000 AXPZ20 KNHC 281550 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 1605 UTC SAT SEP 28 2013 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1545 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH AXIS EXTENDS ACROSS THE SW CARIBBEAN ALONG 09- 10N FROM THE NW COAST OF COLOMBIA TO ACROSS NORTHERN COSTA RICA TO THE PACIFIC COAST OF COSTA RICA AT 10N86W...THEN CONTINUES W ALONG 10N INTO A 1011 MB LOW PRES AT 09N100W WHICH IS FORECAST TO DISSIPATE OVER THE NEXT 24 HOURS . THE MONSOON TROUGH RESUMES AT A SECOND SURFACE LOW PRES DRIFTING NW AT 18N107W...CONTINUES SW TO A THIRD STATIONARY SURFACE LOW PRES AT 11N115W...THEN WSW TO 10N127W WHERE SCATTEROMETER WINDS INDICATE A TRANSITION TO AN ITCZ WHICH EXTENDS SW TO BEYOND 08N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED WITHIN 240 NM OVER THE S QUADRANT OF THE EMBEDDED SURFACE LOW AT 09N100W. SCATTERED MODERATE ISOLATED STRONG CONVECTION...WITH FREQUENT LIGHTNING... IS OBSERVED S OF THE EASTERN SEGMENT OF THE MONSOON TROUGH... ROUGHLY WITHIN 150 NM EITHER SIDE OF A LINE FROM 05.5N77W TO 13N95W...AND OVER AND TO THE N OF THE MONSOON TROUGH AXIS FROM 07-14N BETWEEN 91W-96W. ISOLATED MODERATE AND STRONG CONVECTION IS NOTED WITHIN 270 NM OVER THE E SEMICIRCLE OF THE SURFACE LOW AT 18N107W...AND WITHIN 60 NM OVER THE NE AND 420 NM OVER THE SW QUADRANTS OF THE SURFACE LOW AT 11N115W WHICH IS FORECAST TO CHANGE LITTLE OVER THE NEXT 24 HOURS. ...DISCUSSION... AN UPPER TROUGH EXTENDS SW ACROSS THE WESTERN CONUS AND INTO THE DISCUSSION AREA FROM NEAR 32N120W TO A UPPER CYCLONE CUTTING OFF AT 24N134W...WITH THE UPPER TROUGH CONTINUING S TO A BASE OVER THE TROPICAL PACIFIC AT 16N134W. ANOTHER UPPER CYCLONE IS NOTED FURTHER S OVER THE DEEP TROPICS AT 02N135W. EXPECT A N-S ORIENTATED TROUGH ALONG 133W TO EXTEND FROM THE CUTOFF CYCLONE TO THE TROPICAL CYCLONE IN JUST A FEW HOURS. IN THE MEANTIME... THESE UPPER FEATURES COMBINE TO DRY OUT THE UPPER LEVELS OF THE DISCUSSION AREA TO THE W OF A LINE EXTENDING FROM 30N130W TO 12N140W. AN UPPER ANTICYCLONE IS CENTERED OVER EXTREME SW LOUISIANA WITH AN UPPER RIDGE EXTENDING SW ACROSS NORTHERN OLD MEXICO AND THE SOUTHERN GULF OF CALIFORNIA TO A CREST OVER THE PACIFIC AT 14N131W. A SECOND UPPER ANTICYCLONE IS EMBEDDED WITHIN THE LARGER RIDGE NEAR 23N107W...WITH AN UPPER RIDGE EXTENDING SE TO 15N98W. UPPER DIFFLUENCE ALONG THE SOUTHERN PERIPHERY OF THIS MERGED UPPER RIDGE IS IN PHASE WITH THE LOWER LEVEL MONSOON TROUGH AND IS ENHANCING THE AREAS OF CONVECTION PREVIOUSLY DESCRIBED. THE RESULTANT DEBRIS MOISTURE REMAINS UNDER THE UPPER ANTICYCLONIC ENVELOPE. A LONGWAVE UPPER TROUGH IS OVER THE WESTERN N-ATLANTIC AND CONTINUES SW ACROSS THE NW CARIBBEAN AND ACROSS CENTRAL AMERICA AT 15N89W TO BASE OVER THE DEEP TROPICAL PACIFIC AT 10N99W WHERE A 1011 MB SURFACE LOW PREVIOUSLY MENTIONED S ANALYZED. TO THE E OF THIS UPPER TROUGH IS AN UPPER RIDGE EXTENDING NW FROM AN UPPER ANTICYCLONE CENTERED OVER S AMERICA. THIS PATTERN RESULTS IN THE UPPER LEVELS BEING SLIGHTLY DIFFLUENT OVER THE TROPICAL PACIFIC TO THE E OF 95W... AND ENHANCING THE CONVECTION PREVIOUSLY DESCRIBED ALONG THE COAST OF CENTRAL AMERICA. THE RESULTANT DENSE UPPER DEBRIS MOISTURE IS ADVECTED S TO ALONG 05N BETWEEN 77W-89W. ELSEWHERE AT THE SURFACE...A SURFACE HIGH IS ANALYZED NW OF THE DISCUSSION AREA NEAR 35N142W WITH A RIDGE EXTENDING SE TO A CREST AT 19N112W ACCOMPANIED BY ANTICYCLONIC WINDS AT 10-15 KT AND SEAS OF 4-7 FT. ALTHOUGH THE GRADIENT IS NOT EXPECTED TO TIGHTEN...LONG PERIOD NW SWELLS ARE FORECAST TO PROPAGATE S INTO THE NW PORTION OF THE DISCUSSION AREA ON SUN NIGHT...DRIVING COMBINED SEA HEIGHTS UP TO 12 FT. THESE NW SWELLS...IN THE FORM OF COMBINED SEAS OF 8-10 FT...WILL ARRIVE ALONG THE PACIFIC COAST OF THE BAJA CALIFORNIA PENINSULA ON MON...CONTINUING TO TO PROPAGATE SE COVING MOST OF THE PACIFIC WATERS N OF 10N W OF 113W BY THE MIDDLE OF NEXT WEEK. THE SWELLS ARE WILL THEN GRADUALLY SUBSIDE THROUGH THE REMAINDER OF THE WEEK. GULF OF CALIFORNIA...NORTHERLY WINDS AT 15-20 KT...SEAS 3-5 FT... ARE CURRENTLY OBSERVED ACROSS THE GULF WATERS N OF 28N. THESE WINDS WILL DIMINISH TO 10 KT ON SUN. $$ NELSON