000 AXPZ20 KNHC 110332 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC SUN NOV 11 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 0330 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS W FROM THE COAST OF COLOMBIA AT 07N78W TO AN EMBEDDED TROUGH AT 10N120W. LOW LEVEL WINDS INDICATE A TRANSITION TO AN ITCZ SW OF THE TROUGH NEAR 10N122W AND WITH THE ITCZ CONTINUING W TO BEYOND 08N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED WITHIN 30 NM OF 04N81.5W...WITHIN 120 NM EITHER SIDE OF A LINE FROM 09N100W TO 09.5N109W...WITHIN 90 NM OF 11N114W...WITHIN 120 NM EITHER SIDE OF A LINE FROM 14N121W TO 13N132W...AND WITHIN 60 NM OF 08N126W. SCATTERED MODERATE CONVECTION IS NOTED WITHIN 30 NM 11N135W. ...DISCUSSION... A LONGWAVE UPPER TROUGH HAS MOVED E TO OVER WESTERN N AMERICA WITH ITS MEAN AXIS CONTINUING S INTO THE DISCUSSION AREA FROM 32N111W TO A BASE OVER THE GULF OF CALIFORNIA AT 27N112W. A REINFORCING SHORTWAVE TROUGH IS ROTATING THROUGH THE LONGWAVE PATTERN WITH ITS AXIS FROM 32N115W TO 23N123W. AN UPPER CYCLONE HAS NEARLY CUT OFF 23N141W WITH SCATTERED MODERATE CONVECTION OBSERVED OVER THE DISCUSSION AREA WITHIN 45 NM EITHER SIDE OF A LINE FROM 26N140W TO 26N134W. THE DEBRIS MOISTURE IS SPREADING NE WITHIN 120 NM OF LINE 26N140W TO 25N131W. THIS PATTERN IS PRODUCING A SOUTHWESTERLY UPPER JET ACROSS THE DISCUSSION AREA WITHIN ABOUT 270 NM EITHER SIDE OF A LINE FROM 15N140W TO 21N120W TO BEYOND 30N100W WHICH IS ADVECTING UPPER DEBRIS MOISTURE...MOSTLY ORIGINATING FROM ITCZ CONVECTION BETWEEN 145W-160W...NE ACROSS NORTHERN OLD MEXICO AND EVENTUALLY FANNING OUT OVER THE S-CENTRAL CONUS. AN UPPER RIDGE EXTENDS E ACROSS THE DEEP TROPICS FROM ABOUT 05N140W TO 05N123W AND PROVIDES UPPER DIFFLUENCE WHICH IS SUPPORTING THE MONSOON TROUGH AND ITCZ CONVECTION PREVIOUSLY DESCRIBED TO THE W OF 121W. SOME OF THE DEBRIS MOISTURE SPREADS NE AND MERGES WITH THE SOUTHWESTERLY PLUME ALREADY DESCRIBED...WHILE SOME OF THE DEBRIS MOISTURE IS ALSO ADVECTED S ACROSS THE EQUATOR BETWEEN 126W-135W. AN UPPER LEVEL ANTICYCLONE IS CENTERED AT 09N96W WITH AN UPPER RIDGE EXTENDING NE ACROSS THE CENTRAL GULF OF MEXICO INTO THE LONGWAVE RIDGE SHIFTING E ACROSS EASTERN N AMERICA. AN UPPER RIDGE ALSO EXTENDS W FROM THE ANTICYCLONE TO A CREST OVER THE DEEP TROPICS AT 14N116W. UPPER DIFFLUENCE ALONG THIS TROPICAL RIDGE IS ENHANCING THE MONSOON TROUGH CONVECTION ALREADY DESCRIBED BETWEEN 100W-109W...WITH THE DEBRIS MOISTURE ORGANIZING INTO A THIN TROPICAL PLUME NOTED WITHIN 180 NM OF LINE FROM 12N113W TO BEYOND 25N100W WHERE IT MERGES WITH THE OTHER TROPICAL PLUME PREVIOUSLY MENTIONED. UPPER DIFFLUENCE IS ALSO ENHANCED MONSOON TROUGH CONVECTION ALONG 05N BETWEEN 79W-86W...WITH THE DEBRIS MOISTURE NOW ADVECTED S ACROSS THE EQUATOR BETWEEN 78W-87W. OTHERWISE DRY UPPER AIR IS NOTED OVER THE DISCUSSION AREA E OF 99W...AND S OF 07N BETWEEN 99W-117W... WITH AN BROAD INVERTED UPPER TROUGH OBSERVED TO THE S OF 08N BETWEEN 106W-116W. THE LONGWAVE UPPER TROUGH WILL PROGRESS E ACROSS CENTRAL N AMERICA THROUGH SUN. THE UPPER CYCLONE AT 23N141W WILL BE PICKED BY ANOTHER SHORTWAVE APPROACHING THE NW CORNER OF THE AREA...AND RACE NE ACROSS THE NW PORTION OF THE AREA FILLING NEAR 31N128W ON SUN NIGHT. THEREAFTER...A STRONG WESTERLY UPPER FLOW...AT 50-110 KT...WILL DOMINATE THE ENTIRE AREA N OF 15N WELL INTO NEXT WEEK. THE UPPER TROUGH WILL DRAG A WEAK COLD FRONT ACROSS THE CENTRAL GULF OF CALIFORNIA LATE TONIGHT INTO SUN ACCOMPANIED BY SW-W-NW 10-15 KT WIND SHIFT. STRONG SURFACE HIGH PRESSURE IS BUILDING S ACROSS THE N-CENTRAL WATERS ACCOMPANIED BY 15-20 KT...BUT IS EXPECTED TO INCREASE TO 20-25 KT IN THE AREA FROM 12N-18N BETWEEN 118W-140W ON MON AND TUE. NORTHWESTERLY WINDS AT 15-20 KT...SEAS 6-8 FT...ARE OBSERVED ALONG WESTERN BAJA CALIFORNIA TO THE N OF 29N...WITH THESE CONDITIONS EXPECTED TO QUICKLY SPREAD S ALONG THE ENTIRE W COAST OF BAJA LATE TONIGHT. EXPECT NW WINDS BEHIND THE FRONT TO INCREASE TO 20-25 KT ACROSS THE ENTIRE GULF OF CALIFORNIA FROM SUN EVENING THROUGH MON NIGHT...THEN BEGIN TO DIMINISH. THE INVERTED UPPER TROUGH OVER THE DEEP TROPICS WILL CONTINUE WITH AN UPPER CYCLONE DEVELOPING ALONG THE TROUGH AT 02N. THIS UPPER TROUGH/CYCLONE WILL CONTINUE TO SEPARATE THE UPPER FLOW OVER THE SOUTHERN PORTION OF THE DISCUSSION AREA THROUGH EARLY NEXT WEEK. SOUTHERLY CROSS EQUATORIAL FLOW WILL RESULT IN COMBINED SEAS OF 4-7 FT ACROSS THE TROPICS S OF 10N THROUGH ALL OF NEXT WEEK. NORTHERLY WINDS AT 20-25 KT...SEAS 6-9 FT...IN AND JUST DOWNSTREAM OF THE GULF OF TEHUANTEPEC WILL CONTINUE TO DIMINISH/SUBSIDE TONIGHT AND SUN. THE NORTHERLY SWELLS PRODUCED FROM THE RECENT TEHUANTEPEC EVENT ARE MIXING WITH CROSS EQUATORIAL SW SWELL ACROSS THE TROPICS FROM ABOUT 05N-10N BETWEEN 100W-105W. EXPECTING AN INVERTED LOW LEVEL TROUGH... POSSIBLY WITH A WEAK SURFACE LOW...TO DEVELOP FROM 06N-10N BETWEEN 105W-108W ON SUN...AND MOVE W THROUGH MON....ACCOMPANIED BY A NE-E-SE WIND AT 15-20 KT...SEAS TO 8 FT. NLY WINDS WILL AGAIN SURGE AT 15-20 KT INTO THE GULF OF TEHUANTEPEC LATE MON...AND RAPIDLY INCREASE TO MINIMAL GALE FORCE MON EVENING. THIS NEXT TEHUANTEPEC EVENT IS EXPECTED TO LAST THROUGH THU MORNING. IN THE MEANTIME EXPECT THE NE 20-25 KT WINDS...SEAS 7-9 FT...TO CONTINUE TO SURGE THROUGH A GAP IN THE CORDILLERA INTO AND JUST DOWNSTREAM OF THE GULF OF PAPAGAYO THROUGH SUN AFTERNOON THEN DIMINISH TO 15-20 KT MON NIGHT AND MON...THEN INCREASE AGAIN LATE MON NIGHT. $$ NELSON