000 AXPZ20 KNHC 312210 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 2205 UTC FRI DEC 31 2010 TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2100 UTC. ...ITCZ... THE INTERTROPICAL CONVERGENCE ZONE IS ANALYZED FROM 1008 MB LOW PRES NEAR 07N79W TO 06N90W TO 08N110W TO 09N120W TO 08N140W. SCATTERED MODERATE CONVECTION IS FROM 05N TO 07N BETWEEN 78W AND 83W... AND FROM 05N TO 08N BETWEEN 99W AND 104W. AN EMBEDDED SURFACE TROUGH IS FROM 13N117W TO 07N120W. SCATTERED MODERATE CONVECTION IS FROM 08N TO 11N BETWEEN 115W AND 121W. ...DISCUSSION... A 1022 MB HIGH IS CENTERED NEAR 31N130W. A COLD FRONT IS FURTHER W FROM 32N140W TO 28N145W TO 28N155W MOVING E. THE PRESSURE GRADIENT BETWEEN THE SURFACE HIGH AND LOWER PRES ALONG THE ITCZ WILL PRODUCE AN AREA OF FRESH TRADE WINDS W OF 130W BETWEEN 08N AND 18N. THESE TRADES ARE EXPECTED TO RETREAT W OF 136W THROUGH SAT MORNING AS THE HIGH IS WEAKENED BY THE AFOREMENTIONED APPROACHING COLD FRONT. BY SAT NIGHT... A NEW HIGH WILL REBUILD W OF THE FRONT AND FRESH TRADES WILL EXPAND E TO 115W. MEANWHILE...THE PRES GRADIENT BETWEEN THE 1022 MB HIGH AND LOWER PRES OVER THE U.S. GREAT BASIN AND N CENTRAL MEXICO IS GENERATING FRESH TO STRONG NW TO N WINDS OFF THE COAST OF BAJA CALIFORNIA OUT TO 124W OVER N WATERS. AN UPPER LEVEL TROUGH IS N OF 5N BETWEEN 100W AND 133W. ELSEWHERE... AN UPPER LEVEL RIDGE IS OVER COLOMBIA AND THE E PACIFIC E OF 90W N OF THE EQUATOR SUPPORTING THE SURFACE LOW NEAR 07N79W. GAP WINDS... N TO NE WINDS THROUGH THE GULF OF PAPAGAYO ARE EXPECTED TO CONTINUE PULSING TO 20 KT WITH SEAS LESS THAN 8 FT IN THE EARLY MORNING HOURS THROUGH THE FORECAST PERIOD AS TRADE WINDS FROM THE WESTERN CARIBBEAN SEEP THROUGH THE CENTRAL AMERICA HIGH TERRAIN AND ARE ENHANCED BY MORNING MOUNTAIN DRAINAGE FLOW. TOWARD THE END OF THE PERIOD BY EARLY SUNDAY...NORTHERLY WINDS ARE EXPECTED TO BEGIN FILTERING THROUGH THE CHIVELA PASS ACROSS THE ISTHMUS OF TEHUANTEPEC INTO THE GULF OF TEHUANTEPEC AS A COLD FRONT SWEEPS ACROSS THE WESTERN GULF OF MEXICO. THIS EVENT WILL INTRODUCE N WINDS INITIALLY 20-25 KT...INCREASING THEREAFTER TO POTENTIALLY NEAR GALE FORCE BY LATE SUNDAY. $$ FORMOSA