000 AXNT20 KNHC 120553 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 105 AM EST THU JAN 12 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0515 UTC. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 09N13W TO 08N17W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 08N17W TO THE EQUATOR NEAR 44W THEN TO 01S47W. ISOLATED MODERATE CONVECTION IS FROM 02N-04N BETWEEN 33W-37W. ...DISCUSSION... GULF OF MEXICO... AN UPPER LEVEL TROUGH IS LOCATED OVER THE GULF THIS EVENING WITH ONE SHORTWAVE WELL NORTH OF THE REGION OVER THE MID-ATLC STATES AND ANOTHER SHORTWAVE LOCATED OVER THE EASTERN GULF NEAR 26N88W. BOTH OF THESE SHORTWAVES ARE SUPPORTING A COLD FRONT ANALYZED ACROSS THE SOUTHERN FLORIDA PENINSULA AND INTO THE SE GULF NEAR 26N81W THEN SW TO WESTERN CUBA NEAR 22N84W. MOSAIC DOPPLER RADAR AND LIGHTNING DATA INDICATE SCATTERED SHOWERS AND TSTMS OCCURRING EAST OF THE FRONT OVER PORTIONS OF WESTERN CUBA AND THE STRAITS OF FLORIDA S OF 24N. THE REMAINDER OF THE GULF IS UNDER THE INFLUENCE OF A WEAK SURFACE RIDGE ANCHORED BY A 1013 MB HIGH CENTERED NEAR 24N91W WITH GENERALLY CLEAR SKIES NOTED ON SATELLITE IMAGERY. SOUTHERLY RETURN FLOW HAS RE-ESTABLISHED ACROSS THE NORTHWESTERN PORTION OF THE GULF AS THE NEXT UPPER LEVEL SHORTWAVE CONTINUES PROGRESSING ACROSS THE SOUTHERN PLAINS. THIS FEATURE SUPPORTS A MORE POTENT COLD FRONT WHICH IS CURRENTLY ANALYZED OVER SE OKLAHOMA AND NORTH TEXAS. THE FRONT IS FORECAST TO EMERGE OFF THE TEXAS COAST BY MORNING WITH STRONG NORTHERLY WINDS EXPECTED BEHIND THE FRONT. HIGH PRESSURE IS THEN EXPECTED TO DOMINATE THROUGH THE UPCOMING WEEKEND. CARIBBEAN SEA... AN UPPER LEVEL RIDGE AXIS EXTENDS FROM THE TROPICAL NORTH ATLC NEAR 08N56W NW TO OVER HISPANIOLA NEAR 20N72W. WATER VAPOR IMAGERY INDICATES MOSTLY DRY AIR AND SUBSIDENCE IS LOCATED N OF 10N AND IS PROVIDING AN OVERALL STABLE ATMOSPHERE ACROSS THE CARIBBEAN THIS EVENING. SHORTWAVE INFRARED SATELLITE IMAGERY SHOWS TRANQUIL CONDITIONS PERSIST WITH E-NE TRADES IN THE RANGE OF 10 TO 20 KT...WITH HIGHER WINDS EXPECTED IN THE VICINITY OF THE COAST OF COLOMBIA. THE ONLY EXCEPTION TO THE FAIR WEATHER BASIN WIDE IS LOCATED OVER THE EXTREME NW PORTION. A COLD FRONT EXTENDS FROM THE SW NORTH ATLC ACROSS THE FLORIDA STRAITS AND WESTERN CUBA TO 21N85W IN THE YUCATAN CHANNEL. THE FRONT THEN BECOMES STATIONARY TO THE YUCATAN PENINSULA COAST NEAR 19N87W. ISOLATED SHOWERS ARE OCCURRING WITHIN 75 NM EITHER SIDE OF THE FRONT. ATLANTIC OCEAN... AN UPPER LEVEL RIDGE IS LOCATED OVER THE SW NORTH ATLC WITH RIDGE AXIS EXTENDING FROM OVER HISPANIOLA NEAR 20N70W TO BEYOND 32N65W. ON THE WESTERN PERIPHERY OF THE RIDGE...MOIST SW UPPER LEVEL FLOW IS NOTED BETWEEN THE RIDGE AND AN UPPER LEVEL SHORTWAVE TROUGH ACROSS THE MID-ATLC STATES. THIS TROUGH SUPPORTS A COLD FRONT ANALYZED FROM THE SOUTH CAROLINA COAST NEAR 33N79W TO 30N79W TO THE FLORIDA COAST NEAR 28N80W. SCATTERED SHOWERS AND ISOLATED TSTMS ARE OCCURRING WITHIN 90 NM EITHER SIDE OF A LINE FROM 32N76W TO 24N79W. FARTHER EAST...THE UPPER LEVEL RIDGING SUPPORTS A WEAKENING 1021 MB HIGH CENTERED NEAR 27N58W. HOWEVER...A NORTH-CENTRAL ATLC UPPER LEVEL TROUGH SUPPORTS A COLD FRONT DRAPED INTO THE DISCUSSION REGION THAT DISSECTS THE SURFACE RIDGE. THE COLD FRONT IS ANALYZED FROM 32N47W TO 28N58W THEN BECOMES STATIONARY TO 32N70W. MOISTURE LACKS WITH THIS FRONT...BUT A PRE-FRONTAL TROUGH ANALYZED FROM 25N52W TO 30N48W IS PROVIDING FOCUS FOR ISOLATED SHOWERS AND TSTMS WITHIN 180 NM EAST OF THE SURFACE TROUGH AND COLD FRONT. ON THE SOUTHERN PERIPHERY OF THE RIDGE...A SURFACE TROUGH IS ANALYZED FROM 16N57W TO 23N57W NE OF THE LEEWARD ISLANDS. LOW-LEVEL MOISTURE REMAINS LIMITED IN THE VICINITY OF THE TROUGH AXIS...HOWEVER A FEW ISOLATED SHOWERS ARE POSSIBLE FROM 12N-19N BETWEEN 52W-60W THROUGH THE OVERNIGHT HOURS. THE LAST SURFACE FEATURE OF IMPORTANCE THIS EVENING IS A SURFACE TROUGH EXTENDING INTO THE DISCUSSION AREA NEAR 32N34W TO 25N34W. WATER VAPOR IMAGERY SHOWS THAT AN UPPER LEVEL TROUGH IS IN PLACE OVER THE SURFACE TROUGH WITH AXIS ALONG 34W. ISOLATED SHOWERS ARE OCCURRING EAST OF THE SURFACE TROUGH OVER THE AREA FROM 25N-32N BETWEEN 27W-34W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN