000 AXPZ20 KNHC 090333 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC TUE OCT 09 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 0300 UTC. ...SPECIAL FEATURE... TROPICAL DEPRESSION OLIVIA IS AT 15.7N 121.4W 1006 MB AT 09/0300 UTC. MAXIMUM SUSTAINED WIND SPEED IS 30 KT WITH GUSTS TO 40 KT. OLIVIA IS SHEARED FROM THE SW WITH SCATTERED MODERATE ISOLATED STRONG CONVECTION OBSERVED FROM120 TO 240 NM OUT OVER THE NE QUADRANT. OLIVIA IS FORECAST TO WEAKEN TO A REMNANT LOW PRESSURE CENTER EARLY TUE. 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 10N85W TO 10N92W TO 12N95W TO 07N113W TO 08N117W WHERE IT LOSES IDENTITY IN SOUTHERLY FLOW TO THE S OF TD OLIVIA. THE MONSOON TROUGH RESUMES SW OF OLIVIA AT 13N121W AND CONTINUES SW TO 07N138W 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 NE OF LINE FROM 06N82W TO 11N95W TO THE COAST OF CENTRAL AMERICA. SIMILAR CONVECTION IS NOTED ALONG THE MONSOON TROUGH WITHIN 60 NM EITHER SIDE OF A LINE FROM 09N95W TO 07N117W. ONLY ISOLATED MODERATE CONVECTION IS NOTED ALONG THE WESTERN BRANCH OF THE MONSOON TROUGH...ROUGHLY WITHIN 120 NM OF 14N128W. ...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 WILL APPROACH BUT STALL BEFORE ENTERING THE AREA. AN UPPER LEVEL ANTICYCLONE IS POSITIONED E OF TROPICAL STORM OLIVIA AT 15N116W WITH AN UPPER RIDGE EXTENDING N TO A NEARLY FLAT CREST AT 32N115W. AN UPPER RIDGE EXTENDS E FROM THE ANTICYCLONE TO ANOTHER ANTICYCLONE DEVELOPING OVER THE MEXICAN COAST AT 22N105W. A RIDGE ALSO EXTENDS W TO CREST AT 15N138W. A CLUSTER OF CONVECTION DISSIPATED JUST N OF THIS WESTERN RIDGE WITHIN 90 NM OF 17N140W. ITS DEBRIS MOISTURE IS NOW STREAMING NE AS A TROPICAL PLUME ALONG THE RIDGE PERIPHERY TO 25N126W WHERE CLOUD MOTION VECTORS INDICATE AN UPPER 50-70 KT JET BEGINS... AND CONTINUES NE ACROSS THE NORTHERN BAJA CALIFORNIA PENINSULA WHERE THE UPPER FLOW BECOMES ZONAL AT 30-40 KT. THE DEBRIS MOISTURE FROM OLIVIA IS ADVECTED N AND NE WITHIN THE UPPER RIDGE...THINNING AS IT STREAMS ACROSS THE SOUTHERN BAJA PENINSULA AND OVER THE AGRICULTURAL AREAS OF W CENTRAL MEXICO. 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 OVER THE PACIFIC AT 16N101W... WITH THE UPPER TROUGH CONTINUING S TO BASE OVER THE TROPICAL PACIFIC AT 11N102W. THE UPPER DIFFLUENCE E OF THE TROUGH AXIS... AND OVER THE E SEMICIRCLE OF THE UPPER CYCLONE...IS ENHANCING CONVECTION OVER CENTRAL MEXICO...AND ALSO RECENTLY JUST INLAND W MEXICO AT 17.5N101W. 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 TROPICAL PORTION OF THE DISCUSSION AREA. 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 101W. 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 THE RIDGE PERIPHERY AT 101W...THEN NE OVER MEXICO E OF 98W WHERE IT MERGES INTO A DENSE TROPICAL PLUME THAT CONTINUES NE ACROSS THE EASTERN GULF OF MEXICO AND MOST OF E FLORIDA AHEAD OF THE PARENT DEEP LAYERED TROUGH. 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 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 5-7 FT N OF 28N. REFRACTIVE SWELL RESULTS IN SEAS 3 TO 4 FT OVER THE GULF OF CALIFORNIA S OF 24.5N. LATEST GUIDANCE SUGGESTS SEAS 3-5 FT ALONG WESTERN BAJA THROUGH MIDDAY THU. 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 EXPECTED TO 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 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 FURTHER S 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 TONE DOWN THE GFS GUIDANCE WHEN POPULATING THE GRIDS E OF 105W. $$ NELSON