000 AXPZ20 KNHC 110343 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC SUN DEC 11 2011 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 0315 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... MONSOON TROUGH EXTENDS FROM 09N84W TO 06N92W WHERE LOW LEVEL WINDS SUGGEST THAT THE ITCZ BEGINS AND EXTENDS TO 06N100W TO 07N110W TO 07N121W TO 11N140W. NO SIGNIFICANT CONVECTION IS NOTED. ...DISCUSSION... AN UPPER LEVEL TROUGH EMBEDDED IN A VERY ACTIVE SRN STREAM BRANCH EXTENDS FROM 21N135W SSE TO 15N134W AND TO NEAR 07N134W. IT IS MOVING RAPIDLY EASTWARD WHILE SUPPORTING ACTIVE ITCZ BETWEEN 117W AND 121W. EARLIER DEEP CONVECTION NOTED NEAR AND OVER THE BASE OF THE TROUGH HAS SINCE DISSIPATED AS STRONG WLY UPPER SHEAR IN A MODERATE SUBSIDENT ENVIRONMENT PROTRUDES EASTWARD INTO THE FAR WESTERN PORTION OF THE AREA IN THE WAKE OF THE TROUGH. EXTENSIVE DEEP MID TO UPPER LEVEL MOISTURE IN THE FORM OF BROKEN HIGH CLOUDS CONTINUE TO STREAM NORTHEASTWARD INTO THE WESTERN AND CENTRAL SECTIONS OF THE AREA FROM THE DEEP CENTRAL PACIFIC TROPICS AND COMBING WITH ADDITIONAL MOISTURE PLUMES FROM ITCZ CONVECTION. THE MOISTURE THEN BECOMES DIRECTED BY THE TROUGH IN AN EASTWARD TRAJECTORY UP AN AROUND AN UPPER LEVEL ANTICYCLONE SITUATED NEAR 10N111W AND TOWARDS CENTRAL/SRN BAJA CALIFORNIA...AND TO ACROSS MUCH OF NORTHERN AND CENTRAL MEXICO AS WELL. THE TROUGH IS FORECAST TO QUICKLY DAMPEN OUT AS IT MOVES EASTWARD THROUGH LATE SUN...AND WHILE A SHARPENING DEEP UPPER TROUGH N OF THE AREA SWINGS ESE TOWARDS CALIFORNIA...AND FAR NW BAJA CALIFORNIA. THE ANTICYCLONE NEAR 10N111W DOMINATES THE REMAINDER OF THE NE PACIFIC ALLOWING FOR SUBSIDENCE AND DRY ENVIRONMENTAL CONDITIONS TO PREVAIL OVER THIS AREA. A SURFACE RIDGE EXTENDS FROM NEAR 30N135W SOUTHEASTWARD TO NEAR 20N111W. HIGH PRES COVERS THE AREA GENERALLY TO THE N OF 17N.THE COMBINATION OF THE RIDGE WITH ITCZ ASSOCIATED LOW PRESSURE IS SUSTAINING FRESH E-NE WINDS FROM 15N TO 23N W OF 130W WITH SEAS THERE IN THE 8 TO 11 FT RANGE. AS THE ABOVE UPPER TROUGH SHIFTS EASTWARD ACROSS SRN CALIFORNIA AND NRN BAJA MON...A 1029 MB HIGH WILL BECOME ESTABLISHED IN ITS WAKE NEAR 35N140W. THIS SET UP WILL BEGIN TO EXPAND THIS AREA OF NE TO E WINDS FROM ABOUT 08N TO 25N W OF 130W IN 24 HRS...AND FROM 08N TO 20N W OF 127W BY 48 HRS. SEAS SHOULD SUBSIDE SOME TO ABOUT 9 FT BY 48 HRS. GULF OF TEHUANTEPEC...N TO NE GALE FORCE WINDS OF UP TO 40 KT ARE SURGING SWD THROUGH THE GULF AS A STRONG PRES GRADIENT HAS SET UP OVER SRN MEXICO AND JUST INLAND THE GULF. SEAS OF UP TO 14 FT ARE POSSIBLE IN THE GULF. CONDITIONS ARE EXPECTED TO REMAIN WITH LITTLE CHANGE THROUGH SUN EVENING...THEN BEGIN TO DIMINISH GRADUALLY INTO MON AS THE GRADIENT SLACKENS WITH WINDS OF 25 TO 35 KT AND SEAS TO 12 FT. THE DEEP UPPER TROUGH FORECAST TO SWING ESE TOWARDS CALIFORNIA LATE SUN INTO MON...AS MENTIONED ABOVE...WILL DEEPEN INTO A CLOSED LOW OFFSHORE SRN CALIFORNIA LATE SUN AND THROUGH MON EVENING AS IT BREAKS OFF FROM NRN STREAM ENERGY. AN ASSOCIATED SURFACE WEAKENING COLD FRONT WILL EXTEND FROM THE LOW SW TO NEAR 22N123W BY MON EVENING. THE PRES GRADIENT BETWEEN THIS LOW AND THE 1029 MB HIGH NEAR 35N140W EARLY NEXT WEEK WILL INITIATE W TO NW WINDS OF 20 TO 25 KT N OF 22N W OF FRONT WITH NW SWELLS LEADING TO 10 TO 14 FT BY MON AFTERNOON BY THE WAVEWATCH MODEL GUIDANCE. SCATTERED SHOWERS ARE EXPECTED WITH THE LOW AND ALONG THE FRONT. ELSEWHERE W OF FRONT WINDS ARE EXPECTED TO BE N TO NE AT 20 KT WITH SEAS 8 TO 10 FT IN A NW TO N SWELL. SW TO W WINDS OF 20 KT ARE FORECAST TO THE E OF THE FRONT AND S OF THE LOW ON MON WITH SEAS 8 TO 10 FT IN A NW SWELL. GULF OF PAPAGAYO...NE WINDS OF 20 KT ARE EXPECTED TO PULSATE ON AND OFF PRIMARILY DURING THE LATE NIGHT AND EARLY MORNING IN DRAINAGE FLOW OFF THE LAND. HOWEVER...THESE WINDS ARE NOT EXPECTED TO COVER A LARGE ENOUGH AREA FOR MENTION IN THE NE PACIFIC HIGH SEAS FORECAST. $$ AGUIRRE