000 AXPZ20 KNHC 310347 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC FRI AUG 31 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 0345 UTC. ...SPECIAL FEATURE... HURRICANE ILEANA IS CENTERED AT 21.2N 114.2W AT 31/0300 UTC. ILEANA IS MOVING NNW OR 335 DEG AT 05 KT WITH AN ESTIMATED MINIMUM CENTRAL PRESSURE IS 976 MB. MAXIMUM SUSTAINED WIND SPEED IS 75 KT WITH GUSTS TO 90 KT. SCATTERED MODERATE ISOLATED STRONG CONVECTION REMAINS CONCENTRIC WITHIN ABOUT 120 NM OF CENTER. THE CYCLONE IS MOVING OVER COOLER SEAS SURFACE WATERS AND IS BEGINNING TO WEAKEN. SEE THE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP4/WTPZ24 KNHC FOR MORE DETAILS. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM NW COAST OF COLOMBIA W ACROSS THE CARIBBEAN ALONG 11N TO THE PACIFIC COAST OF SOUTHERN NICARAGUA THEN CONTINUING WSW INTO AN EMBEDDED LOW PRESSURE NEAR 11N91.5W WITH THE TROUGH CONTINUING W TO 11N102W WHERE THE TROUGH LOSES IDENTITY IN THE BROAD CYCLONIC CIRCULATION ASSOCIATED WITH TROPICAL CYCLONE ILEANA. THE MONSOON TROUGH BECOMES ESTABLISHED AGAIN SW OF ILEANA NEAR 14N117W AND CONTINUES SW TO 10N122W THEN WESTWARD TO BEYOND 10N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION...VERIFIED BY LIGHTNING DATA...IS OBSERVED WITHIN 240 NM EITHER SIDE OF A LINE FROM 05N77W TO 14N107W. THE EMBEDDED LOW PRESSURE CENTER AT 11N91.5W IS EXPECTED TO CONTINUE NW WITH CYCLONIC WINDS AT 20 TO 25 KT EXPANDING OUT TO ABOUT 270 NM FROM THE CENTER ON FRI. ...DISCUSSION... AN UPPER LEVEL TROUGH DOMINATES THE UPPER LEVELS OF THE EASTERN N PACIFIC WITH THE MEAN TROUGH AXIS EXTENDING INTO THE DISCUSSION AREA FROM 32N132W TO 22N137W. AN UPPER LEVEL ANTICYCLONE IS CENTERED AT 20N137W WITH ITS ENVELOPE OF ANTICYCLONIC UPPER FLOW COVERING THE AREA FROM 10N TO 21N BETWEEN 130W AND 142W. THESE FEATURES COMBINE TO DRY OUT THE UPPER LEVELS TO THE W OF A LINE EXTENDING FROM 30N113W TO 00N138W. THE UPPER ANTICYCLONE OVER TROPICAL CYCLONE ILEANA HAS A RIDGE EXTENDING NE TO 28N108W AND A RIDGE ALSO EXTENDS SW TO A CREST AT 19N129W. SOME DEBRIS MOISTURE FROM ILEANA CONVECTION IS ADVECTED SW IN A 250 NM WIDE PLUME WITH AXIS 17N110W TO 08N127W. SOME OF THE TROPICAL CYCLONES DEBRIS MOISTURE ALSO CONTINUES TO SPREAD NE ACROSS THE SOUTHERN BAJA PENINSULA AND GULF OF CALIFORNIA...AND IS NOW SPREADING NE ACROSS NW MEXICO. AN UPPER CYCLONE IS QUASI STATIONARY OVER THE NW CARIBBEAN AT 20N86W WITH AN UPPER TROUGH EXTENDING S TO THE COSTA RICA AND NICARAGUA BORDER. UPPER DIFFLUENCE E OF THIS TROUGH IS ENHANCING SIGNIFICANT CONVECTION OVER NICARAGUA AND HONDURAS. THE UPPER FLOW IS ALSO DIFFLUENT OVER THE TROPICAL E PACIFIC E OF 110W WHERE CONVECTION ALONG THE MONSOON TROUGH IS ENHANCED AS PREVIOUSLY DESCRIBED. THE RESULTANT DENSE UPPER DEBRIS MOISTURE IS ADVECTED SW ACROSS THE EQUATOR BETWEEN 80W AND 108W. ELSEWHERE AT THE LOW LEVELS...SOUTHWESTERLY MONSOONAL FLOW AT 15 TO 20 KT WINDS WITH SEAS 8 TO 11 FT ARE OBSERVED FROM 10N TO 21N BETWEEN 104W AND 124W...MERGING WITH THE SOUTHERLY WIND WAVE OVER THE S SEMICIRCLE OF TROPICAL CYCLONE ILEANA. LONG PERIOD CROSS EQUATORIAL SOUTHWESTERLY SWELL AT 14 TO 19 SECONDS IS EXPECTED TO PROPAGATE N TO ALONG 07N BETWEEN 78W AND 88W RESULTING IN SEAS TO 9 FT. MIXED SOUTHERLY LONG PERIOD SWELL AT 15 TO 18 SECONDS IS NOTED FROM THE EQUATOR TO 20N BETWEEN 90W AND 130W BUT SHOULD BEGIN TO SUBSIDE OVER THE NEXT COUPLE OF DAYS. $$ NELSON