000 AXPZ20 KNHC 160336 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC SUN DEC 16 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0330 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS SW FROM THE COLOMBIAN COAST AT 08N78W TO 06N81W...THEN WIGGLES WESTWARD THROUGH 07N96W TO 06N108W WHERE LOW LEVEL WINDS INDICATE A TRANSITION TO AN ITCZ WHICH CONTINUES W TO BEYOND 07N140W. ISOLATED MODERATE CONVECTION IS STILL OBSERVED ALONG 04N BETWEEN 80-88W BUT SHOULD DISSIPATE WITHIN THE NEXT FEW HOURS. ISOLATED MODERATE CONVECTION IS STREAMING SW FROM THE CARIBBEAN AT 10N80W ACROSS PANAMA AND THE THE GULF OF PANAMA. SCATTERED MODERATE CONVECTION IS DECAYING WITHIN 75 NM OF 08N109W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED WITHIN 60 NM EITHER SIDE OF A LINE FROM 10N128W TO 07N135W TO 08N140W. ...DISCUSSION... ALOFT...A SHARP UPPER TROUGH EXTENDS SW INTO THE AREA WITH ITS MEAN AXIS ALONG 32N111W TO 19N140W. IMMEDIATELY TO THE NW...AN UPPER RIDGE IS COLLAPSING SE ACCOMPANIED BY 70-100 KT NORTHERLY WINDS FEEDING INTO THE UPPER TROUGH. AN AREA OF UPPER MOISTURE IS OBSERVED N OF 28N BETWEEN 117-140W. ANOTHER AREA OF UPPER MOISTURE IS NOTED E OF THE TROUGH AXIS AND RACING E ACROSS EASTERN ARIZONA AND ALL OF NEW MEXICO. A NARROW BAND OF DRY UPPER AIR IS OBSERVED WITHIN 180 NM EITHER SIDE OF A LINE FROM 20N140W TO 27N118W TO 33N111W. AN INVERTED UPPER TROUGH IS OBSERVED OVER THE DEEP TROPICS FROM 11N117W TO THE EQUATOR AT 127W AND EFFECTIVELY SEPARATES THE UPPER LEVEL FLOW ACROSS THE TROPICAL PORTION OF THE DISCUSSION AREA. UPPER LEVEL ANTICYCLONIC FLOW IS NOTED OVER THE DEEP TROPICS TO THE W OF THIS TROUGH. AN UPPER ANTICYCLONE HAS SHIFTED S OVER THE PACIFIC AT 13N95W WITH AN UPPER RIDGE NOW EXTENDING SW TO A SHARP CREST AT 10N117W. AN UPPER RIDGE ALSO EXTENDS E FROM THE ANTICYCLONE TO 10N82W. STRONG UPPER WESTERLIES CONTINUE TO ADVECT A DENSE PLUME OF UPPER MOISTURE NE ACROSS THE DISCUSSION AREA...WITHIN 360 NM EITHER SIDE OF A LINE FROM 11N140W TO 25N108W TO BEYOND 32N95W. SOME OF THE MOISTURE IS ADVECTED ANTICYCLONICALLY SE TOWARDS THE EQUATOR BETWEEN 127-138W. UPPER DIFFLUENCE ALONG THE SOUTHERN PERIPHERY OF THE LARGE ANTICYCLONE OVER THE SE PORTION ENHANCED THE SMALL AREAS OF CONVECTION PREVIOUSLY MENTIONED ALONG 04N BETWEEN 80-88W AND NEAR 08N109W. LOW LEVELS...AN INITIAL COLD FRONT EXTENDS ACROSS THE GULF OF CALIFORNIA ALONG 28N CONTINUING SW ACROSS THE BAJA PENINSULA TO OVER THE PACIFIC NEAR 24N120W WHERE IT IS BEGINNING TO DISSIPATE. A SECOND COLD IS APPROACHING THE N-CENTRAL PORTION. A SURFACE RIDGE EXTENDS FROM 28N140W TO 20N105W. NORTHERLY WINDS NE OF THE RIDGE FROM 25-32N BETWEEN 130W AND THE BAJA PENINSULA...HAVE DIMINISHED TO 10-15 KT...BUT SEAS CONTINUE AT 8-10 FT IN THE NW SWELL. EXPECTING ONLY A SW-W-NE 15-20 KT WIND SHIFT ALONG THE SECOND COLD FRONT LATE TONIGHT AND EARLY SUN WITH THE WINDS DIMINISHING TO 5-10 KT LATE SUN NEAR THE FRONT WHICH WILL DISSIPATE ON MON. SEAS SHOULD SUBSIDE TO 3-6 FT IN NW SWELL ALONG THE ENTIRE W COAST OF THE BAJA PENINSULA FROM LATE MON THROUGH LATE TUE. FURTHER S...NE TRADES CONTINUE AT 20-25 KT TO THE SW OF THE RIDGE ACROSS THE WATERS FROM 13-18N TO THE W OF 126W...WITH SEAS 9-11 FT IN MOSTLY NE SWELL. THE TRADES ARE AT 15-20 KT SURROUNDING THIS AREA FROM 09-22N TO THE W OF 115W WITH SEAS 7-8 FT IN MIXED N AND NE SWELL. THE FORECAST IS FOR A LOW LEVEL TROUGH TO FORM FROM 13N137W TO 18N136W ON MON MAINTAINING NE-E 20-25 KT WITHIN 180 NM OF THE TROUGH...WITH ENHANCED TRADES CONTINUING ELSEWHERE FROM ABOUT 08N-22N W OF 115W. CROSS EQUATORIAL SE SWELL WILL MIX WITH NE TRADE WINDS SWELL ACROSS THE WATERS S OF 06N W OF 120W ON MON. LOOKING FURTHER OUT...THE TROUGH OVER THE SW PORTION WILL DEEPEN ON MON NIGHT AS A STRONG COLD FRONT SWEEPS SE INTO THE SUBTROPICAL WATERS ACCOMPANIED BY N-NE 20-25 KT WINDS...WITH SEAS BUILDING 8-15 FT W OF THE FRONT. NW 20-25 KT WINDS AND SEAS 8-10 FT WILL ARRIVE AT THE W COAST OF THE BAJA PENINSULA ON TUE NIGHT. THE GRADIENT IS EXPECTED TO RELAX ON WED AS WINDS CLOCK TO THE NE AND DIMINISH TO 15-20 KT ALONG THE BAJA PENINSULA TO THE N OF 25N. GULF OF TEHUANTEPEC...WINDS ARE EXPECTED TO BECOME LIGHT AND VARIABLE LATE TONIGHT. BEST GUESS IS THE NEXT NORTHERLY EVENT WILL BEGIN LATE MON NIGHT...BUT PEAK AT ONLY 20 KT. ANOTHER STRONG EVENT NORTHERLY BEGINS THU EVENING WITH STORM CONDITIONS BY SUNRISE FRI. $$ NELSON