000 AXPZ20 KNHC 102140 CCA TWDEP TROPICAL WEATHER DISCUSSION...CORRECTED NWS NATIONAL HURRICANE CENTER MIAMI FL 2205 UTC SAT SEP 10 2011 ...CORRECTED TO ADD A SPECIAL FEATURE... 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 2115 UTC. ...SPECIAL FEATURE... A SURFACE LOW PRESSURE EMBEDDED IN THE MONSOON TROUGH NEAR 16N117W IS ANALYZED AT 1008 MB. CONVECTION HAS BEEN FLARING WITHIN 60 NM OF THE CENTER. THIS LOW PRESSURE HAS THE POSSIBILITY OF BECOMING A TROPICAL CYCLONE OVER THE NEXT FEW DAYS. ...ITCZ/MONSOON TROUGH... THE SOUTHERN SEGMENT OF THE MONSOON TROUGH EXTENDS W ACROSS COSTA RICA FROM 10N80W TO 10N93W...THEN TURNS NW OVER THE PACIFIC TO NEAR 20N108W...THEN TURNS SW THROUGH AN EMBEDDED 1011 MB LOW AT 19N111W...CONTINUE SW TO A 1008 MB SURFACE LOW AT 16N117W WHICH IS SHOWING SIGNS OF STRENGTHENING WHILE DRIFTING NE...THEN THE TROUGH CONTINUES SW TO A 1010 MB SURFACE LOW AT 13N132W. THE TROUGH EXTENDS FURTHER SW TO 10N141W WHERE LOW LEVEL WINDS INDICATE THAT THE ITCZ BEGINS. BROKEN TO LOCALLY OVERCAST MULTILAYERED CLOUDS WITH SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED NE OF A LINE FROM THE COLOMBIAN COAST AT 03N TO 07N91W...AND WITHIN 60 NM EITHER SIDE OF A LINE FROM 12N98W TO 18N108W. SIMILAR ACTIVITY IS OBSERVED WITHIN 60 NM OF 20N111W...16N118W...08N126W AND 13N134W. ...DISCUSSION... AN UPPER ANTICYCLONE IS CENTERED AT 29N140W WITH A RIDGE EXTENDING NE WELL BEYOND 32N139W EVENTUALLY CRESTING OVER NW CANADA. ANOTHER UPPER ANTICYCLONE IS IS OVER CENTRAL OLD MEXICO AT 21N101W WITH AN UPPER RIDGE EXTENDING W OVER THE PACIFIC TO A CREST AT 17N124W. TWO SHORTWAVE TROUGHS ARE EMBEDDED IN LONGWAVE RIDGE THAT DOMINATES N AMERICA. THE WESTERNMOST TROUGH STEMS FROM A DEEP LAYERED CYCLONE OVER SOUTHERN CALIFORNIA WITH THE UPPER TROUGH AMPLIFYING SW TOWARDS TO AN UPPER CYCLONE AT 18N131W WHICH IN TURN HAS AN UPPER TROPOSPHERIC TROUGH EXTENDING SW TO ANOTHER SMALL UPPER CYCLONE AT 12N141W. THIS DEEPENING UPPER TROUGH EFFECTIVELY SEPARATES THE UPPER SUBTROPICAL RIDGE INTO THE TWO SEGMENTS PREVIOUSLY DESCRIBED. AN ASSOCIATED 1005 MB SURFACE LOW IS OVER SOUTHERN CALIFORNIA WITH A HEAT TROUGH EXTENDING S ACROSS THE BAJA CALIFORNIA PENINSULA. THIS UPPER TROUGH IS FORECAST TO CONTINUE EASTWARD TO ALONG 123W ON SUN. CONVECTION IS ENHANCED OVER CALIFORNIA NE OF THE SURFACE LOW...WITH THE DEBRIS MOISTURE ADVECTED E IN THE UPPER ZONAL FLOW ACROSS ARIZONA...NEW MEXICO AND NORTHERN TEXAS...THEN TURNING SE INTO THE EASTERN SHORTWAVE TROUGH THAT EXTENDS S OVER THE NW GULF OF MEXICO. THE UPPER LEVELS APPEAR DRY ELSEWHERE W OF OF A LINE FROM 15N130W TO 30N108W. THE UPPER RIDGE EXTENDING W FROM MEXICO IS ROUGHLY IN PHASE WITH THE LOWER LEVEL MONSOON TROUGH AND ENHANCES THE CONVECTION AS PREVIOUSLY MENTIONED. THE DEBRIS MOISTURE FANS OUT OVER THE TROPICAL PACIFIC S OF 17N E OF 127W AND MERGES WITH THE DEBRIS MOISTURE FROM TROPICAL CYCLONE NATE IN THE BAY OF CAMPECHE... AND DEBRIS MOISTURE FROM PREVIOUSLY MENTIONED CONVECTION ASSOCIATED WITH THE MONSOON TROUGH OVER THE PACIFIC S OF CENTRAL AMERICA. GULF OF CALIFORNIA...SOUTHERLY WINDS AT 15 TO 20 KT WILL CONTINUE OVER THE WATERS N OF 29N THROUGH EARLY TONIGHT...THEN DIMINISH EARLY SUN. NORTHERLY SWELLS...RESULTING IN COMBINED SEAS OF 8 FT...WILL MOVE INTO THE WATERS N OF 29N BETWEEN 119W AND 128W TODAY... SPREADING S TO ALONG 25N BETWEEN 120W AND 136W BY EARLY NEXT WEEK. CROSS EQUATORIAL SOUTHERLY SWELL...WITH SEAS TO 9 FT... WILL MOVE N OVER THE WATERS S OF 10N BETWEEN 130W AND 93W OVER THE WEEKEND. $$ NELSON