000 AXNT20 KNHC 271149 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 705 AM EST SUN NOV 27 2011 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1115 UTC. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 09N13W TO 06N20W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 06N20W TO 05N37W TO 03N51W. ISOLATED MODERATE CONVECTION IS FROM 03N-10N BETWEEN 19W-35W...AND FROM 02N-07N BETWEEN 35W-44W. ...DISCUSSION... GULF OF MEXICO... AN UPPER LEVEL RIDGE INFLUENCES THE GULF BASIN WITH AXIS EXTENDING FROM WESTERN CUBA NORTHWARD ALONG 82W AND THE EASTERN U.S. SEABOARD TO THE MID-ATLC REGION. THIS UPPER LEVEL RIDGE CONTINUES TO BE LOCATED BETWEEN TWO UPPER LEVEL TROUGHS... ONE LOCATED OVER THE SW NORTH ATLC BETWEEN 55W-75W...AND THE OTHER APPROACHING THE GULF FROM THE WEST CURRENTLY NOTED ON WATER VAPOR IMAGERY ACROSS THE SOUTHERN PLAINS AND NORTHERN MEXICO. WHILE THE UPPER LEVEL RIDGE SHIFTS GRADUALLY EASTWARD OVER THE NEXT 24 HOURS...IT CONTINUES TO SUPPORT SURFACE RIDGING OVER THE EASTERN GULF AND FLORIDA PENINSULA E OF 85W ANCHORED BY A 1026 MB HIGH CENTERED OFF THE NORTH CAROLINA COAST NEAR 35N71W. OVER THE WESTERN GULF...THE UPPER LEVEL TROUGHING SUPPORTS A COLD FRONT EXTENDING FROM VERMILION BAY LOUISIANA S-SW TO SOUTH OF TAMPICO MEXICO NEAR 22N98W. STRONG N-NW GALE FORCE WINDS ARE OCCURRING BEHIND THE FRONT WITH SCATTERED SHOWERS AND A FEW ISOLATED TSTMS OCCURRING WITHIN 120 NM EITHER SIDE OF THE FRONT. AN AREA OF SCATTERED SHOWERS IS ALSO LOCATED EAST OF THE FRONT EMBEDDED WITHIN STRONG S-SE FLOW OCCURRING N OF 24N W OF 85W. THE COLD FRONT IS FORECAST TO MOVE EASTWARD ACROSS THE GULF THROUGH SUNDAY AND MOVE ACROSS THE FLORIDA PENINSULA ON MONDAY. CARIBBEAN SEA... WATER VAPOR IMAGERY INDICATES DRY AND STABLE CONDITIONS UNDER W-SW FLOW ALOFT IS OVER THE NW CARIBBEAN NW OF A LINE FROM 11N81W TO 19N71W. THIS AREA IS LOCATED ON THE SOUTHWESTERN PERIPHERY OF A SW NORTH ATLC HIGH PRESSURE WITH NE TO E WINDS IN THE RANGE OF 10 TO 20 KT. LOW-LEVEL CONVERGENCE IS MAXIMIZED IN THE GULF OF HONDURAS WITH ISOLATED SHOWERS OCCURRING S OF 20N W OF 86W. FARTHER EAST...AN SW NORTH ATLC UPPER LEVEL TROUGH DIPS SOUTHWARD TO A BASE NEAR 20N74W AND CONTINUES TO PROVIDE THE REMAINDER OF THE BASIN WITH MOIST SOUTHWESTERLY FLOW ALOFT. SCATTERED SHOWERS AND TSTMS ARE OCCURRING OVER THE SW CARIBBEAN IN THE VICINITY OF THE MONSOON TROUGH...ANALYZED ALONG 10N...S OF 14N BETWEEN 68W-80W. ELSEWHERE E OF 73W...WIDELY SCATTERED SHOWERS AND ISOLATED TSTMS ARE OCCURRING UNDER WEAK UPPER LEVEL DIFFLUENCE AND LOW-LEVEL CONVERGENCE DUE TO A SURFACE TROUGH ANALYZED OVER THE EASTERN CARIBBEAN FROM 12N65W TO 20N64W. THIS MORNING...THE MORE INTENSE CONVECTION IS LOCATED EAST OF THE SURFACE TROUGH WITH SCATTERED SHOWERS AND TSTMS OCCURRING FROM 13N-19N BETWEEN 59W-64W. ATLANTIC OCEAN... AN UPPER LEVEL TROUGH IS NOTED ON WATER VAPOR IMAGERY ACROSS THE W ATLC WITH AXIS FROM 33N53W TO 28N64W TO A BASE NEAR 20N74W. THE TROUGHING SUPPORTS A DISSIPATING STATIONARY FRONT EXTENDING FROM 32N55W SW TO 25N59W. WITH UPPER LEVEL DIFFLUENCE EAST OF THE TROUGH AXIS AND LOW-LEVEL CONVERGENCE IN THE VICINITY OF THE FRONT...WIDELY SCATTERED SHOWERS ARE OCCURRING MAINLY EAST OF THE FRONT WITHIN 240 NM EITHER SIDE OF A LINE FROM 19N62W TO 32N47W. THE REMAINDER OF THE SW NORTH ATLC IS UNDER THE INFLUENCE OF A SURFACE RIDGE ANCHORED BY A 1026 MB HIGH CENTERED OFF THE NORTH CAROLINA COAST NEAR 35N71W. NE TO E WINDS IN THE RANGE OF 15 TO 20 KT ARE EXPECTED TO PERSIST THROUGH LATE SUNDAY INTO MONDAY AS A COLD FRONT APPROACHES FROM THE WEST ACROSS THE GULF OF MEXICO BY MONDAY AFTERNOON. FARTHER EAST...AN UPPER LEVEL LOW IS CENTERED NEAR 26N25W. A SURFACE LOW HAS DRIFTED WEST OF THE UPPER LEVEL FEATURE AND CONTINUES TO WEAKEN AS A 1017 MB LOW CENTERED NEAR 30N38W. A SURFACE TROUGH BOUNDARY REMAINS ANALYZED FROM 23N34W TO 30N35W WITH ISOLATED SHOWERS OCCURRING WITHIN 240 NM EITHER SIDE OF THE BOUNDARY. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN