 1011 MB LOW IS EMBEDDED WITHIN THE ITCZ CENTERED NEAR 08N46W. SCATTERED MODERATE CONVECTION IS FROM 06N-17N BETWEEN 23W-40W AND FOCUSES AROUND A SURFACE TROUGH ANALYZED FROM 12N32W TO 08N38W. THIS LARGE AREA OF CONVECTION IS LARGELY ENHANCED DUE TO A MIDDLE TO UPPER LEVEL LOW CENTERED NEAR 22N44W. ...DISCUSSION... GULF OF MEXICO... WATER VAPOR IMAGERY INDICATES VERY SUBTLE MID-LEVEL TROUGHING PROGRESSING ACROSS THE GULF THIS AFTERNOON WITH THE STRONGEST SIGNAL OF LIFT LOCATED OVER NORTHWEST PORTIONS. LOW-LEVEL MOISTURE CONVERGENCE IS MAXIMIZED ALONG A LINE FROM 24N92W TO 28N95W WHERE POSSIBLE ISOLATED SHOWERS ARE OCCURRING WITHIN 75 NM EITHER SIDE OF THE LINE. TO THE SW...A SURFACE TROUGH EXTENDS FROM 19N94W TO 24N97W AND CONTINUES TO PROVIDE FOCUS FOR ISOLATED SHOWERS S OF 25N W OF 94W. THE REMAINDER OF THE BASIN IS UNDER THE INFLUENCE OF MOSTLY DRY AIR AND SUBSIDENCE ALOFT WITH SURFACE RIDGING DOMINATING E OF 90W ANCHORED BY A 1032 MB HIGH CENTERED OVER THE DELMARVA AND CAROLINAS. CARIBBEAN SEA... AN UPPER LEVEL ANTICYCLONIC CIRCULATION CENTERED OVER NORTHWESTERN VENEZUELA NEAR 11N69W INFLUENCES THE ENTIRE CARIBBEAN SEA BASIN THIS AFTERNOON WITH MOSTLY SOUTH TO SOUTHWESTERLY UPPER LEVEL FLOW W OF 70W AND WEST TO NORTHWESTERLY UPPER LEVEL FLOW E OF 70W. WHILE EASTERN PORTIONS REMAIN DRY AND UNDER RELATIVELY TRANQUIL CONDITIONS AT THE SURFACE...THE WESTERN CARIBBEAN IS EXPERIENCING INCREASED CLOUD COVER AND ISOLATED SHOWERS AND TSTMS IN TWO AREAS ALONG THE CENTRAL AMERICA COAST. A SURFACE TROUGH SNAKES ALONG 12N83W TO 15N84W TO 17N87W TO 21N88W WHERE MAXIMUM LOW-LEVEL MOISTURE CONVERGENCE IS LOCATED. ISOLATED SHOWERS AND TSTMS ARE OCCURRING OVER THE NW CARIBBEAN FROM 15N-22N BETWEEN 82W-88W IN VICINITY OF THE SURFACE TROUGH AND OVER THE SW CARIBBEAN S OF 16N BETWEEN 75W-84W...INCLUDING INLAND PORTIONS OF PANAMA AND COSTA RICA. ATLANTIC OCEAN... A MIDDLE TO UPPER LEVEL TROUGH AXIS EXTENDS ALONG 58W AND DIPS SOUTHWARD TO A BASE NEAR 32N WHICH SUPPORTS A COLD FRONT ANALYZED INTO THE DISCUSSION AREA ALONG 32N60W TO 26N70W WHERE IT BECOMES STATIONARY TO THE SE BAHAMAS NEAR 23N76W. WIDELY SCATTERED SHOWERS AND ISOLATED TSTMS ARE OCCURRING N OF 29N BETWEEN 54W AND THE FRONT...AND WITHIN 90 NM EITHER SIDE OF THE FRONT S OF 29N. A PRE-FRONTAL SURFACE TROUGH EXTENDS FROM THE NORTHERN COAST OF HISPANIOLA NEAR 20N71W TO 25N69W AND IS PROVIDING FOCUS FOR ISOLATED SHOWERS AND TSTMS FROM 20N-25N BETWEEN 67W-73W. OTHERWISE THE REMAINDER OF THE SW NORTH ATLC WEST OF THE COLD FRONT IS UNDER THE INFLUENCE OF A SURFACE RIDGING ANCHORED BY A 1032 MB HIGH CENTERED OVER THE DELMARVA AND CAROLINAS THIS AFTERNOON. FARTHER EAST OVER PORTIONS OF THE CENTRAL AND EASTERN ATLC...SURFACE RIDGING ALSO DOMINATES ANCHORED BY A 1038 MB HIGH CENTERED NORTH OF THE AZORES NEAR 44N29W. LOCATED WITHIN THE SOUTHERN PERIPHERY OF THE RIDGING...A MIDDLE TO UPPER LEVEL LOW IS CENTERED NEAR 22N44W AND IS PROVIDING AMPLE DIFFLUENCE TO GENERATE SCATTERED SHOWERS AND TSTMS FROM 20N-31N BETWEEN 40W-47W. A SURFACE TROUGH REMAINS IN THE VICINITY OF THIS CONVECTION FROM 19N-27N ALONG 47W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN