000 AXPZ20 KNHC 120337 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC MON NOV 12 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 NW COAST OF COLOMBIA AT 09N76W ACROSS THE SW CARIBBEAN AND EASTERN COSTA RICA TO 09N84W...THEN SW TO 07N94W WHERE LOW LEVEL WINDS INDICATE A TRANSITION TO AN ITCZ WHICH CONTINUES W THROUGH EMBEDDED 1009 MB LOW PRESSURE CENTERS AT 09N109W AND 09N120W TO BEYOND 08N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS ORGANIZED IN SMALL 30 NM DIAMETER CLUSTERS AT 08N78.5W...06N81W... 09N106.5W...08N110W...AND 09N120W AND ALSO WITHIN 90 NM EITHER SIDE OF A LINE FROM 12N134W TO 15.5N129.5W. ...DISCUSSION... A LONGWAVE UPPER TROUGH DOMINATES THE SUBTROPICS BETWEEN 93W-150W WITH TWO EMBEDDED SHORTWAVE TROUGHS NOTED. THE EASTERN MOST TROUGH IS OVER N AMERICA ALONG 105W AND EXTENDS S INTO THE DISCUSSION AREA FROM 32N103W TO A BASE AT 21N105W. THE WESTERN MOST UPPER TROUGH EXTENDS FROM 35N135W THROUGH AN EMBEDDED UPPER CYCLONE AT 28N133W...WITH THE TROUGH THEN EXTENDING SW TO 23N140W. AN UPPER ANTICYCLONE IS OVER THE DEEP TROPICS AT 06N131W WITH A SHORTWAVE RIDGE EXTENDING N TO BEYOND 32N122W EVENTUALLY ACROSS THE NW COAST OF THE CONUS. THIS UPPER PATTERN CREATES A LARGE AREA OF UPPER DIFFLUENCE...AND A SOUTHWESTERLY WIND MAXIMA...WITHIN ROUGHLY 360 NM EITHER SIDE OF A LINE FROM 12N135W TO 25N122W. A LARGE AREA OF DENSE MOISTURE CONCENTRATES INTO A TROPICAL PLUME COVERING THE DISCUSSION AREA FROM 10N-27N BETWEEN 132W-120W. THIS MOISTURE WILL CONTINUE E ACROSS THE UPPER RIDGE TONIGHT INTO EARLY MON...THEN ACCELERATE E AND NE INTO THE EASTERNMOST UPPER TROUGH ACROSS CENTRAL OLD MEXICO WHERE A PREVIOUS MOISTURE PLUME IS CURRENTLY EVAPORATING. THIS TROPICAL MOISTURE MAY BECOME SIGNIFICANT IF IT FEEDS INTO THE SURFACE FRONT PRECEDING THE SHORTWAVE OVER THE SE CONUS LATE MON. AN UPPER LEVEL ANTICYCLONE IS CENTERED AT 08N98W WITH AN UPPER RIDGE EXTENDING NE ACROSS THE EASTERN GULF OF MEXICO INTO THE LONGWAVE RIDGE COLLAPSING SE ACROSS EASTERN N AMERICA. AN UPPER RIDGE ALSO EXTENDS W FROM THE ANTICYCLONE THROUGH ANOTHER ANTICYCLONE AT 14N113W. UPPER DIFFLUENCE ALONG THIS TROPICAL RIDGE IS ENHANCING THE MONSOON TROUGH CONVECTION ALREADY DESCRIBED NEAR 09N106W AND 08N110W. UPPER DIFFLUENCE ALONG THE FAR SE PERIPHERY OF THE THE TROPICAL RIDGE IS ENHANCING CONVECTION NEAR PANAMA WITH THE DEBRIS MOISTURE NOW ADVECTED S ACROSS THE EQUATOR BETWEEN 80W-85W. OTHERWISE DRY UPPER AIR IS NOTED OVER THE DISCUSSION AREA E OF 100W...AND S OF 07N BETWEEN 100W-130W. AN UPPER CYCLONE IS NOTED OVER THE DEEP TROPICS AT 01N120W WITH AN INVERTED UPPER TROUGH EXTENDING NE TO 08N116W. THIS UPPER TROUGH WILL CONTINUE TO SEPARATE THE UPPER FLOW OVER THE SOUTHERN PORTION OF THE DISCUSSION AREA THROUGH AT LEAST THE MIDDLE OF NEXT WEEK. THE SHORTWAVE UPPER TROUGHS WILL PROGRESS EASTWARD OVER THE NEXT COUPLE OF DAYS EFFECTIVELY SHIFTING THE PARENT LONGWAVE TROUGH TO OVER EASTERN N AMERICA. THIS WILL RESULT IN STRONG WESTERLY ZONAL UPPER FLOW...AT 50-120 KT...DOMINATING THE ENTIRE DISCUSSION AREA N OF 16N THROUGH EARLY TUE. BY THEN A DEEP LAYERED TROUGH WILL APPROACH THE FAR NW PORTION DRIVING A SURFACE FRONT INTO THE AREA MON NIGHT ACCOMPANIED BY 15-20 KT SW-W-NW WIND SHIFT AND SEAS 6-9 FT W OF THE FRONT. IN THE MEANTIME...SURFACE HIGH PRESSURE HAS BUILT S ACROSS THE SUBTROPICAL AND TROPICAL WATERS N OF 10N TO THE W OF 110W. THE NE TRADES S OF A SURFACE RIDGE FROM 32N127W TO 16N107W HAVE INCREASED TO 20-25 KT...SEAS 8-12 FT...ACROSS THE WATERS FROM 12-27N BETWEEN 115-140W. EXPECT THIS AREA OF ENHANCED TRADES TO SHIFT TO THE W OF 118W ON MON...THEN DIMINISH TO 15-20 KT ON TUE AS SEAS SUBSIDE TO 7-11 FT. BAJA CALIFORNIA AREA...NORTHERLY WINDS AT 15-20 KT...SEAS 6-8 FT...CURRENTLY OBSERVED ALONG WESTERN BAJA CALIFORNIA WILL BEGIN TO DIMINISH TONIGHT AS THE LOW LEVEL WINDS CLOCK FROM N-NE WITH SEAS SUBSIDING TO 2-4 FT ALONG THE ENTIRE W COAST OF BAJA ON MON...WITH LITTLE CHANGE THROUGH MID WEEK. NW WINDS AT 20-25 KT ARE CURRENTLY OBSERVED OVER MOST OF THE GULF OF CALIFORNIA WITH LITTLE CHANGE EXPECTED THROUGH MON AFTERNOON...THEN THE GRADIENT WILL RELAX MAINTAINING ABOUT 15 KT ON WED...AND 10-15 KT ON THU. BEST GUESS IS SEAS WILL MAX AT ABOUT 8 FT OVER THE SOUTHERN GULF IN AREAS OF LONG UNINTERRUPTED NW FETCH. GULF OF PAPAGAYO...NE WINDS AT 15-20 KT WINDS...WITH SEAS 6-8 FT...ARE EXPECTED TO CONTINUE TO SURGE THROUGH A GAP IN THE CORDILLERA INTO AND JUST DOWNSTREAM OF THE GULF OF PAPAGAYO THROUGH AT LEAST MID WEEK. THESE EFFECTS ARE NOTED AS FAR W AS 09N91W. GULF OF TEHUANTEPEC...NORTHERLY WINDS AT 15-20 KT WILL DEVELOP IN THE GULF OF TEHUANTEPEC ON MON AFTERNOON...THEN RAPIDLY INCREASE TO GALE FORCE MON NIGHT...WITH SEAS BUILDING TO 10-15 FT EARLY TUE. THIS NEXT TEHUANTEPEC EVENT IS EXPECTED TO LAST THROUGH LATE THU NIGHT. $$ NELSON