000 AXPZ20 KNHC 080402 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 0405 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0345 UTC. ...SPECIAL FEATURE... TROPICAL STORM OLIVIA AT 16.2N 120.9W 998 MB AT 08/0300 UTC MOVING N OR 355 DEGREES AT 06 KT IN RESPONSE TO AN UPPER CYCLONE E OF THE CENTER NEAR 13.5N116W. MAXIMUM SUSTAINED WIND SPEED IS 50 KT WITH GUSTS TO 60 KT. NUMEROUS MODERATE TO STRONG CONVECTION WITHIN 45 NM OF CENTER. SCATTERED MODERATE ISOLATED STRONG CONVECTION ELSEWHERE WITHIN 120 NM W AND 210 NM E SEMICIRCLES OF CENTER. OLIVIA MAY STRENGTHEN SLIGHTLY OVER THE DAY OR SO THEN THE FORECAST TRACK WILL MOVE OVER COOLER OCEAN WATERS. FOR FURTHER DETAILS SEE AWIPS/WMO HEADERS MIATCMEP5 AND WTPZ25 KNHC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS W ACROSS THE SOUTHERN CARIBBEAN BETWEEN 11N-12N FROM EXTREME N COLOMBIA TO ACROSS CENTRAL COSTA RICA TO THE PACIFIC COAST AT 09N84W...THEN CONTINUES W TO 08N112W WHERE IT LOSES IDENTITY IN SOUTHERLY FLOW TO THE S OF TS OLIVIA. THE MONSOON TROUGH RESUMES SW OF OLIVIA AT 13N123W TO 08N135W WHERE LOW LEVEL WINDS INDICATE A TRANSITION TO AN ITCZ WHICH CONTINUES W TO BEYOND 08N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS OBSERVED WITHIN 90 NM EITHER SIDE OF A LINE FROM 07N81W TO 09.5N85W TO 09N90W AND WITHIN 30 NM EITHER SIDE OF A LINE FROM 13N94W TO 09N89W. SCATTERED MODERATE CONVECTION IS OBSERVED WITHIN 30 NM EITHER SIDE OF A LINE FROM 07N93W TO 08.5N100.5W TO 07N105W TO 10N112W...AND FROM 06N TO 11N BETWEEN 128W AND 137W. SCATTERED MODERATE ISOLATED STRONG CONVECTION...ACCOMPANIED BY NUMEROUS LIGHTNING STRIKES...IS OBSERVED OVER AND WITHIN 15 NM OF THE PACIFIC COAST OF CENTRAL AMERICA FROM 86W TO 93W. ...DISCUSSION... A SHORTWAVE TROUGH HAS MOVED OVER THE NW PORTION OF THE DISCUSSION AREA ALONG 32N132W TO 26N131W WITH A BAND OF UPPER MOISTURE ROTATING THROUGH THE TROUGH AND ACROSS THE CALIFORNIA COAST FROM 34N-38N. A SECOND BAND OF UPPER MOISTURE IS MOVING E ACROSS THE NORTHERN BAJA CALIFORNIA PENINSULA CONTINUING E ACROSS SOUTHERN ARIZONA AND NEW MEXICO MERGING WITH A SIGNIFICANT MOISTURE BAND MOVING E ACROSS THE ENTIRE SE CONUS. AN UPPER LEVEL ANTICYCLONE IS POSITIONED E OF TROPICAL STORM OLIVIA AT 13.5N116W WITH UPPER RIDGES EXTENDING N BEYOND 32N115W...SE TO A CREST AT 14.5N105W AND W TO A CREST AT 15N131W. AN UPPER JET DETECTED BY CLOUD MOTION VECTORS ALONG THE NW PERIPHERY OF THE ANTICYCLONE APPEARS TO HAVE WEAKENED TO ABOUT 50 KT AS IT CONTINUES THROUGH POINTS 29N127W TO 32N117W. THE DEBRIS MOISTURE FROM OLIVIA IS ADVECTED N AND NE ACROSS THE UPPER RIDGE AT 23N116W WHERE IT TURNS SE AND APPEARS TO REMAIN W OF THE MEXICAN COAST AS IT RETURNS BACK S OVER THE DEEP TROPICS. AN UPPER SHORTWAVE TROUGH OVER THE CENTRAL CONUS EXTENDS SW ACROSS THE WESTERN GULF OF MEXICO AND OVER CENTRAL MEXICO TO BASE NEAR 16N101W. THE UPPER DIFFLUENCE E OF THE TROUGH IS ENHANCING CONVECTION OVER MEXICO TO THE E OF 100W...WITH THE DEBRIS MOISTURE ADVECTED NE ACROSS THE GULF OF MEXICO. AN UPPER ANTICYCLONE OVER THE WESTERN CARIBBEAN AT 16N81W HAS ITS ANTICYCLONIC ENVELOPE EXTENDING S OVER THE DISCUSSION AREA TO THE N OF 05N AND E OF 98W. THE ASSOCIATED UPPER DIFFLUENCE IS SUPPORTING THE CONVECTION ALONG THE EASTERN SEGMENT OF THE MONSOON TROUGH AS PREVIOUSLY DESCRIBED. DENSE DEBRIS MOISTURE IS OBSERVED OVER THE AREA N OF 05W E OF 91W...AND FOR THE MOST PART IS ADVECTED N ACROSS CENTRAL AMERICA TO THE E OF 91W. ELSEWHERE AT THE LOW LEVELS...SURFACE HIGH PRESSURE IS NEAR 29N127W WITH BROAD RIDGING COVERING THE DISCUSSION AREA N OF 22N W OF THE BAJA PENINSULA. THE NW WINDS HAVE DIMINISHED THIS AFTERNOON TO 15-20 KT E OF THE RIDGE IN THE AREA N OF 27N BETWEEN 117W AND THE NORTHERN BAJA CALIFORNIA PENINSULA...WITH SEAS CONTINUING AT 5-8 FT IN NW SWELL. EXPECT THESE NW WINDS TO FURTHER DIMINISH TO 10-15 KT ALONG THE ENTIRE W COAST OF THE BAJA PENINSULA ON MON...WITH SEAS OF 4-7 FT IN NW SWELL... SUBSIDING TO 3-5 FT WED AND THU. EXTENDED GUIDANCE SHOWS THE SURFACE HIGH MEANDERING NEAR 28N125W LATE THIS WEEK...BUT THE GRADIENT WILL TIGHTEN AGAIN ALONG THE NW COAST OF BAJA LATE FRI WITH NW WINDS INCREASING TO 15-20 KT AND SEAS BUILDING 4-7 FT INTO THE WEEKEND. GAP WINDS...NORTHERLY WINDS AT 20-25 KT ARE EXPECTED TO PULSE AGAIN ACROSS THE GULF OF TEHUANTEPEC IN A FEW HOURS AND INCREASE TO 20-30 KT LATE MON NIGHT...RELAXING TO 20-25 KT TUE NIGHT...BUT INCREASING AGAIN TO 25-30 KT LATE WED NIGHT. THE STRONGEST DRAINAGE FLOW WILL OCCUR LATE EACH NIGHT THROUGH A COUPLE OF HOURS AFTER SUNRISE EACH MORNING. MODEL GUIDANCE IS CONCUR ON A SURFACE LOW DEVELOPING ALONG THE MONSOON TROUGH NEAR 10N90W ON TUE WITH THE LOW MOVING W-NW THEREAFTER. USING A BLEND OF GUIDANCE TO POPULATE THE MARINE GRIDS AS THE GFS SOLUTION IS THE STRONGEST WITH WINDS THAN OTHERS MODELS. $$ NELSON