000 AXPZ20 KNHC 260247 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC MON APR 26 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 0100 UTC. ...ITCZ... THE INTERTROPICAL CONVERGENCE ZONE AXIS WAS ANALYZED ALONG 08N78W TO 06N90W TO 05N105W TO 07N124W TO 04N140W. SCATTERED MODERATE WITH ISOLATED STRONG CONVECTION WAS WITHIN 180 NM EITHER SIDE OF THE ITCZ AXIS E OF 96W AND ELSEWHERE WITHIN 60 NM OF COAST FROM 09N TO 12N. JUST N OF THIS AREA WAS SCATTERED MODERATE WITH ISOLATED STRONG FROM 10N TO 12N BETWEEN 91W AND 94W. ...DISCUSSION... A RIDGE AXIS EXTENDS SW TO NEAR 15N110W FROM A 1024 MB HIGH CENTERED AT 30N134W. THIS WEAK HIGH PRES SYSTEM HAS BEEN COMPROMISED BY BOTH AN UPPER LEVEL TROUGH PASSING THROUGH N WATERS OVER IT AND A STRONG COLD FRONT IMPINGING UPON IT FROM THE NW. THE DISSIPATING HIGH CENTER WILL MERGE WITH STRONGER HIGH PRES TO THE W ON MON. THE LATEST ASCAT PASSES AT 1742 AND 1922 UTC SHOW THE AREA OF FRESH TRADE WINDS FROM 10N TO 15N W OF 120W AND SHIP NWS0009 NEAR 11N122W REPORTED 19 KT WINDS AT 2300 UTC WHILE SHIP WTEU REPORTED 20 KT WINDS NEAR 12N122W AT 0000 UTC ON THE FAR E EDGE OF THE TRADE AREA. THE TRADES WILL CONTRACT TO THE W MON AS THE HIGHEST PRES SHIFTS W. MEANWHILE...A 100-120 KT SOUTHWESTERLY UPPER JET ON THE LEADING EDGE OF THE TROUGH OVER N WATERS IS TRANSPORTING UPPER LEVEL MOISTURE MANIFESTED AS CIRRUS NORTHEASTWARD FROM THE ITCZ JUST W OF THE AREA INTO NE WATERS OFF CENTRAL BAJA CALIFORNIA. LOOK FOR THE CIRRUS SHIELD TO SHIFT E WITH THE UPPER TROUGH AND ITS ASSOCIATED JET. BY TUE MORNING...THE COLD FRONT IMPINGING UPON THE NW SIDE OF THE SURFACE HIGH WILL MAKE ITS WAY INTO NW WATERS AS A WEAK LOW LEVEL BOUNDARY. THE PRIMARY IMPACT FROM THE SYSTEM WILL BE A SURGE IN NW SWELL WITH SIGNIFICANT WAVE HEIGHTS RISING TO 10 FT IN NW WATERS TUE EVENING. A SURFACE TROUGH IS EMBEDDED IN THE ITCZ FROM 12N122W TO 02N129W. DESPITE THE FACT THAT THIS TROUGH LIES UNDER AN UPPER RIDGE AXIS...ONLY HIGHLY SCATTERED CONVECTION IS NOTED ALONG THE ITCZ NEAR THE TROUGH WHICH LIES IN A RELATIVE MINIMUM OF AVAILABLE LOW LEVEL MOISTURE. THE UPPER RIDGE AXIS EXTENDS NE INTO AN ANTICYCLONE NEAR 14N110W THAT IS EXPECTED TO SLOWLY MOVE EASTWARD AWAY FROM THE SURFACE TROUGH AS THE AFOREMENTIONED UPPER TROUGH TO ITS NW MOVES THROUGH N WATERS. THE DIFFLUENCE ASSOCIATED WITH THE REAR RIGHT QUADRANT OF THE JET ON THE LEADING EDGE OF THIS UPPER TROUGH MAY HELP INCREASE THE CHANCE OF CONVECTION NEAR THE SURFACE TROUGH AS SLOWLY MOVES W MON AND TUE. A BROAD LOW LEVEL CYCLONIC GYRE LIES OVER SE WATERS. THE 1422 UTC ASCAT PASS SHOWED 20 TO 25 KT SW WINDS FEEDING INTO THE EASTERN EDGE OF THE GYRE AND SHIP A8NQ5 REPORTED 24 KT S WINDS NEAR 03N84W AT 1500 UTC...BUT THERE HAVE BEEN NO NEW OBSERVATIONS SINCE. SATELLITE PRECIPITABLE WATER VALUES ARE AT OR ABOVE 2.5 INCHES IN MUCH OF THE AREA E OF 95W...ALLOWING FOR PLENTY OF LOW LEVEL MOSITURE TO CONVERGE ALONG THE ITCZ. STRONG CONVECTION WILL LIKELY REMAIN OVER THE AREA E OF 95W FOR THE NEXT FEW DAYS AS CONDITIONS ALOFT ARE EXPECTED TO REMAIN DIFFLUENT BETWEEN THE SE EDGE OF A WEAKENING AND EASTWARD MOVING UPPER LEVEL ANTICYCLONE THAT CURRENTLY RESIDES OVER THE WESTERN CARIBBEAN AND ANOTHER ANTICYCLONE S OF THE EQUATOR NEAR 13S85W THAT IS ALSO EXPECTED TO MOVE EASTWARD. FINALLY...LARGE LONG PERIOD NW SWELLS WILL CONTINUE TO PROPAGATE SE THROUGH THE BASIN AND MERGE WITH CROSS-EQUATORIAL SW SWELL ACROSS THE TROPICS THROUGH TUE. $$ SCHAUER