000 AXPZ20 KNHC 022156 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 2205 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2145 UTC. ...SPECIAL FEATURES... .A COUPLE OF TROPICAL LOW PRESSURE SYSTEMS EMBEDDED WITHIN THE PACIFIC MONSOON TROUGH HAVE MERGED INTO TD TEN-E AT 18.3N 109.6W 1006 MB AT 2100 UTC...MOVING W-NW OR 290 DEG AT 15 KT ALONG THE SOUTHERN PERIPHERY OF A MID TO UPPER LEVEL RIDGE. CURRENTLY SCATTERED MODERATE TO STRONG CONVECTION IS OBSERVED WITHIN 150 NM OF THE CENTER WITH BANDING FEATURES DEVELOPING OVER THE NE SEMICIRCLE AS WELL AS THE S QUADRANT. MAXIMUM SUSTAINED WINDS ARE 30 KT WITH GUSTS TO 40 KT. ALTHOUGH THE SYSTEM IS EXPERIENCING NORTHEASTERLY WIND SHEAR CONTINUED SLOW DEVELOPMENT IS EXPECTED...AND TROPICAL STORM FORCE WINDS ARE FORECAST WITHIN 12 HOURS WITH WINDS EXPECTED TO MAX AROUND 40 KT GUSTING TO 50 KT ON MON...MAINLY OVER THE N SEMICIRCLE AND SE QUADRANT. BY TUE THE SYSTEM WILL TRACK SLOWER OVER A COOLER SURFACE WATERS AND BEGIN TO WEAKEN AND THE CYCLONE IS FORECAST TO BE BELOW TROPICAL STORM FORCE AROUND MIDDAY WED. SEE THE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP5/WTPZ25 KNHC FOR MORE DETAILS. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS W TO E OVER THE SW CARIBBEAN ALONG 11N FROM THE COLOMBIAN COAST TO ACROSS NORTHERN COSTA RICA...THEN TURNS SW OVER THE PACIFIC TO 07N92W...THEN NW TO 10N98W WHERE IT LOSES IDENTITY IN THE BROAD CYCLONIC CIRCULATION ASSOCIATED WITH DEVELOPING TD TEN-E. THE MONSOON TROUGH BECOMES DEFINED AGAIN SW OF THE TD 10-E NEAR 16N109W...AND EXTENDS SW TO 10N120W...THEN WESTWARD TO BEYOND 10N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS OBSERVED ALONG THE EASTERN SEGMENT OF THE MONSOON TROUGH...FROM 04N TO 12N BETWEEN 79W AND 95W...AND ALSO OVER THE CARIBBEAN S OF 12N BETWEEN 75W AND 84W. SIMILAR CONVECTION IS OBSERVED WITHIN 90 NM OF 07N104W...AND ALSO WITHIN THE THE SOUTHERLY LOW LEVEL FLOW SE OF TD 10-E... APPROXIMATELY WITHIN 120 NM EITHER SIDE OF A LINE FROM 18N104W TO 12N113W. ...DISCUSSION... A UPPER SHORTWAVE TROUGH EXTENDS SW INTO THE DISCUSSION AREA FROM 32N126W TO 24N130W. IMMEDIATELY TO THE SW AN UPPER LEVEL ANTICYCLONE HAS SHIFTED WESTWARD TO 22N141W BUT ITS RIDGE STILL EXTENDS E TO A SHARP CREST AT 22N134W. THE NE PORTION OF THE DISCUSSION AREA IS DOMINATED BY AN UPPER ANTICYCLONE CENTERED OVER OLD MEXICO/TEXAS BORDER NEAR 29N101W...WITH AN UPPER RIDGE EXTENDING W ACROSS OLD MEXICO ALONG 28N TO A CREST OVER THE PACIFIC AT 28N123W. THE ANTICYCLONIC FLOW ALONG THE SOUTHERN PERIPHERY OF THIS RIDGE IS STEERING TD TEN-E WESTWARD BUT TURNS CYCLONIC INTO AN SMALL UPPER TROUGH DIRECTLY OVER THE REMNANT LOW 1008 MB PRES OF TROPICAL CYCLONE ILEANA AT 22.5N123W. A TROPICAL UPPER CYCLONE IS AT 10N120W SETTING UP A LARGE AREA OF DIFFLUENCE TO ITS NE AND TO THE S OF THE DOMINATE UPPER MEXICAN RIDGE...ROUGHLY IN THE AREA FROM 10N TO 20N BETWEEN 100W AND 115W. THIS DIFFLUENCE IS ENHANCING THE CONVECTION ASSOCIATED WITH TD TEN-E...AND THE CONVECTION ALONG THE MONSOON TROUGH AS PREVIOUSLY DESCRIBED. MOST OF THE RESULTANT DENSE UPPER DEBRIS MOISTURE IS ADVECTED SW TO ALONG 03N BETWEEN 100W AND 115W. SCATTERED MODERATE CONVECTION IS NOTED OVER THE GULF OF CALIFORNIA S OF 26N AND SCATTERED STRONG CONVECTION...ACCOMPANIED BY NUMEROUS LIGHTNING STRIKES...IS CURRENTLY FLARING OVER THE BAJA PENINSULA BETWEEN 25N AND 27N. THE DEBRIS MOSITURE FROM THESE AREAS IS SPREADING ANTICYCLONICALLY NW AROUND THE DOMINATE MEXICAN UPPER RIDGE... BACK E OVER THE BAJA PENINSULA AND THE SEA OF CORTEZ AS FAR N AS 29.5N. A BROAD INVERTED UPPER TROUGH IS NOTED OVER THE FAR SE PORTION OF THE DISCUSSION AREA EXTENDING N FROM AN UPPER CYCLONE S OF THE AREA AT 02S86W. ASSOCIATED WEAK UPPER DIFFLUENCE EITHER SIDE OF THIS UPPER TROUGH IS SUPPORTING THE WESTWARD MOVING CONVECTION ALONG THE E SEGMENT OF THE MONSOON TROUGH AS PREVIOUSLY MENTIONED. 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 THE REMNANTS OF TROPICAL CYCLONE ILEANA. $$ NELSON