000 AXPZ20 KNHC 180959 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 1005 UTC SAT APR 18 2009 TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0830 UTC. ...ITCZ... ITCZ AXIS IS CENTERED ALONG A LINE FROM 05N77W TO 10N95W TO 08N113W TO 01N140W. THERE ARE NO AREAS OF SIGNIFICANT CONVECTION ASSOCIATED WITH THE ITCZ AT THIS TIME. ...DISCUSSION... W OF 105W...SCATTEROMETER SHOWS A BROAD SWATH OF 20 TO 25 KT TRADE WINDS GENERALLY N OF 06N AND W OF 115W...IN ADDITION TO PERSISTENT NW FLOW TO 20 KT OVER THE GULF OF CALIFORNIA...ON THE PERIPHERY OF A 1030 MB SURFACE HIGH PRES AREA CENTERED NEAR 35N130W. MEANWHILE THE ASSOCIATED UPPER RIDGE N OF 30N ALONG 130W IS BECOMING MORE AMPLIFIED AS IT SHIFTS EAST TOWARD THE U.S. WEST COAST...AHEAD OF A DEEPENING TROUGH OVER THE N CENTRAL PACIFIC. THIS WILL RESULT IN THE SURFACE HIGH PRES WEAKENING AND BEING DRAWN NORTHWARD THROUGH TODAY...ALLOWING THE TRADE WINDS AND GULF OF CALIFORNIA FLOW TO DIMINISH THROUGH SUNDAY. ANOTHER UPPER TROUGH IS NOTED S OF 20N ALONG 120W. ALTHOUGH DIVERGENT FLOW ALOFT ASSOCIATED WITH THIS FEATURE IS IS PLACE OVER THE ITCZ...ONLY VERY WEAK CONVECTION IS NOTED CURRENTLY. RESIDUAL NW AND NE SWELL WILL DECAY ACROSS THE AREA W OF 120W THROUGH SUNDAY...ALTHOUGH LONG PERIOD SW SWELL WILL MOVE ACROSS THE EQUATOR W OF 130W BY LATE SUNDAY. E OF 105W...ENHANCED TRADES FROM THE CARIBBEAN TOGETHER WITH DRAINAGE FLOW EFFECTS THIS MORNING ARE AIDING 20 KT EAST FLOW THROUGH THE GULF OF PAPAGAYO. SIMILARLY 20 KT NORTHERLY FLOW IS NOTED THROUGH THE ISTHMUS OF PANAMA. THESE WINDS WILL PERSIST THROUGH THE NEXT COUPLE OF DAYS...REACHING A MAXIMUM IN THE EARLY MORNING OVER THE GULF OF PAPAGAYO. OTHERWISE GLOBAL MODELS HINT OF A WEAK SURFACE TROUGH ALONG THE ITCZ MOVING FROM ROUGHLY 95W TO 105W THROUGH SUNDAY. WHILE SOME MID LEVEL CLOUDINESS IS NOTED BETWEEN 95W AND 100W...SCATTEROMETER DATA DO NOT SUPPORT PLACEMENT OF A TROUGH AS YET IN THIS AREA. NO MAJOR IMPACTS AT ANY RATE WITH THIS FEATURE OTHER THAN POSSIBLY SOME WEAK CONVECTION. LOOKING AHEAD...STRONG FLOW IS LIKELY THROUGH THE GULF OF TEHUANTEPEC STARTING MONDAY DUE TO LATE SEASON COLD FRONT MOVING INTO THE GULF OF MEXICO. LONG PERIOD SW SWELL WILL PUSH INTO THE MEXICAN AND CENTRAL AMERICAN COASTS BY TUE. $$ CHRISTENSEN