000 AXPZ20 KNHC 082151 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 2205 UTC MON OCT 08 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 FEATURE... TROPICAL STORM OLIVIA IS STATIONARY AT 16.3N 121.2W 1004 MB AT 08/2100 UTC. MAXIMUM SUSTAINED WIND SPEED IS 40 KT WITH GUSTS TO 50 KT. OLIVIA IS SHEARED FROM THE SW WITH SCATTERED MODERATE ISOLATED STRONG CONVECTION OBSERVED WITHIN 270 NM OVER NE QUADRANT. A CLUSTER OF SCATTERED MODERATE CONVECTION IS OBSERVED IN THE SW QUADRANT...WITHIN 30 NM OF 16N121.5W. OLIVIA IS FORECAST TO WEAKEN TO A TROPICAL DEPRESSION TONIGHT AS IT MOVES SLOWLY NW AND THEN W AND EVENTUALLY WESTWARD. FOR FURTHER DETAILS SEE AWIPS/WMO HEADERS MIATCMEP5 AND WTPZ25 KNHC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS W ACROSS NORTHERN COSTA RICA TO THE PACIFIC COAST AT 11N86W TO 09N89W TO 11N94W TO 08N109W TO 08N115W WHERE IT LOSES IDENTITY IN SOUTHERLY FLOW TO THE S OF TS OLIVIA. THE MONSOON TROUGH RESUMES SW OF OLIVIA AT 13N121W AND CONTINUES SW TO 06N138W WHERE LOW LEVEL WINDS INDICATE A TRANSITION TO AN ITCZ WHICH IN TURN CONTINUES W TO BEYOND 06N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION...WITH OCCASIONAL LIGHTNING...IS NOTED N OF LINE FROM 03N77W TO 07N88W TO 08N100W TO THE COAST OF CENTRAL AMERICA. SIMILAR CONVECTION IS NOTED ALONG THE MONSOON TROUGH WITHIN 90 NM EITHER SIDE OF A LINE FROM 09N100W TO 07N117W. ONLY ISOLATED MODERATE CONVECTION IS NOTED ALONG THE WESTERN BRANCH OF THE MONSOON TROUGH... ROUGHLY WITHIN 180 NM EITHER SIDE OF A LINE FROM 14N127W TO 08N131W. ...DISCUSSION... UPPER LEVEL SHORTWAVE TROUGHS HAVE BEEN ROTATING ACROSS THE NW PORTION OF THE DISCUSSION AREA WITH UPPER MOISTURE NOTED W OF THE TROUGH AXIS. AN ASSOCIATED SURFACE COLD FRONT IS APPROACHING THE NW PORTION BUT IS FORECAST TO STALL BEFORE ENTERING THE AREA. AN UPPER LEVEL ANTICYCLONE IS POSITIONED E OF TROPICAL STORM OLIVIA AT 17N114W WITH AN UPPER RIDGE EXTENDING N TO A FLAT CREST AT 32N BETWEEN 116W AND 107W. AN UPPER RIDGE ALSO EXTENDS E FROM THE ANTICYCLONE TO CREST OVER MEXICO AT 21N103W WHERE THERE IS SOME EVIDENCE OF A NEW UPPER ANTICYCLONE FORMING. A RIDGE ALSO EXTENDS W TO CREST AT 15N137W. A CLUSTER OF SCATTERED MODERATE CONVECTION IS OBSERVED JUST N OF THIS WESTERN RIDGE... WITHIN 90 NM OF 17N140W. THE CONVECTION SEEMS TO HAVE MATURED BUT ITS DEBRIS MOISTURE HAS ORGANIZED INTO A NEW TROPICAL PLUME ALONG THE RIDGE PERIPHERY TO 24N128W WHERE CLOUD MOTION VECTORS INDICATE AN UPPER 50-70 KT JET HAS REFORMED...AND CONTINUES NE ACROSS THE NORTHERN BAJA CALIFORNIA PENINSULA WHERE THE UPPER FLOW BECOMES ZONAL. THE DEBRIS MOISTURE FROM OLIVIA IS ADVECTED N AND NE WITHIN THE UPPER RIDGE...THINNING AS IT STREAMS ACROSS THE SOUTHERN BAJA PENINSULA. AN UPPER SHORTWAVE TROUGH IS MOVING THROUGH EASTERN N AMERICA TRAILING A TROUGH SW ACROSS THE GULF OF MEXICO AND OVER CENTRAL MEXICO THROUGH AN UPPER CYCLONE 17N101W...WITH THE UPPER TROUGH CONTINUING S TO BASE OVER THE TROPICAL PACIFIC AT 10N100W. THE UPPER DIFFLUENCE E OF THE TROUGH...AND THE UPPER CYCLONE...IS ENHANCING CONVECTION OVER CENTRAL MEXICO...AND ALSO RECENTLY JUST INLAND W MEXICO AT 17.5N100W. THE DEBRIS MOISTURE IS ADVECTED NE ACROSS THE GULF OF MEXICO. THE SOUTHERN EXTENT OF THIS UPPER TROUGH CONTINUES TO SEPARATE THE UPPER FLOW OVER THE TROPICS. AN UPPER ANTICYCLONE OVER THE WESTERN CARIBBEAN AT 13N81W HAS ITS ANTICYCLONIC ENVELOPE EXTENDING S OVER THE DISCUSSION AREA TO THE N OF 07N AND E OF 100W. THE ASSOCIATED UPPER DIFFLUENCE IS SUPPORTING THE CONVECTION ALONG THE EASTERN SEGMENT OF THE MONSOON TROUGH AS PREVIOUSLY DESCRIBED. DENSE DEBRIS MOISTURE IS OBSERVED WITHIN THIS UPPER RIDGE TURNING N ALONG 100W...THEN NE OVER MEXICO E OF 97W WHERE IT MERGES INTO A DENSE TROPICAL PLUME THAT CONTINUES NE ACROSS THE EASTERN GULF OF MEXICO AND MOST OF E FLORIDA. ELSEWHERE AT THE LOW LEVELS...SURFACE HIGH PRESSURE CONTINUES TO MEANDER NEAR 28N127W WITH BROAD RIDGING COVERING THE DISCUSSION AREA N OF 21N W OF THE BAJA PENINSULA. NW WINDS ALONG THE E PERIPHERY OF THIS SURFACE RIDGE ARE AT AT 10-15 KT ALONG THE ENTIRE W COAST OF THE BAJA PENINSULA...WITH SEAS 4-5 FT IN NW SWELL TO THE S OF 28N...AND 5-6 FT N OF 28N. REFRACTIVE SWELL RESULTS IN SEAS 3 TO 4 FT OVER THE GULF OF CALIFORNIA S OF 24.5N. NW WINDS ARE EXPECTED TO INCREASE BRIEFLY TO 15-20 KT N OF 28N E OF 117W ON TUE NIGHT...WITH SEAS BUILDING 5-7 FT. THE GRADIENT WILL RELAX AGAIN ON WED THROUGH LATE THU SUPPORTING NW 10-15 KT AND SEAS OF 3-5 FT ALONG THE ENTIRE W COAST OF BAJA. GUIDANCE SHOWS A ROUND OF W SWELL REACHING THE BAJA PENINSULA S OF 27N LATE THU NIGHT...WITH SEAS BUILDING TO 5-7 FT. NW WINDS INCREASE TO 15-20 KT ALONG ENTIRE W COAST OF BAJA ON FRI NIGHT. GAP WINDS...NORTHERLY WINDS WILL PULSE AT 20-25 KT THROUGH AND DOWNSTREAM THE GULF OF TEHUANTEPEC TO REACHING NEAR 12.597W THROUGH TUE AFTERNOON...THEN GUIDANCE SUGGESTS WINDS WILL DIMINISH BRIEFLY TO 10-15 KT TUE EVENING. GUIDANCE SUGGESTS A NEW PULSE WILL RESUME LATE TUE NIGHT AND CONTINUE WED INCREASING TO 25-30 KT AROUND SUNRISE THU. BY THEN EXPECT A COUPLE OF SURFACE LOWS TO HAVE DEVELOPED ALONG 10N-11N WITHIN THE MONSOON TROUGH... WITH THE NORTHERLY DRAINAGE FLOW THROUGH TEHUANTEPEC ENHANCING THE FLOW OVER THE N SEMICIRCLE OF THE LOWS. CONTINUING TO USE A BLEND OF GLOBAL GUIDANCE TO POPULATE GRIDS E OF 105W. $$ NELSON