000 AXPZ20 KNHC 092200 TWDEP TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 2205 UTC SUN JUN 09 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2145 UTC. ...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS W ALONG 10.5N FROM THE NW COAST OF COLOMBIA ACROSS NORTHERN COSTA RICA...TURNING BRIEFLY SW TO OVER THE PACIFIC AT 09N88W...THEN TURNS WNW TO 11N98W...THEN TURNS ABRUPTLY NW TO 13N107W WHERE IT TURNS SW AND THEN WIGGLES TO 08N130W WHERE SCATTEROMETER WINDS INDICATE A TRANSITION TO AN ITCZ. THE ITCZ AXIS CONTINUES JUST S OF DUE W TO BEYOND 07N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED WITHIN 180 NM EITHER SIDE OF A LINE FROM 06N78W TO 09N99W...WITHIN 75 NM EITHER SIDE OF A LINE FROM 06N101W TO 11N113W TO 08N128W. ISOLATED MODERATE TO OCCASIONALLY STRONG CONVECTION IS OBSERVED ELSEWHERE TO THE N OF 10N BETWEEN 102W AND THE COAST OF CENTRAL AMERICA. ...DISCUSSION... AN UPPER CYCLONE IS CENTERED AT 32N122W TRAILING AN UPPER TROUGH SW TO 22N128W. AT THE LOWER LEVELS A SURFACE LOW IS CENTERED AT 32N124W WITH A TROUGH EXTENDING FROM 32N120W TO 24N124W. SURFACE HIGH PRES W OF THIS SURFACE TROUGH IS MAINTAINING NE WINDS AT 20 KT...SEAS TO 8 FT IN N SWELL...ACROSS THE FORECAST WATERS TO THE N OF 28N BETWEEN 126W-134W. A SECOND UPPER CYCLONE HAS BEEN SHIFTING NE OVER THE PAST 24 HOURS AND IS CURRENTLY NEAR 28N145W. THE EASTERNMOST UPPER CYCLONE AT 32N122W IS EXPECTED TO MOVE NE TONIGHT-MON CROSSING OVER CENTRAL CALIFORNIA. THE CYCLONE FURTHER W WILL ALSO MOVE NE REACHING NEAR 31N135W ON MON...AND THEN SLOWLY FILL BEFORE PASSING OVER CALIFORNIA ON WED. THE SURFACE LOW IS EXPECTED TO MOVE S TO NEAR 30.5N125W ON MON WITH A WEAK COLD FRONT...OR MORE LIKELY A NON-BAROCLINIC TROUGH...DEVELOPING TO ITS S AND MOVING INTO THE AREA FROM 32N122W TO 26N127W ON TUE. NE SURFACE WINDS AT 20 KT WILL CONTINUE TO SPREAD SOUTHWARD INTO THE AREA W OF THE TROUGH... ACCOMPANIED BY COMBINED SEAS TO 9 FT THROUGH TUE. THE SURFACE TROUGH WILL FILL ON WED...BUT THE NORTHERLY 20 KT WINDS WILL CONTINUE THROUGH THU NIGHT ACROSS THE WATERS NW OF A LINE FROM 32N117W TO 20N140W AS NE TRADES INCREASE TO 20 KT ACROSS THE TROPICS TO THE W OF 125W AND N OF THE MONSOON TROUGH AND ITCZ DURING THE MIDDLE OF THE WEEK. AN UPPER ANTICYCLONE IS QUASI-STATIONARY AT 21N117W...WITH AN UPPER RIDGE EXTENDING E TO A CREST AT 18N110W. AN UPPER RIDGE ALSO EXTENDS W TO BEYOND 19N140W. THIS RIDGE IS ACCOMPANIED BY DRY UPPER AIR ALOFT...AND CONTINUES TO SUPPRESS CONVECTIVE DEVELOPMENT ACROSS THE AREA TO THE N OF 13N W OF 104W. WEAK UPPER DIFFLUENCE ALONG THE SOUTHERN PERIPHERY OF THIS UPPER RIDGE IS ROUGHLY IN PHASE WITH THE LOWER LEVEL MONSOON TROUGH AXIS...AND IS SUPPORTING THE CONVECTION PREVIOUSLY DESCRIBED BETWEEN 110W-133W. A VIGOROUS UPPER TROUGH OVER THE CENTRAL CONUS IS AMPLIFYING S ACROSS CENTRAL OLD MEXICO WITH EVIDENCE OF AN UPPER CYCLONE DEVELOPING NEAR 23N110W ATTM. GUIDANCE SEEMS TO AGREE...AND HAS THIS CYCLONE CUTTING OFF OVER N-CENTRAL OLD MEXICO ON TUE...AND THEN BECOMING ELONGATED SW OVER THE PACIFIC TO NEAR 19N112W BY MID WEEK. IN THE MEANTIME THE UPPER TROUGH IS SEPARATING THE UPPER FLOW OVER THE TROPICS TO THE E AND W OF 105W...AND SETTING OFF SMALL CLUSTERS OF CONVECTION OVER INTERIOR MEXICO TO THE N OF 22N E OF 105W. AN UPPER ANTICYCLONE THAT WAS OVER THE YUCATAN PENINSULA YESTERDAY HAS SHIFTED NE TO OVER THE SE GULF OF MEXICO NEAR 24N84W WITH AN UPPER RIDGE EXTENDING SW ACROSS CENTRAL AMERICA BETWEEN 87W-95W TO A CREST OVER THE PACIFIC AT 12N94W. OF NOTE IS THAT THIS PATTERN NOW RESULTS IN NW-N AND SLIGHTLY DIFFLUENT FLOW ALOFT OVER SOUTHERN FLORIDA AND WESTERN CUBA...WITH FAIRLY STRONG SOUTHEASTERLY LOW LEVEL FLOW ACCOMPANIED BY BRIEF HEAVY SHOWERS. AN UPPER LEVEL CYCLONE IS CUTTING OFF FROM A TUTT OVER THE N- CENTRAL CARIBBEAN IN THE VICINITY OF THE WINDWARD PASSAGE...BUT CONTINUES TO HAVE AN UPPER TROUGH EXTENDING SSW ACROSS PANAMA INTO AN UPPER CYCLONE OVER THE DEEP TROPICAL PACIFIC AT 03N79W. THESE UPPER FEATURES COMBINE TO SET OF AN AREA OF UPPER DIFFLUENCE OVER THE TROPICAL PACIFIC E OF 105W AND SUPPORTING THE CONVECTION WITHIN THE EASTERN SEGMENT OF MONSOON TROUGH AS PREVIOUSLY DESCRIBED. $$ NELSON