000 AXPZ20 KNHC 012159 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 2205 UTC SAT MAY 01 2010 TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2145 UTC. ...ITCZ... AXIS ANALYZED FROM 10N86W TO 05N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED FROM 03N TO 10N BETWEEN 92W AND 102W CURRENTLY DECREASING IN INTENSITY AND COVERAGE...AND DISSIPATING WITHIN 60 NM OF 04N109W...AND FLARING INTERMITTENTLY WITHIN 90 NM EITHER SIDE OF A LINE FROM 04N125W TO 05N132W. ...DISCUSSION... A POSITIVE TILT LONGWAVE UPPER TROUGH DOMINATES THE WESTERN CONUS WITH ITS MEAN AXIS EXTENDING INTO THE DISCUSSION AREA FROM 32N108W TO A BASE NEAR 19N118W. UPPER MOISTURE CONTINUES TO SPREAD SE INTO THE TROUGH OVER THE DISCUSSION AREA BETWEEN 108W AND 140W...BUT ALMOST COMPLETELY EVAPORATES ALONG 30N. ALTHOUGH A LONGWAVE RIDGE IS NOW DOMINATING THE EASTERN PACIFIC IT REMAINS W OF 140W OVER AREA TO THE S OF 30N. AN UPPER ANTICYCLONE IS QUASI STATIONARY NEAR 13N88W WITH AN UPPER RIDGE EXTENDING WSW ACROSS THE TROPICAL PACIFIC THROUGH 05N120W TO A SHARP CREST AT 07N138W. ITCZ CONVECTION HAS BEEN ENHANCED UNDER THE ENTIRE UPPER RIDGE...ESPECIALLY BETWEEN 80W AND 110W. A LOW LEVEL TROUGH HAS BEEN APPEARING INTERMITTENTLY FOR THE PAST FEW DAYS OVER THE PACIFIC WATERS ALONG THE COAST OF CENTRAL AMERICA. CURRENTLY THE TROUGH IS ANALYZED FROM 13N93W TO 10N88W. SCATTERED MODERATE ISOLATED STRONG CONVECTION FLARED E OF TROUGH TO COAST OF CENTRAL AMERICA...BUT IS NOW DIMINISHING. SHIP WECB MELVILLE NEAR 10N88W REPORTED WSW 20 KT AT 1800 UTC...BUT THE WESTERLY WIND DIRECTION IS ATTRIBUTED TO AN OUTFLOW BOUNDARY AT OBSERVATION TIME. THE AREA IS UNDER UNDER LEVEL DIFFLUENCE...CLOSE TO LAND...AND WILL BE MONITORED BY TROPICAL CYCLONE FORMATION. IN THE MEANTIME...THE RESULTANT DEBRIS MOISTURE FROM THIS CONVECTION AND ITCZ CONVECTION E OF 110W... IS ADVECTED S OF THE EQUATOR E OF 110W...AND ALSO ADVECTED NE ACROSS CENTRAL AMERICA TO THE W OF 83W. SOME OF THE DEBRIS MOISTURE FROM ITCZ CONVECTION BETWEEN 110W AND 140W SPREADS NE BUT EVAPORATES BEFORE REACHING 17N. THE UPPER LEVELS ARE VERY DRY N OF 17N ACROSS THE ENTIRE AREA. OVER THE NEXT FEW DAYS THE LONGWAVE TROUGH WILL SHIFT E T OVER CENTRAL N AMERICA AND THE LONGWAVE RIDGE WILL SHIFT E WITH ITS S TO N AXIS ALONG 140W BY TUE. ELSEWHERE AT THE SURFACE... A RIDGE AXIS IS MEANDERING FROM 32N132W TO NEAR 12N110W. NE TRADES THE S OF THE RIDGE AXIS ARE AT 15 TO 20 KT...WITH SEAS 8 TO 11 FT IN MIXED NE AND NW SWELL. NORTHERLY WINDS TO THE NE OF THE RIDGE AXIS REACH THE WESTERN BAJA PENINSULA...BUT HAVE DIMINISHED TO MOSTLY 20 KT...BUT ARE STILL ACCOMPANIED BY SEAS HEIGHTS TO 15 FT IN NW SWELL. SOUTHERLY WINDS CONTINUE AROUND THE SOUTHERN TIP OF THE BAJA PENINSULA...BUT BELIEVE THEY NO LONGER REFRACT INTO THE SOUTHERN GULF OF CALIFORNIA...BUT LIKELY CONTINUE E TO BANDERAS BAY ANCHORAGE. THE SOUTHERN EXTENT OF THESE NW SWELLS IS CURRENTLY ABOUT THE LATITUDE OF THE ITCZ W OF 115W WITH THE NW SWELLS EXPECTED TO REACH ALONG 100W BY LATE SUN. A NEW SERIES OF SOUTHERLY SWELLS WILL REACH THE EQUATOR TONIGHT NEAR 120W. THE NW AND SW SWELLS WILL MIX THROUGHOUT THE TROPICAL WATERS EARLY NEXT WEEK. $$ NELSON