000 AXPZ20 KNHC 020352 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC SUN SEP 02 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 0315 UTC. ...SPECIAL FEATURES... TROPICAL STORM ILEANA...CENTERED AT 23.1N 120.4W AT 02/0300 UTC. ILEANA IS MOVING W OR 270 DEG AT 07 KT WITH AN ESTIMATED MINIMUM CENTRAL PRESSURE OF 1004 MB. MAXIMUM SUSTAINED WIND SPEED IS 35 KT WITH GUSTS TO 45 KT. SCATTERED MODERATE CONVECTION IS NOTED WITHIN 90 NM NW AND WITHIN 30 NM SE SEMICIRCLES OF CENTER. THE CYCLONE IS MOVING OVER INCREASINGLY COOLER SEAS SURFACE WATERS AND MORE STABLE ATMOSPHERIC CONDITIONS AND IS EXPECTED TO WEAKEN TO A REMNANT LOW PRES TONIGHT. SEE THE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP4/WTPZ24 KNHC FOR MORE DETAILS. TROPICAL LOWS...LOW PRES IS AT 13.5N 104.5W WITH SCATTERED MODERATE ISOLATED STRONG CONVECTION NOTED WITHIN 120 NM OVER THE W SEMICIRCLE OF CENTER. A SECOND LOW PRES IS AT 16.5N104W 1007 MB WITH SCATTERED MODERATE ISOLATED STRONG CONVECTION OBSERVED WITHIN 120 NM OF CENTER. GLOBAL GUIDANCE SUGGESTS THAT THESE SURFACE LOWS WILL MERGE REACHING NEAR 16N110W LATE SUN AND CONTINUE NW TO NEAR 17N114W ON MON WITH TROPICAL CYCLONE DEVELOPMENT LIKELY DURING THE 48 HOUR PERIOD. CURRENTLY THE PRESSURE GRADIENT BETWEEN STRONG HIGH PRESSURE BRIDGING SW ACROSS CENTRAL AMERICA AND LOW PRESSURE WITHIN THE BROAD MONSOON TROUGH HAS ENHANCED EASTERLY WINDS TO 20 TO 30 KT WITHIN 120 NM EITHER SIDE OF A LINE FROM 18N105W TO 13N97W. THE GRADIENT IS ALSO TIGHT OVER S SEMICIRCLE OF THE SOUTHERNMOST SURFACE LOW AND S TO SW WINDS ARE AT 20 TO 25 KT WITH SEAS 9 TO 10 FT WITHIN THE AREA FROM 10N TO 13N BETWEEN 101W AND 110W. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS W FROM THE PANAMA/COLOMBIAN BORDER ACROSS PANAMA AND THE E PACIFIC TO 08N96W WHERE THE TROUGH BECOMES ILL-DEFINED. THE MONSOON TROUGH BECOMES DEFINED AGAIN SW OF THE TROPICAL SURFACE LOWS NEAR 14N108W AND EXTENDS SW 10N130W TO 11N140W. ISOLATED MODERATE AND STRONG CONVECTION IS OBSERVED TO THE N OF 03N BETWEEN 82W AND 102W. SCATTERED MODERATE CONVECTION IS NOTED ELSEWHERE FROM 07N TO 14N BETWEEN 103W AND 115W. ...DISCUSSION... A LONG WAVE UPPER TROUGH DOMINATES THE EASTERN N PACIFIC WITH AN EMBEDDED SHORTWAVE TROUGH EXTENDING INTO THE DISCUSSION AREA FROM 32N128W TO 26N126W. IMMEDIATELY TO THE SW AN UPPER LEVEL ANTICYCLONE IS CENTERED AT 21N139W WITH A RIDGE EXTENDING E TO A RELATIVELY SHARP CREST AT 23N129W. ANOTHER UPPER ANTICYCLONE IS OVER THE NEW MEXICO/TEXAS BORDER NEAR 33N104W...WITH A RIDGE EXTENDING SW TO A SHARP CREST AT 26N122W WHICH IS JUST TO THE N OF THE DISSIPATING TROPICAL CYCLONE ILEANA. SOME OF THE DEBRIS MOISTURE FROM ILEANA CONCENTRATES INTO A 330 NM WIDE PLUME EXTENDING SW TO NEAR 14N138W WHERE IT ALMOST EVAPORATES. SOME OF THE TROPICAL CYCLONE DEBRIS MOISTURE IS STILL EVIDENT ALONG A VERY NARROW LINE FROM EXTREME NORTHERN BAJA CALIFORNIA PENINSULA TO CENTRAL ARIZONA WHERE THE MOISTURE PLUMES WIDENS AS IT CONTINUES NE ACROSS NORTHWESTERN NEW MEXICO. OTHERWISE THE UPPER LEVELS ARE FAIRLY DRY N OF 20N W OF 123W. AN UPPER TROUGH ORIGINATING IN THE CENTRAL N ATLANTIC CONTINUES SW ACROSS THE NW CARIBBEAN TO BASE OVER THE TROPICAL E PACIFIC AT 13N89W. AN AREA OF UPPER DIFFLUENCE WAS INDUCED OVER THE SW CARIBBEAN AND OVER SOUTHERN PORTIONS OF CENTRAL AMERICA. THE RESULTANT DENSE UPPER DEBRIS MOISTURE IS ADVECTED SW MERGING WITH THE ADDITIONAL DEBRIS MOISTURE ORIGINATING FROM THE TROPICALS LOWS...WITH THE SOUTHERN EXTENT OF THE MOISTURE ALONG 03N BETWEEN 80W AND 110W. ELSEWHERE AT THE LOW LEVELS...SURFACE HIGH PRESSURE IS CENTERED N OF THE AREA NEAR 35N148W AND IS PRODUCING LIGHT TO MODERATE NE FLOW ACROSS THE AREA W OF TROPICAL CYCLONE ILEANA. $$ NELSON