000 AXPZ20 KNHC 250343 TWDEP TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 0405 UTC SUN APR 25 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 0315 UTC. ...ITCZ... THE INTERTROPICAL CONVERGENCE ZONE WAS ANALYZED ALONG 07N78W TO 08N104W TO 07N115W TO 08N123W TO 05N140W. A TROUGH IS EMBEDDED IN THE ITCZ FROM 10N86W TO 02N87W...NUMEROUS MODERATE TO STRONG CONVECTION WAS WITHIN 330 NM E OF THE TROUGH N OF 07N WHILE SCATTERED MODERATE CONVECTION WAS WITHIN 330 NM E OF TROUGH FROM 03N TO 07N AND WITHIN 75 NM W OF TROUGH FROM 06N TO 09N. SCATTERED MODERATE CONVECTION WAS WITHIN 120 NM N AND 60 NM S OF THE ITCZ AXIS BETWEEN 97W AND 102W. FARTHER W...ANOTHER TROUGH IS EMBEDDED IN THE ITCZ FROM 09N134W TO 03N136W. SCATTERED MODERATE CONVECTION WAS WITHIN 270 NM W OF TROUGH N OF 05N AND ELSEWHERE WITHIN 150 NM EITHER SIDE OF TROUGH. ...DISCUSSION... THE PRES GRADIENT BETWEEN 1003 MB LOW PRES OVER CENTRAL MEXICO NEAR 21N100W ON THE TAIL END OF A COLD FRONT THAT REACHES N INTO THE MISSISSIPPI VALLEY AND A RIDGE AXIS THAT EXTENDS SW TO NEAR 10N107W FROM A 1032 MB HIGH CENTERED AT 38N130W IS PRODUCING 20 TO 25 KT WINDS ALONG THE MEXICAN COAST NEAR MANZANILLO. SHIP A8PQ7 REPORTED 24 KT NE TO N WINDS AT 0000 UTC NEAR 20N107W. WINDS HERE ARE EXPECTED TO DIMINISH BELOW 20 KT BY SUN NIGHT AS THE COLD FRONT PULLS AWAY. IN ADDITION...THE AFOREMENTIONED HIGH PRES SYSTEM WILL WEAKEN AS AN UPPER LEVEL TROUGH PASSES THROUGH N WATERS OVER IT AND A STRONG COLD FRONT IMPINGES UPON IT FROM THE W. THIS WILL SEND THE DISSIPATING HIGH CENTER S INTO FORECAST WATERS SUN NIGHT. WHAT REMAINS OF THE HIGH WILL MERGE WITH STRONGER HIGH PRES TO THE W ON MON. THE 1802 UTC ASCAT PASS SHOWS FRESH TO STRONG TRADES OVER W WATERS PRIMARILY BETWEEN 08N AND 18N. THE TRADES WILL SHRINK IN AREA SIGNIFICANTLY SUN AS THE HIGH PRES TO THE N WEAKENS AND WILL REMAIN W OF 135W MON. MEANWHILE...A 100 KT SOUTHWESTERLY UPPER JET ON THE LEADING EDGE OF THE TROUGH OVER N WATERS IS TRANSPORTING UPPER LEVEL MOISTURE MANIFESTED AS CIRRUS NORTHEASTWARD THROUGH NW WATERS. LOOK FOR THE CIRRUS SHIELD TO SHIFT E WITH THE UPPER TROUGH AND ITS ASSOCIATED JET. THE LOW PRES CENTER PREVIOUSLY NEAR 05N86W AT 1800 UTC HAS WEAKENED TO A TROUGH OVER THE PAST 6 HOURS. THIS TROUGH LIES WITHIN A LARGER SCALE LOW LEVEL CYCLONIC GYRE OVER SE WATERS. THE 1442 ASCAT PASS SHOWED 20 TO 25 KT S TO SW WINDS FEEDING INTO THE GYRE. THERE HAVE BEEN NO NEW SHIP OBSERVATIONS HERE AND THE 2250 UTC WINDSAT PASS SHOWS LIGHT WINDS E OF 81W. 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. WHILE THIS SURFACE TROUGH IS EXPECTED TO DISSIPATE BY MON...STRONG CONVECTION WILL LIKELY REMAIN OVER THE AREA E OF 85W. AN UPPER LEVEL ANTICYCLONE THAT CURRENTLY RESIDES OVER EASTERN HONDURAS WILL SLOWLY MOVE EASTWARD...MAKING WAY FOR UPPER LEVEL FLOW TO BECOME INCREASINGLY DIFFLUENT OVER SE WATERS BETWEEN IT AND ANOTHER ANTICYCLONE S OF THE EQUATOR. JUST OVER THE PAST FEW HOURS...STRONG CONVECTION DEVELOPED ALONG THE COAST OF COLOMBIA. THERE WERE TWO TROUGHS EMBEDDED IN THE ITCZ W OF 90W. THE EASTERN TROUGH WAS FROM 11NW123W TO 04N125W WHILE THE WESTERN TROUGH WAS FROM 09N134N TO 03N136W. THE WESTERN TROUGH LIES UNDER AN UPPER LEVEL RIDGE AXIS AND HAS SOME SCATTERED MODERATE CONVECTION ASSOCIATED WITH IT. IT ALSO LIES ON THE EASTERN EDGE OF A POOL OF LOW LEVEL MOSITURE THAT IS EXPECTED TO MOVE W ALONG THE ITCZ. THE UPPER RIDGE AXIS WILL PINCH OFF AN ANTICYCLONE AND CARRY IT NE TO NEAR 12N110W BY SUN AFTERNOON INTO A REGION OF LESS LOW LEVEL MOISTURE. THIS MAY ALLOW FOR A SLIGHTLY BETTER CHANCE OF CONVECTION NEAR THE EASTERN TROUGH AS THE DIFFLUENT REGION ALOFT PASSES OVER IT SUN...BUT OVERALL LOOK FOR CONVECTION OVER THE CENTRAL AND WESTERN ITCZ TO REMAIN MEAGER THROUGH MON COMPARED TO SE WATERS. $$ SCHAUER