000 AXPZ20 KNHC 200304 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC TUE APR 20 2010 TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM THE EQUATOR TO 32N...EAST OF 140W. BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0245 UTC. ...ITCZ... AXIS ALONG 07N77W TO 05N100W TO 08N112W TO 05N140W. SCATTERED MODERATE CONVECTION WITHIN 60 NM S OF AXIS FROM 90W TO 95W. SCATTERED MODERATE ISOLATED STRONG CONVECTION WITHIN 90 NM OF AXIS W OF 137W. ...DISCUSSION... UPPER LEVEL TROUGH ENTERS BASIN FROM 32N134W TO 24N140W WITH VERY DRY AIR MASS N OF 21N W OF 122W DUE TO MODERATE TO STRONG SUBSIDENCE. DOWNSTREAM BROAD RIDGE ALONG 112W WITH ANTICYCLONIC CENTER AT 07N110W KEEP MONOPOLY ON CENTRAL PORTION OF E PAC TRAPPING SWATH OF ABUNDANT TROPICAL MOISTURE BROUGHT INTO BASIN ON STRENGTHENING 75 KT JET CORE JUST S-SE OF TROUGH BASE. QUICKLY WEAKENING UPPER LEVEL SHORT WAVE TROUGH OVER FOUR OVER SOUTHERN NEW MEXICO FLATTENS RIDGE CREST AND PROMPTS MODERATE TO STRONG DIFFLUENT PATTERN ALOFT ENHANCING HEALTHY CONVECTION OVER NORTHERN MEXICO AND BIG BEND AREA IN TEXAS N OF 28N. TROPICAL MOISTURE SOURCE HAS DECOUPLED FROM SHORT WAVE TROUGH SO CONVECTION EXPECTED TO DIMINISH WITHIN THE NEXT 24 HRS. FURTHER DOWNSTREAM...UPPER LEVEL LONGWAVE TROUGH EXTEND FROM FLORIDA PENINSULA ACROSS HONDURAS INTO E PAC THEN TO NOT-WELL-DEFINED CYCLONE AT 01N93W. TROUGH KEEPS AIR MASS FAIRLY DRY WITH DIMINISHING SCATTERED MODERATE CONVECTION S OF ITCZ E OF 95W. AT THE SURFACE... WEAK COLD FRONT EXTEND INTO E PAC FROM 32N128W TO 26N134W WITH HEALTHY 1028 MB HIGH PRES BEHIND IT. RIDGE REBUILDS OVER BASIN FROM THE NW THROUGH TUE BRINGING BACK FRESH TRADES W OF 125W INCREASING TO STRONG BY END OF FORECAST PERIOD. FRESH NW BREEZE PICKS UP ALONG BAJA CALIFORNIA COAST N OF 25N AS HIGH PRES DRIFT E. VERY LONG NW-SE FETCH ON RIDGE PERIPHERY BUILD LARGE LONG PERIOD NW SWELL ENTERING CORNER OF BASIN TONIGHT AND SPREAD AS FAR S AS 06N W OF 120W BY END OF FORECAST PERIOD. $$ WALLY BARNES