000 AXPZ20 KNHC 222138 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 2205 UTC SAT DEC 22 2012 TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. THE FOLLOWING INFORMATION IS BASED ON SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL ANALYSIS. BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2130 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH IS ALONG 07N77W TO 08N85W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 08N85W TO 07N110W TO 09N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION WITHIN 120 NM EITHER SIDE OF ITCZ W OF 120W. ...DISCUSSION... A SURFACE TROUGH...THE REMNANTS OF A FRONTAL BOUNDARY...EXTENDS FROM 31N122W TO 27N130W. NO SIGNIFICANT WINDS OR WEATHER ARE ASSOCIATED WITH THIS FEATURE. AN EARLIER ALTIMETER PASS SAMPLED LARGE NW SWELL UP TO 21 FT JUST TO THE N OF THE DISCUSSION AREA ALONG 132W...ABOUT 3 FT HIGHER THAN THE GFS WAVEWATCH AND ECWAVE SOLUTIONS...WHILE THE UKMET WAVE MODEL PROGGED A MAXIMUM OF 20 FT FOR THE SAME TIME PERIOD. THIS SET OF VERY HIGH ENERGY NW SWELL HAS PEAK WAVE PERIODS OF 17-19 FT. THE SWELL WILL GRADUALLY DECAY TO A COMBINED MAXIMUM OF ABOUT 12 FT IN 24 HOURS...WITH SEAS OF 8 FT OR GREATER REACHING THE EQUATOR BY 30 TO 36 HOURS. HIGH PRESSURE WILL BUILD EAST BEHIND THE TROUGH ALONG 26N THROUGH MONDAY NIGHT. THIS HIGH AND ACCOMPANYING RIDGE WILL BECOME THE DOMINANT SYNOPTIC FEATURE ACROSS THE REGION SATURDAY THROUGH TUESDAY WITH GENERALLY LIGHT TO MODERATE WINDS ACROSS THE NORTHERN WATERS. THE HIGH WILL ALSO ENHANCE NE-E TRADES S OF THE RIDGE AXIS AND N OF THE ITCZ. TRADES ARE ALREADY 20-25 KT IN THE W CENTRAL WATERS AS INDICATED BY RECENT ASCAT PASSES. THE SHIFTING RIDGE TO THE E WILL HELP TO EXPAND THE TRADES TO 117W IN ABOUT 48 HOURS WHILE COMBINED SEAS WILL REMAIN 10-13 FT IN MIXED NE WIND WAVES AND THE NW SWELL SET ACROSS THE AREA OF ENHANCED TRADES. AS THE RIDGE CONTINUES TO BUILD EASTWARD IN THE WAKE OF THE TROUGH...A TIGHT PRESSURE GRADIENT WILL ALSO SET UP NEAR THE BAJA CALIFORNIA PENINSULA WITH INVERTED TROUGHING LOCATED NEAR THE W COAST OF MEXICO. THIS MAY INDUCE NW TO N WINDS OF 20-25 KT IN THE SOUTHERN GULF OF CALIFORNIA AND WITHIN 120-180 NM W OF THE BAJA CALIFORNIA PENINSULA BY MONDAY MORNING. GAP WINDS... A 1029 MB HIGH PRESSURE CENTERED OVER SE LOUISIANA BEHIND A STRONG COLD FRONT HAS BEEN PRODUCING A VERY IMPRESSIVE GAP WIND EVENT THROUGH THE CHIVELA PASS INTO THE GULF OF TEHUANTEPEC. IT PEAKED AS A STORM FORCE WIND EVENT FOR 12-18 HOURS...BUT HAS NOW DIMINISHED TO GALE FORCE. THE IXTEPEC WEATHER STATION IN MEXICAN INLAND OF THE GULF OF TEHUANTEPEC STILL IS REPORTING 30 KT N WINDS AS OF 2100 UTC. ADDITIONALLY...A JUST ARRIVED OCEANSAT SCATTEROMETER FROM 1804 UTC SHOWS 35-40 KT WINDS IN THE GULF. HIGH SEAS OF ABOUT 18 FT ARE EMANATING FROM THE SOURCE REGION OF THE GULF OF TEHUANTEPEC WITH N-NE SWELL EXTENDING TO NEAR 112W. THESE SWELLS ARE MERGING WITH NW SWELL FROM THE NORTHERN PORTION OF THE DISCUSSION AREA NOTED ABOVE. THE PRESSURE GRADIENT IS FORECAST TO RELAX SIGNIFICANTLY OVER THE REGION LATE IN THE WEEKEND INTO EARLY NEXT WEEK WITH WINDS DIMINISHING BELOW GALE FORCE BY MID-DAY SUNDAY...THEN TO 20 KT OR LESS BY EARLY MONDAY MORNING. LOOKING AHEAD...A WEAKER COLD FRONT MAY MOVE THROUGH THE SW GULF OF MEXICO WEDNESDAY ALLOWING FOR A SHORT-LIVED MINIMAL GALE FORCE WIND EVENT IN THE GULF OF TEHUANTEPEC BEHIND ITS PASSAGE TO THE N BEGINNING WEDNESDAY EVENING. INCREASED TRADES IN THE SW CARIBBEAN IS AIDING NE-E 20-25 KT WINDS IN THE GULF OF PAPAGAYO THIS AFTERNOON...AS SEEN BY THE 1552 UTC ASCAT SCATTEROMETER PASS. THE WINDS IN THE CARIBBEAN WILL INCREASE FURTHER LATER TODAY AS A STRONG COLD FRONT CURRENTLY IN THE NW CARIBBEAN CONTINUES A TREK TO THE SE. THE AREA OF WINDS WILL SPREAD DOWNSTREAM TO ALONG 100W. RESULTANT SEAS WILL ALSO BUILD TO UP TO 12 FT. WINDS AND SEAS WILL THEN GRADUALLY DIMINISH AND SUBSIDE BY EARLY NEXT WEEK AS THE TRADES IN THE CARIBBEAN BACK OFF. LATEST MODEL GUIDANCE HAS TRENDED SLIGHTLY UPWARD WITH RESPECT TO THE STRENGTH OF NORTHERLY WINDS IN THE GULF OF PANAMA. FRESH TO STRONG WINDS ARE NOW ALSO LIKELY THERE FOR AN APPROXIMATELY 18 HOUR PERIOD COMMENCING SHORTLY. $$ COBB/LANDSEA